Merge pull request #5974 from libgit2/ethomson/dlopen_ssl

Dynamically load OpenSSL (optionally)

31 files changed, 1852 insertions, 546 deletions

diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index e235a3ce7..47ebf464d 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -59,6 +59,14 @@ jobs:
             CMAKE_OPTIONS: -DTHREADSAFE=OFF -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=valgrind -DUSE_GSSAPI=ON
             CMAKE_GENERATOR: Ninja
           os: ubuntu-latest
+        - # Xenial, Clang, OpenSSL (dynamically loaded)
+          container:
+            name: xenial
+          env:
+            CC: clang
+            CMAKE_OPTIONS: -DUSE_HTTPS=OpenSSL-Dynamic -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=valgrind -DUSE_GSSAPI=ON
+            CMAKE_GENERATOR: Ninja
+          os: ubuntu-latest
         - # Focal, Clang 10, mbedTLS, MemorySanitizer
           container:
             name: focal
@@ -115,6 +123,14 @@ jobs:
             PKG_CONFIG_PATH: /usr/local/lib/pkgconfig
             SKIP_NEGOTIATE_TESTS: true
           os: ubuntu-latest
+        - # CentOS 7, OpenSSL (dynamically loaded)
+          container:
+            name: centos7
+          env:
+            CMAKE_OPTIONS: -DUSE_HTTPS=OpenSSL-Dynamic -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=valgrind -DUSE_GSSAPI=ON
+            PKG_CONFIG_PATH: /usr/local/lib/pkgconfig
+            SKIP_NEGOTIATE_TESTS: true
+          os: ubuntu-latest
         - # CentOS 8
           container:
             name: centos8
@@ -124,6 +140,15 @@ jobs:
             SKIP_NEGOTIATE_TESTS: true
             SKIP_SSH_TESTS: true
           os: ubuntu-latest
+        - # CentOS 8, OpenSSL (dynamically loaded)
+          container:
+            name: centos8
+          env:
+            CMAKE_OPTIONS: -DUSE_HTTPS=OpenSSL-Dynamic -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=valgrind -DUSE_GSSAPI=ON
+            PKG_CONFIG_PATH: /usr/local/lib/pkgconfig
+            SKIP_NEGOTIATE_TESTS: true
+            SKIP_SSH_TESTS: true
+          os: ubuntu-latest
         - # macOS
           os: macos-10.15
           env:
@@ -180,6 +205,16 @@ jobs:
             BUILD_PATH: D:\Temp\mingw32\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Program Files (x86)\CMake\bin
             SKIP_SSH_TESTS: true
             SKIP_NEGOTIATE_TESTS: true
+        - # Bionic, GCC, OpenSSL (dynamically loaded)
+          container:
+            name: bionic
+            dockerfile: bionic
+          env:
+            CC: gcc
+            CMAKE_GENERATOR: Ninja
+            CMAKE_OPTIONS: -DUSE_HTTPS=OpenSSL-Dynamic -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=valgrind -DUSE_GSSAPI=ON
+            RUN_INVASIVE_TESTS: true
+          os: ubuntu-latest
         - # Bionic, x86, Clang, OpenSSL
           container:
             name: bionic-x86
diff --git a/COPYING b/COPYING
index c0f61fb91..6bb39b0c1 100644
--- a/COPYING
+++ b/COPYING
@@ -420,7 +420,7 @@ The GNU C Library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.
- 
+
 The GNU C Library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
@@ -1019,3 +1019,111 @@ following restrictions are are met:
 THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+
+----------------------------------------------------------------------
+
+Portions of the OpenSSL headers are included under the OpenSSL license:
+
+Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+All rights reserved.
+
+This package is an SSL implementation written
+by Eric Young (eay@cryptsoft.com).
+The implementation was written so as to conform with Netscapes SSL.
+
+This library is free for commercial and non-commercial use as long as
+the following conditions are aheared to.  The following conditions
+apply to all code found in this distribution, be it the RC4, RSA,
+lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+included with this distribution is covered by the same copyright terms
+except that the holder is Tim Hudson (tjh@cryptsoft.com).
+
+Copyright remains Eric Young's, and as such any Copyright notices in
+the code are not to be removed.
+If this package is used in a product, Eric Young should be given attribution
+as the author of the parts of the library used.
+This can be in the form of a textual message at program startup or
+in documentation (online or textual) provided with the package.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+1. Redistributions of source code must retain the copyright
+   notice, this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+3. All advertising materials mentioning features or use of this software
+   must display the following acknowledgement:
+   "This product includes cryptographic software written by
+    Eric Young (eay@cryptsoft.com)"
+   The word 'cryptographic' can be left out if the rouines from the library
+   being used are not cryptographic related :-).
+4. If you include any Windows specific code (or a derivative thereof) from
+   the apps directory (application code) you must include an acknowledgement:
+   "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+
+THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGE.
+
+The licence and distribution terms for any publically available version or
+derivative of this code cannot be changed.  i.e. this code cannot simply be
+copied and put under another distribution licence
+[including the GNU Public Licence.]
+
+====================================================================
+Copyright (c) 1998-2007 The OpenSSL Project.  All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in
+   the documentation and/or other materials provided with the
+   distribution.
+
+3. All advertising materials mentioning features or use of this
+   software must display the following acknowledgment:
+   "This product includes software developed by the OpenSSL Project
+   for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+
+4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+   endorse or promote products derived from this software without
+   prior written permission. For written permission, please contact
+   openssl-core@openssl.org.
+
+5. Products derived from this software may not be called "OpenSSL"
+   nor may "OpenSSL" appear in their names without prior written
+   permission of the OpenSSL Project.
+
+6. Redistributions of any form whatsoever must retain the following
+   acknowledgment:
+   "This product includes software developed by the OpenSSL Project
+   for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+
+THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+OF THE POSSIBILITY OF SUCH DAMAGE.
+
diff --git a/cmake/SelectHTTPSBackend.cmake b/cmake/SelectHTTPSBackend.cmake
index afbeac424..4998f0f2a 100644
--- a/cmake/SelectHTTPSBackend.cmake
+++ b/cmake/SelectHTTPSBackend.cmake
@@ -108,6 +108,10 @@ IF(USE_HTTPS)
 		LIST(APPEND LIBGIT2_PC_LIBS ${MBEDTLS_LIBRARIES})
 	ELSEIF (USE_HTTPS STREQUAL "WinHTTP")
 		# WinHTTP setup was handled in the WinHTTP-specific block above
+	ELSEIF (USE_HTTPS STREQUAL "OpenSSL-Dynamic")
+		SET(GIT_OPENSSL 1)
+		SET(GIT_OPENSSL_DYNAMIC 1)
+		LIST(APPEND LIBGIT2_LIBS dl)
 	ELSE()
 		MESSAGE(FATAL_ERROR "Asked for backend ${USE_HTTPS} but it wasn't found")
 	ENDIF()
diff --git a/deps/ntlmclient/CMakeLists.txt b/deps/ntlmclient/CMakeLists.txt
index d933f4919..3e0d2c817 100644
--- a/deps/ntlmclient/CMakeLists.txt
+++ b/deps/ntlmclient/CMakeLists.txt
@@ -1,25 +1,37 @@
-FILE(GLOB SRC_NTLMCLIENT "ntlm.c" "unicode_builtin.c" "util.c")
+FILE(GLOB SRC_NTLMCLIENT "ntlm.c" "ntlm.h" "util.c" "util.h")
 LIST(SORT SRC_NTLMCLIENT)
 
 ADD_DEFINITIONS(-DNTLM_STATIC=1)
 
 DISABLE_WARNINGS(implicit-fallthrough)
 
+IF(USE_ICONV)
+	ADD_DEFINITIONS(-DUNICODE_ICONV=1)
+	FILE(GLOB SRC_NTLMCLIENT_UNICODE "unicode_iconv.c" "unicode_iconv.h")
+ELSE()
+	ADD_DEFINITIONS(-DUNICODE_BUILTIN=1)
+	FILE(GLOB SRC_NTLMCLIENT_UNICODE "unicode_builtin.c" "unicode_builtin.h")
+ENDIF()
+
 IF(USE_HTTPS STREQUAL "SecureTransport")
 	ADD_DEFINITIONS(-DCRYPT_COMMONCRYPTO)
-	SET(SRC_NTLMCLIENT_CRYPTO "crypt_commoncrypto.c")
+	SET(SRC_NTLMCLIENT_CRYPTO "crypt_commoncrypto.c" "crypt_commoncrypto.h")
 	# CC_MD4 has been deprecated in macOS 10.15.
 	SET_SOURCE_FILES_PROPERTIES("crypt_commoncrypto.c" COMPILE_FLAGS "-Wno-deprecated")
 ELSEIF(USE_HTTPS STREQUAL "OpenSSL")
 	ADD_DEFINITIONS(-DCRYPT_OPENSSL)
 	INCLUDE_DIRECTORIES(${OPENSSL_INCLUDE_DIR})
-	SET(SRC_NTLMCLIENT_CRYPTO "crypt_openssl.c")
+	SET(SRC_NTLMCLIENT_CRYPTO "crypt_openssl.c" "crypt_openssl.h")
+ELSEIF(USE_HTTPS STREQUAL "OpenSSL-Dynamic")
+	ADD_DEFINITIONS(-DCRYPT_OPENSSL)
+	ADD_DEFINITIONS(-DCRYPT_OPENSSL_DYNAMIC)
+	SET(SRC_NTLMCLIENT_CRYPTO "crypt_openssl.c" "crypt_openssl.h")
 ELSEIF(USE_HTTPS STREQUAL "mbedTLS")
 	ADD_DEFINITIONS(-DCRYPT_MBEDTLS)
 	INCLUDE_DIRECTORIES(${MBEDTLS_INCLUDE_DIR})
-	SET(SRC_NTLMCLIENT_CRYPTO "crypt_mbedtls.c")
+	SET(SRC_NTLMCLIENT_CRYPTO "crypt_mbedtls.c" "crypt_mbedtls.h")
 ELSE()
 	MESSAGE(FATAL_ERROR "Unable to use libgit2's HTTPS backend (${USE_HTTPS}) for NTLM crypto")
 ENDIF()
 
-ADD_LIBRARY(ntlmclient OBJECT ${SRC_NTLMCLIENT} ${SRC_NTLMCLIENT_CRYPTO})
+ADD_LIBRARY(ntlmclient OBJECT ${SRC_NTLMCLIENT} ${SRC_NTLMCLIENT_UNICODE} ${SRC_NTLMCLIENT_CRYPTO})
diff --git a/deps/ntlmclient/crypt.h b/deps/ntlmclient/crypt.h
index 48be39946..4ad543ef7 100644
--- a/deps/ntlmclient/crypt.h
+++ b/deps/ntlmclient/crypt.h
@@ -9,6 +9,9 @@
 #ifndef PRIVATE_CRYPT_COMMON_H__
 #define PRIVATE_CRYPT_COMMON_H__
 
+#include "ntlmclient.h"
+#include "ntlm.h"
+
 #if defined(CRYPT_OPENSSL)
 # include "crypt_openssl.h"
 #elif defined(CRYPT_MBEDTLS)
@@ -25,40 +28,42 @@
 
 typedef unsigned char ntlm_des_block[CRYPT_DES_BLOCKSIZE];
 
+typedef struct ntlm_crypt_ctx ntlm_crypt_ctx;
+
+extern bool ntlm_crypt_init(ntlm_client *ntlm);
+
 extern bool ntlm_random_bytes(
-	ntlm_client *ntlm,
 	unsigned char *out,
+	ntlm_client *ntlm,
 	size_t len);
 
 extern bool ntlm_des_encrypt(
 	ntlm_des_block *out,
+	ntlm_client *ntlm,
 	ntlm_des_block *plaintext,
 	ntlm_des_block *key);
 
 extern bool ntlm_md4_digest(
 	unsigned char out[CRYPT_MD4_DIGESTSIZE],
+	ntlm_client *ntlm,
 	const unsigned char *in,
 	size_t in_len);
 
-extern ntlm_hmac_ctx *ntlm_hmac_ctx_init(void);
-
-extern bool ntlm_hmac_ctx_reset(ntlm_hmac_ctx *ctx);
-
 extern bool ntlm_hmac_md5_init(
-	ntlm_hmac_ctx *ctx,
+	ntlm_client *ntlm,
 	const unsigned char *key,
 	size_t key_len);
 
 extern bool ntlm_hmac_md5_update(
-	ntlm_hmac_ctx *ctx,
+	ntlm_client *ntlm,
 	const unsigned char *data,
 	size_t data_len);
 
 extern bool ntlm_hmac_md5_final(
 	unsigned char *out,
 	size_t *out_len,
-	ntlm_hmac_ctx *ctx);
+	ntlm_client *ntlm);
 
-extern void ntlm_hmac_ctx_free(ntlm_hmac_ctx *ctx);
+extern void ntlm_crypt_shutdown(ntlm_client *ntlm);
 
 #endif /* PRIVATE_CRYPT_COMMON_H__ */
diff --git a/deps/ntlmclient/crypt_commoncrypto.c b/deps/ntlmclient/crypt_commoncrypto.c
index 54a0f097b..4ff57edd2 100644
--- a/deps/ntlmclient/crypt_commoncrypto.c
+++ b/deps/ntlmclient/crypt_commoncrypto.c
@@ -18,9 +18,15 @@
 #include "ntlm.h"
 #include "crypt.h"
 
+bool ntlm_crypt_init(ntlm_client *ntlm)
+{
+	memset(&ntlm->crypt_ctx, 0, sizeof(ntlm_crypt_ctx));
+	return true;
+}
+
 bool ntlm_random_bytes(
-	ntlm_client *ntlm,
 	unsigned char *out,
+	ntlm_client *ntlm,
 	size_t len)
 {
 	int fd, ret;
@@ -49,11 +55,14 @@ bool ntlm_random_bytes(
 
 bool ntlm_des_encrypt(
 	ntlm_des_block *out,
+	ntlm_client *ntlm,
 	ntlm_des_block *plaintext,
 	ntlm_des_block *key)
 {
 	size_t written;
 
+	NTLM_UNUSED(ntlm);
+
 	CCCryptorStatus result = CCCrypt(kCCEncrypt,
 		kCCAlgorithmDES, kCCOptionECBMode,
 		key, sizeof(ntlm_des_block), NULL,
@@ -65,56 +74,47 @@ bool ntlm_des_encrypt(
 
 bool ntlm_md4_digest(
 	unsigned char out[CRYPT_MD4_DIGESTSIZE],
+	ntlm_client *ntlm,
 	const unsigned char *in,
 	size_t in_len)
 {
+	NTLM_UNUSED(ntlm);
 	return !!CC_MD4(in, in_len, out);
 }
 
-ntlm_hmac_ctx *ntlm_hmac_ctx_init(void)
-{
-	return calloc(1, sizeof(ntlm_hmac_ctx));
-}
-
-bool ntlm_hmac_ctx_reset(ntlm_hmac_ctx *ctx)
-{
-	memset(ctx, 0, sizeof(ntlm_hmac_ctx));
-	return true;
-}
-
 bool ntlm_hmac_md5_init(
-	ntlm_hmac_ctx *ctx,
+	ntlm_client *ntlm,
 	const unsigned char *key,
 	size_t key_len)
 {
-	CCHmacInit(&ctx->native, kCCHmacAlgMD5, key, key_len);
+	CCHmacInit(&ntlm->crypt_ctx.hmac, kCCHmacAlgMD5, key, key_len);
 	return true;
 }
 
 bool ntlm_hmac_md5_update(
-	ntlm_hmac_ctx *ctx,
+	ntlm_client *ntlm,
 	const unsigned char *data,
 	size_t data_len)
 {
-	CCHmacUpdate(&ctx->native, data, data_len);
+	CCHmacUpdate(&ntlm->crypt_ctx.hmac, data, data_len);
 	return true;
 }
 
 bool ntlm_hmac_md5_final(
 	unsigned char *out,
 	size_t *out_len,
-	ntlm_hmac_ctx *ctx)
+	ntlm_client *ntlm)
 {
 	if (*out_len < CRYPT_MD5_DIGESTSIZE)
 		return false;
 
-	CCHmacFinal(&ctx->native, out);
+	CCHmacFinal(&ntlm->crypt_ctx.hmac, out);
 
 	*out_len = CRYPT_MD5_DIGESTSIZE;
 	return true;
 }
 
-void ntlm_hmac_ctx_free(ntlm_hmac_ctx *ctx)
+void ntlm_crypt_shutdown(ntlm_client *ntlm)
 {
-	free(ctx);
+	NTLM_UNUSED(ntlm);
 }
diff --git a/deps/ntlmclient/crypt_commoncrypto.h b/deps/ntlmclient/crypt_commoncrypto.h
index e4075c9f6..e4df91d29 100644
--- a/deps/ntlmclient/crypt_commoncrypto.h
+++ b/deps/ntlmclient/crypt_commoncrypto.h
@@ -11,8 +11,8 @@
 
 #include <CommonCrypto/CommonCrypto.h>
 
-typedef struct {
-	CCHmacContext native;
-} ntlm_hmac_ctx;
+struct ntlm_crypt_ctx {
+	CCHmacContext hmac;
+};
 
 #endif /* PRIVATE_CRYPT_COMMONCRYPTO_H__ */
diff --git a/deps/ntlmclient/crypt_mbedtls.c b/deps/ntlmclient/crypt_mbedtls.c
index bbab02d7d..6283c3eec 100644
--- a/deps/ntlmclient/crypt_mbedtls.c
+++ b/deps/ntlmclient/crypt_mbedtls.c
@@ -17,9 +17,24 @@
 #include "ntlm.h"
 #include "crypt.h"
 
+bool ntlm_crypt_init(ntlm_client *ntlm)
+{
+	const mbedtls_md_info_t *info = mbedtls_md_info_from_type(MBEDTLS_MD_MD5);
+
+	mbedtls_md_init(&ntlm->crypt_ctx.hmac);
+
+	if (mbedtls_md_setup(&ntlm->crypt_ctx.hmac, info, 1) != 0) {
+		ntlm_client_set_errmsg(ntlm, "could not setup mbedtls digest");
+		return false;
+	}
+
+	return true;
+}
+
+
 bool ntlm_random_bytes(
-	ntlm_client *ntlm,
 	unsigned char *out,
+	ntlm_client *ntlm,
 	size_t len)
 {
 	mbedtls_ctr_drbg_context ctr_drbg;
@@ -51,6 +66,7 @@ bool ntlm_random_bytes(
 
 bool ntlm_des_encrypt(
 	ntlm_des_block *out,
+	ntlm_client *ntlm,
 	ntlm_des_block *plaintext,
 	ntlm_des_block *key)
 {
@@ -60,8 +76,10 @@ bool ntlm_des_encrypt(
 	mbedtls_des_init(&ctx);
 
 	if (mbedtls_des_setkey_enc(&ctx, *key) ||
-		mbedtls_des_crypt_ecb(&ctx, *plaintext, *out))
+	    mbedtls_des_crypt_ecb(&ctx, *plaintext, *out)) {
+		ntlm_client_set_errmsg(ntlm, "DES encryption failed");
 		goto done;
+	}
 
 	success = true;
 
@@ -72,11 +90,14 @@ done:
 
 bool ntlm_md4_digest(
 	unsigned char out[CRYPT_MD4_DIGESTSIZE],
+	ntlm_client *ntlm,
 	const unsigned char *in,
 	size_t in_len)
 {
 	mbedtls_md4_context ctx;
 
+	NTLM_UNUSED(ntlm);
+
 	mbedtls_md4_init(&ctx);
 	mbedtls_md4_starts(&ctx);
 	mbedtls_md4_update(&ctx, in, in_len);
@@ -86,60 +107,40 @@ bool ntlm_md4_digest(
 	return true;
 }
 
-ntlm_hmac_ctx *ntlm_hmac_ctx_init(void)
-{
-	ntlm_hmac_ctx *ctx;
-	const mbedtls_md_info_t *info = mbedtls_md_info_from_type(MBEDTLS_MD_MD5);
-
-	if ((ctx = calloc(1, sizeof(ntlm_hmac_ctx))) == NULL)
-		return NULL;
-
-	mbedtls_md_init(&ctx->mbed);
-
-	if (mbedtls_md_setup(&ctx->mbed, info, 1) != 0) {
-		free(ctx);
-		return false;
-	}
-
-	return ctx;
-}
-
-bool ntlm_hmac_ctx_reset(ntlm_hmac_ctx *ctx)
-{
-	return !mbedtls_md_hmac_reset(&ctx->mbed);
-}
-
 bool ntlm_hmac_md5_init(
-	ntlm_hmac_ctx *ctx,
+	ntlm_client *ntlm,
 	const unsigned char *key,
 	size_t key_len)
 {
-	return !mbedtls_md_hmac_starts(&ctx->mbed, key, key_len);
+	if (ntlm->crypt_ctx.hmac_initialized) {
+		if (mbedtls_md_hmac_reset(&ntlm->crypt_ctx.hmac))
+			return false;
+	}
+
+	ntlm->crypt_ctx.hmac_initialized = !mbedtls_md_hmac_starts(&ntlm->crypt_ctx.hmac, key, key_len);
+	return ntlm->crypt_ctx.hmac_initialized;
 }
 
 bool ntlm_hmac_md5_update(
-	ntlm_hmac_ctx *ctx,
+	ntlm_client *ntlm,
 	const unsigned char *in,
 	size_t in_len)
 {
-	return !mbedtls_md_hmac_update(&ctx->mbed, in, in_len);
+	return !mbedtls_md_hmac_update(&ntlm->crypt_ctx.hmac, in, in_len);
 }
 
 bool ntlm_hmac_md5_final(
 	unsigned char *out,
 	size_t *out_len,
-	ntlm_hmac_ctx *ctx)
+	ntlm_client *ntlm)
 {
 	if (*out_len < CRYPT_MD5_DIGESTSIZE)
 		return false;
 
-	return !mbedtls_md_hmac_finish(&ctx->mbed, out);
+	return !mbedtls_md_hmac_finish(&ntlm->crypt_ctx.hmac, out);
 }
 
-void ntlm_hmac_ctx_free(ntlm_hmac_ctx *ctx)
+void ntlm_crypt_shutdown(ntlm_client *ntlm)
 {
-	if (ctx) {
-		mbedtls_md_free(&ctx->mbed);
-		free(ctx);
-	}
+	mbedtls_md_free(&ntlm->crypt_ctx.hmac);
 }
diff --git a/deps/ntlmclient/crypt_mbedtls.h b/deps/ntlmclient/crypt_mbedtls.h
index eb49a4596..2fc85035d 100644
--- a/deps/ntlmclient/crypt_mbedtls.h
+++ b/deps/ntlmclient/crypt_mbedtls.h
@@ -11,8 +11,9 @@
 
 #include "mbedtls/md.h"
 
-typedef struct {
-	mbedtls_md_context_t mbed;
-} ntlm_hmac_ctx;
+struct ntlm_crypt_ctx {
+	mbedtls_md_context_t hmac;
+	unsigned int hmac_initialized : 1;
+};
 
 #endif /* PRIVATE_CRYPT_MBEDTLS_H__ */
diff --git a/deps/ntlmclient/crypt_openssl.c b/deps/ntlmclient/crypt_openssl.c
index c0d36d891..463eae4f8 100644
--- a/deps/ntlmclient/crypt_openssl.c
+++ b/deps/ntlmclient/crypt_openssl.c
@@ -9,26 +9,166 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include <openssl/rand.h>
-#include <openssl/des.h>
-#include <openssl/md4.h>
-#include <openssl/hmac.h>
-#include <openssl/err.h>
+#ifdef CRYPT_OPENSSL_DYNAMIC
+# include <dlfcn.h>
+#else
+# include <openssl/rand.h>
+# include <openssl/des.h>
+# include <openssl/md4.h>
+# include <openssl/hmac.h>
+# include <openssl/err.h>
+#endif
 
 #include "ntlm.h"
 #include "compat.h"
 #include "util.h"
 #include "crypt.h"
 
+#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(CRYPT_OPENSSL_DYNAMIC)
+
+static inline HMAC_CTX *HMAC_CTX_new(void)
+{
+	return calloc(1, sizeof(HMAC_CTX));
+}
+
+static inline int HMAC_CTX_reset(HMAC_CTX *ctx)
+{
+	ntlm_memzero(ctx, sizeof(HMAC_CTX));
+	return 1;
+}
+
+static inline void HMAC_CTX_free(HMAC_CTX *ctx)
+{
+	free(ctx);
+}
+
+#endif
+
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L || defined(CRYPT_OPENSSL_DYNAMIC)
+
+static inline void HMAC_CTX_cleanup(HMAC_CTX *ctx)
+{
+	NTLM_UNUSED(ctx);
+}
+
+#endif
+
+
+#ifdef CRYPT_OPENSSL_DYNAMIC
+
+static bool ntlm_crypt_init_functions(ntlm_client *ntlm)
+{
+	void *handle;
+
+	if ((handle = dlopen("libssl.so.1.1", RTLD_NOW)) == NULL &&
+	    (handle = dlopen("libssl.1.1.dylib", RTLD_NOW)) == NULL &&
+	    (handle = dlopen("libssl.so.1.0.0", RTLD_NOW)) == NULL &&
+	    (handle = dlopen("libssl.1.0.0.dylib", RTLD_NOW)) == NULL &&
+	    (handle = dlopen("libssl.so.10", RTLD_NOW)) == NULL) {
+		ntlm_client_set_errmsg(ntlm, "could not open libssl");
+		return false;
+	}
+
+	ntlm->crypt_ctx.des_set_key_fn = dlsym(handle, "DES_set_key");
+	ntlm->crypt_ctx.des_ecb_encrypt_fn = dlsym(handle, "DES_ecb_encrypt");
+	ntlm->crypt_ctx.err_get_error_fn = dlsym(handle, "ERR_get_error");
+	ntlm->crypt_ctx.err_lib_error_string_fn = dlsym(handle, "ERR_lib_error_string");
+	ntlm->crypt_ctx.evp_md5_fn = dlsym(handle, "EVP_md5");
+	ntlm->crypt_ctx.hmac_ctx_new_fn = dlsym(handle, "HMAC_CTX_new");
+	ntlm->crypt_ctx.hmac_ctx_free_fn = dlsym(handle, "HMAC_CTX_free");
+	ntlm->crypt_ctx.hmac_ctx_reset_fn = dlsym(handle, "HMAC_CTX_reset");
+	ntlm->crypt_ctx.hmac_init_ex_fn = dlsym(handle, "HMAC_Init_ex");
+	ntlm->crypt_ctx.hmac_update_fn = dlsym(handle, "HMAC_Update");
+	ntlm->crypt_ctx.hmac_final_fn = dlsym(handle, "HMAC_Final");
+	ntlm->crypt_ctx.md4_fn = dlsym(handle, "MD4");
+	ntlm->crypt_ctx.rand_bytes_fn = dlsym(handle, "RAND_bytes");
+
+	if (!ntlm->crypt_ctx.des_set_key_fn ||
+	    !ntlm->crypt_ctx.des_ecb_encrypt_fn ||
+	    !ntlm->crypt_ctx.err_get_error_fn ||
+	    !ntlm->crypt_ctx.err_lib_error_string_fn ||
+	    !ntlm->crypt_ctx.evp_md5_fn ||
+	    !ntlm->crypt_ctx.hmac_init_ex_fn ||
+	    !ntlm->crypt_ctx.hmac_update_fn ||
+	    !ntlm->crypt_ctx.hmac_final_fn ||
+	    !ntlm->crypt_ctx.md4_fn ||
+	    !ntlm->crypt_ctx.rand_bytes_fn) {
+		ntlm_client_set_errmsg(ntlm, "could not load libssl functions");
+		dlclose(handle);
+		return false;
+	}
+
+	/* Toggle legacy HMAC context functions */
+	if (ntlm->crypt_ctx.hmac_ctx_new_fn &&
+	    ntlm->crypt_ctx.hmac_ctx_free_fn &&
+	    ntlm->crypt_ctx.hmac_ctx_reset_fn) {
+		ntlm->crypt_ctx.hmac_ctx_cleanup_fn = HMAC_CTX_cleanup;
+	} else {
+		ntlm->crypt_ctx.hmac_ctx_cleanup_fn = dlsym(handle, "HMAC_CTX_cleanup");
+
+		if (!ntlm->crypt_ctx.hmac_ctx_cleanup_fn) {
+			ntlm_client_set_errmsg(ntlm, "could not load legacy libssl functions");
+			dlclose(handle);
+			return false;
+		}
+
+		ntlm->crypt_ctx.hmac_ctx_new_fn = HMAC_CTX_new;
+		ntlm->crypt_ctx.hmac_ctx_free_fn = HMAC_CTX_free;
+		ntlm->crypt_ctx.hmac_ctx_reset_fn = HMAC_CTX_reset;
+	}
+
+	ntlm->crypt_ctx.openssl_handle = handle;
+	return true;
+}
+
+#else /* CRYPT_OPENSSL_DYNAMIC */
+
+static bool ntlm_crypt_init_functions(ntlm_client *ntlm)
+{
+	ntlm->crypt_ctx.des_set_key_fn = DES_set_key;
+	ntlm->crypt_ctx.des_ecb_encrypt_fn = DES_ecb_encrypt;
+	ntlm->crypt_ctx.err_get_error_fn = ERR_get_error;
+	ntlm->crypt_ctx.err_lib_error_string_fn = ERR_lib_error_string;
+	ntlm->crypt_ctx.evp_md5_fn = EVP_md5;
+	ntlm->crypt_ctx.hmac_ctx_new_fn = HMAC_CTX_new;
+	ntlm->crypt_ctx.hmac_ctx_free_fn = HMAC_CTX_free;
+	ntlm->crypt_ctx.hmac_ctx_reset_fn = HMAC_CTX_reset;
+	ntlm->crypt_ctx.hmac_ctx_cleanup_fn = HMAC_CTX_cleanup;
+	ntlm->crypt_ctx.hmac_init_ex_fn = HMAC_Init_ex;
+	ntlm->crypt_ctx.hmac_update_fn = HMAC_Update;
+	ntlm->crypt_ctx.hmac_final_fn = HMAC_Final;
+	ntlm->crypt_ctx.md4_fn = MD4;
+	ntlm->crypt_ctx.rand_bytes_fn = RAND_bytes;
+
+	return true;
+}
+
+#endif /* CRYPT_OPENSSL_DYNAMIC */
+
+bool ntlm_crypt_init(ntlm_client *ntlm)
+{
+	if (!ntlm_crypt_init_functions(ntlm))
+		return false;
+
+	ntlm->crypt_ctx.hmac = ntlm->crypt_ctx.hmac_ctx_new_fn();
+
+	if (ntlm->crypt_ctx.hmac == NULL) {
+		ntlm_client_set_errmsg(ntlm, "out of memory");
+		return false;
+	}
+
+	return true;
+}
+
 bool ntlm_random_bytes(
-	ntlm_client *ntlm,
 	unsigned char *out,
+	ntlm_client *ntlm,
 	size_t len)
 {
-	int rc = RAND_bytes(out, len);
+	int rc = ntlm->crypt_ctx.rand_bytes_fn(out, len);
 
 	if (rc != 1) {
-		ntlm_client_set_errmsg(ntlm, ERR_lib_error_string(ERR_get_error()));
+		ntlm_client_set_errmsg(ntlm, ntlm->crypt_ctx.err_lib_error_string_fn(ntlm->crypt_ctx.err_get_error_fn()));
 		return false;
 	}
 
@@ -37,94 +177,81 @@ bool ntlm_random_bytes(
 
 bool ntlm_des_encrypt(
 	ntlm_des_block *out,
+	ntlm_client *ntlm,
 	ntlm_des_block *plaintext,
 	ntlm_des_block *key)
 {
 	DES_key_schedule keysched;
 
+	NTLM_UNUSED(ntlm);
+
 	memset(out, 0, sizeof(ntlm_des_block));
 
-	DES_set_key(key, &keysched);
-	DES_ecb_encrypt(plaintext, out, &keysched, DES_ENCRYPT);
+	ntlm->crypt_ctx.des_set_key_fn(key, &keysched);
+	ntlm->crypt_ctx.des_ecb_encrypt_fn(plaintext, out, &keysched, DES_ENCRYPT);
 
 	return true;
 }
 
 bool ntlm_md4_digest(
 	unsigned char out[CRYPT_MD4_DIGESTSIZE],
+	ntlm_client *ntlm,
 	const unsigned char *in,
 	size_t in_len)
 {
-	MD4(in, in_len, out);
+	ntlm->crypt_ctx.md4_fn(in, in_len, out);
 	return true;
 }
 
-#if OPENSSL_VERSION_NUMBER < 0x10100000L
-static inline void HMAC_CTX_free(HMAC_CTX *ctx)
-{
-	if (ctx)
-		HMAC_CTX_cleanup(ctx);
-
-	free(ctx);
-}
-
-static inline int HMAC_CTX_reset(HMAC_CTX *ctx)
-{
-	HMAC_CTX_cleanup(ctx);
-	ntlm_memzero(ctx, sizeof(HMAC_CTX));
-	return 1;
-}
-
-static inline HMAC_CTX *HMAC_CTX_new(void)
-{
-	return calloc(1, sizeof(HMAC_CTX));
-}
-#endif
-
-ntlm_hmac_ctx *ntlm_hmac_ctx_init(void)
-{
-	return HMAC_CTX_new();
-}
-
-bool ntlm_hmac_ctx_reset(ntlm_hmac_ctx *ctx)
-{
-	return HMAC_CTX_reset(ctx);
-}
-
 bool ntlm_hmac_md5_init(
-	ntlm_hmac_ctx *ctx,
+	ntlm_client *ntlm,
 	const unsigned char *key,
 	size_t key_len)
 {
-	return HMAC_Init_ex(ctx, key, key_len, EVP_md5(), NULL);
+	const EVP_MD *md5 = ntlm->crypt_ctx.evp_md5_fn();
+
+	ntlm->crypt_ctx.hmac_ctx_cleanup_fn(ntlm->crypt_ctx.hmac);
+
+	return ntlm->crypt_ctx.hmac_ctx_reset_fn(ntlm->crypt_ctx.hmac) &&
+	       ntlm->crypt_ctx.hmac_init_ex_fn(ntlm->crypt_ctx.hmac, key, key_len, md5, NULL);
 }
 
 bool ntlm_hmac_md5_update(
-	ntlm_hmac_ctx *ctx,
+	ntlm_client *ntlm,
 	const unsigned char *in,
 	size_t in_len)
 {
-	return HMAC_Update(ctx, in, in_len);
+	return ntlm->crypt_ctx.hmac_update_fn(ntlm->crypt_ctx.hmac, in, in_len);
 }
 
 bool ntlm_hmac_md5_final(
 	unsigned char *out,
 	size_t *out_len,
-	ntlm_hmac_ctx *ctx)
+	ntlm_client *ntlm)
 {
 	unsigned int len;
 
 	if (*out_len < CRYPT_MD5_DIGESTSIZE)
 		return false;
 
-	if (!HMAC_Final(ctx, out, &len))
+	if (!ntlm->crypt_ctx.hmac_final_fn(ntlm->crypt_ctx.hmac, out, &len))
 		return false;
 
 	*out_len = len;
 	return true;
 }
 
-void ntlm_hmac_ctx_free(ntlm_hmac_ctx *ctx)
+void ntlm_crypt_shutdown(ntlm_client *ntlm)
 {
-	HMAC_CTX_free(ctx);
+	if (ntlm->crypt_ctx.hmac) {
+		ntlm->crypt_ctx.hmac_ctx_cleanup_fn(ntlm->crypt_ctx.hmac);
+		ntlm->crypt_ctx.hmac_ctx_free_fn(ntlm->crypt_ctx.hmac);
+	}
+
+#ifdef CRYPT_OPENSSL_DYNAMIC
+	if (ntlm->crypt_ctx.openssl_handle)
+		dlclose(ntlm->crypt_ctx.openssl_handle);
+#endif
+
+	memset(&ntlm->crypt_ctx, 0, sizeof(ntlm_crypt_ctx));
 }
diff --git a/deps/ntlmclient/crypt_openssl.h b/deps/ntlmclient/crypt_openssl.h
index 4195db9a5..8654027db 100644
--- a/deps/ntlmclient/crypt_openssl.h
+++ b/deps/ntlmclient/crypt_openssl.h
@@ -9,13 +9,82 @@
 #ifndef PRIVATE_CRYPT_OPENSSL_H__
 #define PRIVATE_CRYPT_OPENSSL_H__
 
-#include <openssl/hmac.h>
+#ifndef CRYPT_OPENSSL_DYNAMIC
+# include <openssl/des.h>
+# include <openssl/hmac.h>
+#endif
 
 /* OpenSSL 1.1.0 uses opaque structs, we'll reuse these. */
-#if OPENSSL_VERSION_NUMBER < 0x10100000L
-typedef struct hmac_ctx_st ntlm_hmac_ctx;
-#else
-# define ntlm_hmac_ctx HMAC_CTX
+#if defined(OPENSSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER < 0x10100000L
+# define HMAC_CTX struct hmac_ctx_st
+#endif
+
+#ifdef CRYPT_OPENSSL_DYNAMIC
+typedef unsigned char DES_cblock[8];
+typedef unsigned char const_DES_cblock[8];
+
+typedef unsigned long DES_LONG;
+
+typedef struct DES_ks {
+    union {
+        DES_cblock cblock;
+        DES_LONG deslong[2];
+    } ks[16];
+} DES_key_schedule;
+
+#define DES_ENCRYPT 1
+
+typedef void EVP_MD;
+typedef void ENGINE;
+typedef void EVP_PKEY_CTX;
+
+#define HMAC_MAX_MD_CBLOCK 128
+
+typedef struct env_md_ctx_st EVP_MD_CTX;
+struct env_md_ctx_st {
+    const EVP_MD *digest;
+    ENGINE *engine;
+    unsigned long flags;
+    void *md_data;
+    EVP_PKEY_CTX *pctx;
+    int (*update) (EVP_MD_CTX *ctx, const void *data, size_t count);
+};
+
+typedef struct hmac_ctx_st {
+    const EVP_MD *md;
+    EVP_MD_CTX md_ctx;
+    EVP_MD_CTX i_ctx;
+    EVP_MD_CTX o_ctx;
+    unsigned int key_length;
+    unsigned char key[HMAC_MAX_MD_CBLOCK];
+} HMAC_CTX;
 #endif
 
+struct ntlm_crypt_ctx {
+	HMAC_CTX *hmac;
+
+	void *openssl_handle;
+
+	void (*des_ecb_encrypt_fn)(const_DES_cblock *input, DES_cblock *output, DES_key_schedule *ks, int enc);
+	int (*des_set_key_fn)(const_DES_cblock *key, DES_key_schedule *schedule);
+
+	unsigned long (*err_get_error_fn)(void);
+	const char *(*err_lib_error_string_fn)(unsigned long e);
+
+	const EVP_MD *(*evp_md5_fn)(void);
+
+	HMAC_CTX *(*hmac_ctx_new_fn)(void);
+	int (*hmac_ctx_reset_fn)(HMAC_CTX *ctx);
+	void (*hmac_ctx_free_fn)(HMAC_CTX *ctx);
+	void (*hmac_ctx_cleanup_fn)(HMAC_CTX *ctx);
+
+	int (*hmac_init_ex_fn)(HMAC_CTX *ctx, const void *key, int key_len, const EVP_MD *md, ENGINE *impl);
+	int (*hmac_update_fn)(HMAC_CTX *ctx, const unsigned char *data, size_t len);
+	int (*hmac_final_fn)(HMAC_CTX *ctx, unsigned char *md, unsigned int *len);
+
+	unsigned char *(*md4_fn)(const unsigned char *d, size_t n, unsigned char *md);
+
+	int (*rand_bytes_fn)(unsigned char *buf, int num);
+};
+
 #endif /* PRIVATE_CRYPT_OPENSSL_H__ */
diff --git a/deps/ntlmclient/ntlm.c b/deps/ntlmclient/ntlm.c
index 470a90143..3393be915 100644
--- a/deps/ntlmclient/ntlm.c
+++ b/deps/ntlmclient/ntlm.c
@@ -9,7 +9,6 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
-#include <assert.h>
 #include <errno.h>
 #include <ctype.h>
 #include <unistd.h>
@@ -24,6 +23,18 @@
 #include "compat.h"
 #include "util.h"
 
+#define NTLM_ASSERT_ARG(expr) do { \
+		if (!(expr)) \
+			return NTLM_CLIENT_ERROR_INVALID_INPUT; \
+	} while(0)
+
+#define NTLM_ASSERT(ntlm, expr) do { \
+		if (!(expr)) { \
+			ntlm_client_set_errmsg(ntlm, "internal error: " #expr); \
+			return -1; \
+		} \
+	} while(0)
+
 unsigned char ntlm_client_signature[] = NTLM_SIGNATURE;
 
 static bool supports_unicode(ntlm_client *ntlm)
@@ -52,17 +63,20 @@ ntlm_client *ntlm_client_init(ntlm_client_flags flags)
 
 	ntlm->flags = flags;
 
-	if ((ntlm->hmac_ctx = ntlm_hmac_ctx_init()) == NULL ||
-		(ntlm->unicode_ctx = ntlm_unicode_ctx_init(ntlm)) == NULL) {
-		ntlm_hmac_ctx_free(ntlm->hmac_ctx);
-		ntlm_unicode_ctx_free(ntlm->unicode_ctx);
-		free(ntlm);
-		return NULL;
-	}
-
 	return ntlm;
 }
 
+#define ENSURE_INITIALIZED(ntlm) \
+	do { \
+		if (!(ntlm)->unicode_initialized) \
+			(ntlm)->unicode_initialized = ntlm_unicode_init((ntlm)); \
+		if (!(ntlm)->crypt_initialized) \
+			(ntlm)->crypt_initialized = ntlm_crypt_init((ntlm)); \
+		if (!(ntlm)->unicode_initialized || \
+		    !(ntlm)->crypt_initialized) \
+			return -1; \
+	} while(0)
+
 void ntlm_client_set_errmsg(ntlm_client *ntlm, const char *errmsg)
 {
 	ntlm->state = NTLM_STATE_ERROR;
@@ -71,7 +85,9 @@ void ntlm_client_set_errmsg(ntlm_client *ntlm, const char *errmsg)
 
 const char *ntlm_client_errmsg(ntlm_client *ntlm)
 {
-	assert(ntlm);
+	if (!ntlm)
+		return "internal error";
+
 	return ntlm->errmsg ? ntlm->errmsg : "no error";
 }
 
@@ -81,7 +97,7 @@ int ntlm_client_set_version(
 	uint8_t minor,
 	uint16_t build)
 {
-	assert(ntlm);
+	NTLM_ASSERT_ARG(ntlm);
 
 	ntlm->host_version.major = major;
 	ntlm->host_version.minor = minor;
@@ -93,20 +109,25 @@ int ntlm_client_set_version(
 	return 0;
 }
 
+#define reset(ptr) do { free(ptr); ptr = NULL; } while(0)
+
+static void free_hostname(ntlm_client *ntlm)
+{
+	reset(ntlm->hostname);
+	reset(ntlm->hostdomain);
+	reset(ntlm->hostname_utf16);
+	ntlm->hostname_utf16_len = 0;
+}
+
 int ntlm_client_set_hostname(
 	ntlm_client *ntlm,
 	const char *hostname,
 	const char *domain)
 {
-	assert(ntlm);
+	NTLM_ASSERT_ARG(ntlm);
+	ENSURE_INITIALIZED(ntlm);
 
-	free(ntlm->hostname);
-	free(ntlm->hostdomain);
-	free(ntlm->hostname_utf16);
-
-	ntlm->hostname = NULL;
-	ntlm->hostdomain = NULL;
-	ntlm->hostname_utf16 = NULL;
+	free_hostname(ntlm);
 
 	if (hostname && (ntlm->hostname = strdup(hostname)) == NULL) {
 		ntlm_client_set_errmsg(ntlm, "out of memory");
@@ -121,7 +142,7 @@ int ntlm_client_set_hostname(
 	if (hostname && supports_unicode(ntlm) && !ntlm_unicode_utf8_to_16(
 			&ntlm->hostname_utf16,
 			&ntlm->hostname_utf16_len,
-			ntlm->unicode_ctx,
+			ntlm,
 			hostname,
 			strlen(hostname)))
 		return -1;
@@ -137,25 +158,20 @@ static void free_credentials(ntlm_client *ntlm)
 	if (ntlm->password_utf16)
 		ntlm_memzero(ntlm->password_utf16, ntlm->password_utf16_len);
 
-	free(ntlm->username);
-	free(ntlm->username_upper);
-	free(ntlm->userdomain);
-	free(ntlm->password);
-
-	free(ntlm->username_utf16);
-	free(ntlm->username_upper_utf16);
-	free(ntlm->userdomain_utf16);
-	free(ntlm->password_utf16);
-
-	ntlm->username = NULL;
-	ntlm->username_upper = NULL;
-	ntlm->userdomain = NULL;
-	ntlm->password = NULL;
-
-	ntlm->username_utf16 = NULL;
-	ntlm->username_upper_utf16 = NULL;
-	ntlm->userdomain_utf16 = NULL;
-	ntlm->password_utf16 = NULL;
+	reset(ntlm->username);
+	reset(ntlm->username_upper);
+	reset(ntlm->userdomain);
+	reset(ntlm->password);
+
+	reset(ntlm->username_utf16);
+	reset(ntlm->username_upper_utf16);
+	reset(ntlm->userdomain_utf16);
+	reset(ntlm->password_utf16);
+
+	ntlm->username_utf16_len = 0;
+	ntlm->username_upper_utf16_len = 0;
+	ntlm->userdomain_utf16_len = 0;
+	ntlm->password_utf16_len = 0;
 }
 
 int ntlm_client_set_credentials(
@@ -164,7 +180,8 @@ int ntlm_client_set_credentials(
 	const char *domain,
 	const char *password)
 {
-	assert(ntlm);
+	NTLM_ASSERT_ARG(ntlm);
+	ENSURE_INITIALIZED(ntlm);
 
 	free_credentials(ntlm);
 
@@ -185,7 +202,7 @@ int ntlm_client_set_credentials(
 		if (!ntlm_unicode_utf8_to_16(
 				&ntlm->username_utf16,
 				&ntlm->username_utf16_len,
-				ntlm->unicode_ctx,
+				ntlm,
 				ntlm->username,
 				strlen(ntlm->username)))
 			return -1;
@@ -193,7 +210,7 @@ int ntlm_client_set_credentials(
 		if (!ntlm_unicode_utf8_to_16(
 				&ntlm->username_upper_utf16,
 				&ntlm->username_upper_utf16_len,
-				ntlm->unicode_ctx,
+				ntlm,
 				ntlm->username_upper,
 				strlen(ntlm->username_upper)))
 			return -1;
@@ -202,7 +219,7 @@ int ntlm_client_set_credentials(
 	if (domain && supports_unicode(ntlm) && !ntlm_unicode_utf8_to_16(
 			&ntlm->userdomain_utf16,
 			&ntlm->userdomain_utf16_len,
-			ntlm->unicode_ctx,
+			ntlm,
 			ntlm->userdomain,
 			strlen(ntlm->userdomain)))
 		return -1;
@@ -212,7 +229,8 @@ int ntlm_client_set_credentials(
 
 int ntlm_client_set_target(ntlm_client *ntlm, const char *target)
 {
-	assert(ntlm);
+	NTLM_ASSERT_ARG(ntlm);
+	ENSURE_INITIALIZED(ntlm);
 
 	free(ntlm->target);
 	free(ntlm->target_utf16);
@@ -229,7 +247,7 @@ int ntlm_client_set_target(ntlm_client *ntlm, const char *target)
 		if (supports_unicode(ntlm) && !ntlm_unicode_utf8_to_16(
 				&ntlm->target_utf16,
 				&ntlm->target_utf16_len,
-				ntlm->unicode_ctx,
+				ntlm,
 				ntlm->target,
 				strlen(ntlm->target)))
 			return -1;
@@ -240,14 +258,16 @@ int ntlm_client_set_target(ntlm_client *ntlm, const char *target)
 
 int ntlm_client_set_nonce(ntlm_client *ntlm, uint64_t nonce)
 {
-	assert(ntlm);
+	NTLM_ASSERT_ARG(ntlm);
+
 	ntlm->nonce = nonce;
 	return 0;
 }
 
 int ntlm_client_set_timestamp(ntlm_client *ntlm, uint64_t timestamp)
 {
-	assert(ntlm);
+	NTLM_ASSERT_ARG(ntlm);
+
 	ntlm->timestamp = timestamp;
 	return 0;
 }
@@ -475,7 +495,7 @@ static inline bool read_string_unicode(
 	size_t out_len;
 	int ret = ntlm_unicode_utf16_to_8(out,
 		&out_len,
-		ntlm->unicode_ctx,
+		ntlm,
 		(char *)&message->buf[message->pos],
 		string_len);
 
@@ -593,7 +613,9 @@ int ntlm_client_negotiate(
 	size_t hostname_offset = 0;
 	uint32_t flags = 0;
 
-	assert(out && out_len && ntlm);
+	NTLM_ASSERT_ARG(out);
+	NTLM_ASSERT_ARG(out_len);
+	NTLM_ASSERT_ARG(ntlm);
 
 	*out = NULL;
 	*out_len = 0;
@@ -676,20 +698,22 @@ int ntlm_client_negotiate(
 		return -1;
 
 	if (hostname_len > 0) {
-		assert(hostname_offset == ntlm->negotiate.pos);
+		NTLM_ASSERT(ntlm, hostname_offset == ntlm->negotiate.pos);
+
 		if (!write_buf(ntlm, &ntlm->negotiate,
 			(const unsigned char *)ntlm->hostname, hostname_len))
 			return -1;
 	}
 
 	if (domain_len > 0) {
-		assert(domain_offset == ntlm->negotiate.pos);
+		NTLM_ASSERT(ntlm, domain_offset == ntlm->negotiate.pos);
+
 		if (!write_buf(ntlm, &ntlm->negotiate,
 			(const unsigned char *)ntlm->hostdomain, domain_len))
 			return -1;
 	}
 
-	assert(ntlm->negotiate.pos == ntlm->negotiate.len);
+	NTLM_ASSERT(ntlm, ntlm->negotiate.pos == ntlm->negotiate.len);
 
 	ntlm->state = NTLM_STATE_CHALLENGE;
 
@@ -711,7 +735,10 @@ int ntlm_client_set_challenge(
 	uint32_t name_offset, info_offset = 0;
 	bool unicode, has_target_info = false;
 
-	assert(ntlm && (challenge_msg || !challenge_msg_len));
+	NTLM_ASSERT_ARG(ntlm);
+	NTLM_ASSERT_ARG(challenge_msg || !challenge_msg_len);
+
+	ENSURE_INITIALIZED(ntlm);
 
 	if (ntlm->state != NTLM_STATE_NEGOTIATE &&
 		ntlm->state != NTLM_STATE_CHALLENGE) {
@@ -940,6 +967,7 @@ static void des_key_from_password(
 
 static inline bool generate_lm_hash(
 	ntlm_des_block out[2],
+	ntlm_client *ntlm,
 	const char *password)
 {
 	/* LM encrypts this known plaintext using the password as a key */
@@ -968,8 +996,8 @@ static inline bool generate_lm_hash(
 	des_key_from_password(&key1, keystr1, keystr1_len);
 	des_key_from_password(&key2, keystr2, keystr2_len);
 
-	return ntlm_des_encrypt(&out[0], &plaintext, &key1) &&
-		ntlm_des_encrypt(&out[1], &plaintext, &key2);
+	return ntlm_des_encrypt(&out[0], ntlm, &plaintext, &key1) &&
+		ntlm_des_encrypt(&out[1], ntlm, &plaintext, &key2);
 }
 
 static void des_keys_from_lm_hash(ntlm_des_block out[3], ntlm_des_block lm_hash[2])
@@ -994,16 +1022,16 @@ static bool generate_lm_response(ntlm_client *ntlm)
 	ntlm_des_block *challenge = (ntlm_des_block *)&ntlm->challenge.nonce;
 
 	/* Generate the LM hash from the password */
-	if (!generate_lm_hash(lm_hash, ntlm->password))
+	if (!generate_lm_hash(lm_hash, ntlm, ntlm->password))
 		return false;
 
 	/* Convert that LM hash to three DES keys */
 	des_keys_from_lm_hash(key, lm_hash);
 
 	/* Finally, encrypt the challenge with each of these keys */
-	if (!ntlm_des_encrypt(&lm_response[0], challenge, &key[0]) ||
-		!ntlm_des_encrypt(&lm_response[1], challenge, &key[1]) ||
-		!ntlm_des_encrypt(&lm_response[2], challenge, &key[2]))
+	if (!ntlm_des_encrypt(&lm_response[0], ntlm, challenge, &key[0]) ||
+		!ntlm_des_encrypt(&lm_response[1], ntlm, challenge, &key[1]) ||
+		!ntlm_des_encrypt(&lm_response[2], ntlm, challenge, &key[2]))
 		return false;
 
 	memcpy(&ntlm->lm_response[0], lm_response[0], 8);
@@ -1022,12 +1050,13 @@ static bool generate_ntlm_hash(
 	if (ntlm->password && !ntlm_unicode_utf8_to_16(
 			&ntlm->password_utf16,
 			&ntlm->password_utf16_len,
-			ntlm->unicode_ctx,
+			ntlm,
 			ntlm->password,
 			strlen(ntlm->password)))
 		return false;
 
 	return ntlm_md4_digest(out,
+		ntlm,
 		(const unsigned char *)ntlm->password_utf16,
 		ntlm->password_utf16_len);
 }
@@ -1048,9 +1077,9 @@ static bool generate_ntlm_response(ntlm_client *ntlm)
 	des_key_from_password(&key[2], &ntlm_hash[14], 2);
 
 	/* Finally, encrypt the challenge with each of these keys */
-	if (!ntlm_des_encrypt(&ntlm_response[0], challenge, &key[0]) ||
-		!ntlm_des_encrypt(&ntlm_response[1], challenge, &key[1]) ||
-		!ntlm_des_encrypt(&ntlm_response[2], challenge, &key[2]))
+	if (!ntlm_des_encrypt(&ntlm_response[0], ntlm, challenge, &key[0]) ||
+		!ntlm_des_encrypt(&ntlm_response[1], ntlm, challenge, &key[1]) ||
+		!ntlm_des_encrypt(&ntlm_response[2], ntlm, challenge, &key[2]))
 		return false;
 
 	memcpy(&ntlm->ntlm_response[0], ntlm_response[0], 8);
@@ -1081,16 +1110,15 @@ static bool generate_ntlm2_hash(
 		target_len = ntlm->target_utf16_len;
 	}
 
-	if (!ntlm_hmac_ctx_reset(ntlm->hmac_ctx) ||
-		!ntlm_hmac_md5_init(ntlm->hmac_ctx, ntlm_hash, sizeof(ntlm_hash)) ||
-		!ntlm_hmac_md5_update(ntlm->hmac_ctx, username, username_len) ||
-		!ntlm_hmac_md5_update(ntlm->hmac_ctx, target, target_len) ||
-		!ntlm_hmac_md5_final(out, &out_len, ntlm->hmac_ctx)) {
+	if (!ntlm_hmac_md5_init(ntlm, ntlm_hash, sizeof(ntlm_hash)) ||
+		!ntlm_hmac_md5_update(ntlm, username, username_len) ||
+		!ntlm_hmac_md5_update(ntlm, target, target_len) ||
+		!ntlm_hmac_md5_final(out, &out_len, ntlm)) {
 		ntlm_client_set_errmsg(ntlm, "failed to create HMAC-MD5");
 		return false;
 	}
 
-	assert(out_len == NTLM_NTLM2_HASH_LEN);
+	NTLM_ASSERT(ntlm, out_len == NTLM_NTLM2_HASH_LEN);
 	return true;
 }
 
@@ -1103,18 +1131,15 @@ static bool generate_ntlm2_challengehash(
 {
 	size_t out_len = 16;
 
-	if (!ntlm_hmac_ctx_reset(ntlm->hmac_ctx) ||
-		!ntlm_hmac_md5_init(ntlm->hmac_ctx,
-			ntlm2_hash, NTLM_NTLM2_HASH_LEN) ||
-		!ntlm_hmac_md5_update(ntlm->hmac_ctx,
-			(const unsigned char *)&ntlm->challenge.nonce, 8) ||
-		!ntlm_hmac_md5_update(ntlm->hmac_ctx, blob, blob_len) ||
-		!ntlm_hmac_md5_final(out, &out_len, ntlm->hmac_ctx)) {
+	if (!ntlm_hmac_md5_init(ntlm, ntlm2_hash, NTLM_NTLM2_HASH_LEN) ||
+		!ntlm_hmac_md5_update(ntlm, (const unsigned char *)&ntlm->challenge.nonce, 8) ||
+		!ntlm_hmac_md5_update(ntlm, blob, blob_len) ||
+		!ntlm_hmac_md5_final(out, &out_len, ntlm)) {
 		ntlm_client_set_errmsg(ntlm, "failed to create HMAC-MD5");
 		return false;
 	}
 
-	assert(out_len == 16);
+	NTLM_ASSERT(ntlm, out_len == 16);
 	return true;
 }
 
@@ -1127,19 +1152,15 @@ static bool generate_lm2_response(ntlm_client *ntlm,
 
 	local_nonce = ntlm_htonll(ntlm->nonce);
 
-	if (!ntlm_hmac_ctx_reset(ntlm->hmac_ctx) ||
-		!ntlm_hmac_md5_init(ntlm->hmac_ctx,
-			ntlm2_hash, NTLM_NTLM2_HASH_LEN) ||
-		!ntlm_hmac_md5_update(ntlm->hmac_ctx,
-			(const unsigned char *)&ntlm->challenge.nonce, 8) ||
-		!ntlm_hmac_md5_update(ntlm->hmac_ctx,
-			(const unsigned char *)&local_nonce, 8) ||
-		!ntlm_hmac_md5_final(lm2_challengehash, &lm2_len, ntlm->hmac_ctx)) {
+	if (!ntlm_hmac_md5_init(ntlm, ntlm2_hash, NTLM_NTLM2_HASH_LEN) ||
+		!ntlm_hmac_md5_update(ntlm, (const unsigned char *)&ntlm->challenge.nonce, 8) ||
+		!ntlm_hmac_md5_update(ntlm, (const unsigned char *)&local_nonce, 8) ||
+		!ntlm_hmac_md5_final(lm2_challengehash, &lm2_len, ntlm)) {
 		ntlm_client_set_errmsg(ntlm, "failed to create HMAC-MD5");
 		return false;
 	}
 
-	assert(lm2_len == 16);
+	NTLM_ASSERT(ntlm, lm2_len == 16);
 
 	memcpy(&ntlm->lm_response[0], lm2_challengehash, 16);
 	memcpy(&ntlm->lm_response[16], &local_nonce, 8);
@@ -1163,7 +1184,7 @@ static bool generate_nonce(ntlm_client *ntlm)
 	if (ntlm->nonce)
 		return true;
 
-	if (!ntlm_random_bytes(ntlm, buf, 8))
+	if (!ntlm_random_bytes(buf, ntlm, 8))
 		return false;
 
 	memcpy(&ntlm->nonce, buf, sizeof(uint64_t));
@@ -1233,7 +1254,11 @@ int ntlm_client_response(
 	uint32_t flags = 0;
 	bool unicode;
 
-	assert(out && out_len && ntlm);
+	NTLM_ASSERT_ARG(out);
+	NTLM_ASSERT_ARG(out_len);
+	NTLM_ASSERT_ARG(ntlm);
+
+	ENSURE_INITIALIZED(ntlm);
 
 	*out = NULL;
 	*out_len = 0;
@@ -1356,7 +1381,7 @@ int ntlm_client_response(
 		!write_buf(ntlm, &ntlm->response, session, session_len))
 		return -1;
 
-	assert(ntlm->response.pos == ntlm->response.len);
+	NTLM_ASSERT(ntlm, ntlm->response.pos == ntlm->response.len);
 
 	ntlm->state = NTLM_STATE_COMPLETE;
 
@@ -1368,41 +1393,48 @@ int ntlm_client_response(
 
 void ntlm_client_reset(ntlm_client *ntlm)
 {
-	ntlm_client_flags flags;
-	ntlm_hmac_ctx *hmac_ctx;
-	ntlm_unicode_ctx *unicode_ctx;
-
-	assert(ntlm);
+	if (!ntlm)
+		return;
 
-	free(ntlm->negotiate.buf);
-	free(ntlm->challenge.target_info);
-	free(ntlm->challenge.target);
-	free(ntlm->challenge.target_domain);
-	free(ntlm->challenge.target_domain_dns);
-	free(ntlm->challenge.target_server);
-	free(ntlm->challenge.target_server_dns);
-	free(ntlm->response.buf);
+	ntlm->state = NTLM_STATE_NEGOTIATE;
 
-	free(ntlm->hostname);
-	free(ntlm->hostname_utf16);
-	free(ntlm->hostdomain);
+	free_hostname(ntlm);
 
-	free(ntlm->target);
-	free(ntlm->target_utf16);
+	memset(&ntlm->host_version, 0, sizeof(ntlm_version));
 
-	free(ntlm->ntlm2_response);
+	reset(ntlm->target);
+	reset(ntlm->target_utf16);
+	ntlm->target_utf16_len = 0;
 
 	free_credentials(ntlm);
 
-	flags = ntlm->flags;
-	hmac_ctx = ntlm->hmac_ctx;
-	unicode_ctx = ntlm->unicode_ctx;
+	ntlm->nonce = 0;
+	ntlm->timestamp = 0;
 
-	memset(ntlm, 0, sizeof(struct ntlm_client));
+	memset(ntlm->lm_response, 0, NTLM_LM_RESPONSE_LEN);
+	ntlm->lm_response_len = 0;
 
-	ntlm->flags = flags;
-	ntlm->hmac_ctx = hmac_ctx;
-	ntlm->unicode_ctx = unicode_ctx;
+	memset(ntlm->ntlm_response, 0, NTLM_NTLM_RESPONSE_LEN);
+	ntlm->ntlm_response_len = 0;
+
+	reset(ntlm->ntlm2_response);
+	ntlm->ntlm2_response_len = 0;
+
+	reset(ntlm->negotiate.buf);
+	ntlm->negotiate.pos = 0;
+	ntlm->negotiate.len = 0;
+
+	reset(ntlm->response.buf);
+	ntlm->response.pos = 0;
+	ntlm->response.len = 0;
+
+	free(ntlm->challenge.target_info);
+	free(ntlm->challenge.target);
+	free(ntlm->challenge.target_domain);
+	free(ntlm->challenge.target_domain_dns);
+	free(ntlm->challenge.target_server);
+	free(ntlm->challenge.target_server_dns);
+	memset(&ntlm->challenge, 0, sizeof(ntlm_challenge));
 }
 
 void ntlm_client_free(ntlm_client *ntlm)
@@ -1410,10 +1442,10 @@ void ntlm_client_free(ntlm_client *ntlm)
 	if (!ntlm)
 		return;
 
-	ntlm_client_reset(ntlm);
+	ntlm_crypt_shutdown(ntlm);
+	ntlm_unicode_shutdown(ntlm);
 
-	ntlm_hmac_ctx_free(ntlm->hmac_ctx);
-	ntlm_unicode_ctx_free(ntlm->unicode_ctx);
+	ntlm_client_reset(ntlm);
 
 	free(ntlm);
 }
diff --git a/deps/ntlmclient/ntlm.h b/deps/ntlmclient/ntlm.h
index 0dad91ec0..227f5bcba 100644
--- a/deps/ntlmclient/ntlm.h
+++ b/deps/ntlmclient/ntlm.h
@@ -14,6 +14,8 @@
 #include "crypt.h"
 #include "compat.h"
 
+#define NTLM_UNUSED(x) ((void)(x))
+
 #define NTLM_LM_RESPONSE_LEN 24
 #define NTLM_NTLM_RESPONSE_LEN 24
 #define NTLM_NTLM_HASH_LEN 16
@@ -66,9 +68,11 @@ struct ntlm_client {
 
 	ntlm_state state;
 
-	/* crypto contexts */
-	ntlm_hmac_ctx *hmac_ctx;
-	ntlm_unicode_ctx *unicode_ctx;
+	/* subsystem contexts */
+	ntlm_crypt_ctx crypt_ctx;
+	ntlm_unicode_ctx unicode_ctx;
+	int crypt_initialized : 1,
+	    unicode_initialized : 1;
 
 	/* error message as set by the library */
 	const char *errmsg;
@@ -85,24 +89,24 @@ struct ntlm_client {
 	char *password;
 
 	/* strings as converted to utf16 */
+	char *hostname_utf16;
 	char *target_utf16;
 	char *username_utf16;
 	char *username_upper_utf16;
 	char *userdomain_utf16;
-	char *hostname_utf16;
 	char *password_utf16;
 
-	/* timestamp and nonce; only for debugging */
-	uint64_t nonce;
-	uint64_t timestamp;
-
+	size_t hostname_utf16_len;
 	size_t username_utf16_len;
 	size_t username_upper_utf16_len;
 	size_t userdomain_utf16_len;
-	size_t hostname_utf16_len;
 	size_t password_utf16_len;
 	size_t target_utf16_len;
 
+	/* timestamp and nonce; only for debugging */
+	uint64_t nonce;
+	uint64_t timestamp;
+
 	unsigned char lm_response[NTLM_LM_RESPONSE_LEN];
 	size_t lm_response_len;
 
diff --git a/deps/ntlmclient/ntlmclient.h b/deps/ntlmclient/ntlmclient.h
index d109a5c89..bf57b17c6 100644
--- a/deps/ntlmclient/ntlmclient.h
+++ b/deps/ntlmclient/ntlmclient.h
@@ -15,13 +15,26 @@
 extern "C" {
 #endif
 
-#define NTLM_CLIENT_VERSION         "0.0.1"
+#define NTLM_CLIENT_VERSION         "0.9.0"
 #define NTLM_CLIENT_VERSION_MAJOR   0
-#define NTLM_CLIENT_VERSION_MINOR   0
-#define NTLM_CLIENT_VERSION_TEENY   1
+#define NTLM_CLIENT_VERSION_MINOR   9
+#define NTLM_CLIENT_VERSION_TEENY   0
 
 typedef struct ntlm_client ntlm_client;
 
+typedef enum {
+	/**
+	 * An error occurred; more details are available by querying
+	 * `ntlm_client_errmsg`.
+	 */
+	NTLM_CLIENT_ERROR = -1,
+
+	/**
+	 * The input provided to the function is missing or invalid.
+	 */
+	NTLM_CLIENT_ERROR_INVALID_INPUT = -2,
+} ntlm_error_code;
+
 /*
  * Flags for initializing the `ntlm_client` context.  A combination of
  * these flags can be provided to `ntlm_client_init`.
diff --git a/deps/ntlmclient/unicode.h b/deps/ntlmclient/unicode.h
index e3b17bcf7..b7c63f2ed 100644
--- a/deps/ntlmclient/unicode.h
+++ b/deps/ntlmclient/unicode.h
@@ -11,26 +11,32 @@
 
 #include "compat.h"
 
+#ifdef UNICODE_ICONV
+# include "unicode_iconv.h"
+#elif UNICODE_BUILTIN
+# include "unicode_builtin.h"
+#endif
+
 #define NTLM_UNICODE_MAX_LEN	2048
 
 typedef struct ntlm_unicode_ctx ntlm_unicode_ctx;
 
-extern ntlm_unicode_ctx *ntlm_unicode_ctx_init(ntlm_client *ntlm);
+extern bool ntlm_unicode_init(ntlm_client *ntlm);
 
 bool ntlm_unicode_utf8_to_16(
 	char **converted,
 	size_t *converted_len,
-	ntlm_unicode_ctx *ctx,
+	ntlm_client *ntlm,
 	const char *string,
 	size_t string_len);
 
 bool ntlm_unicode_utf16_to_8(
 	char **converted,
 	size_t *converted_len,
-	ntlm_unicode_ctx *ctx,
+	ntlm_client *ntlm,
 	const char *string,
 	size_t string_len);
 
-extern void ntlm_unicode_ctx_free(ntlm_unicode_ctx *ctx);
+extern void ntlm_unicode_shutdown(ntlm_client *ntlm);
 
 #endif /* PRIVATE_UNICODE_H__ */
diff --git a/deps/ntlmclient/unicode_builtin.c b/deps/ntlmclient/unicode_builtin.c
index e1856cca9..e2ee0abf7 100644
--- a/deps/ntlmclient/unicode_builtin.c
+++ b/deps/ntlmclient/unicode_builtin.c
@@ -13,10 +13,6 @@
 #include "unicode.h"
 #include "compat.h"
 
-struct ntlm_unicode_ctx {
-	ntlm_client *ntlm;
-};
-
 typedef unsigned int    UTF32;   /* at least 32 bits */
 typedef unsigned short  UTF16;   /* at least 16 bits */
 typedef unsigned char   UTF8;    /* typically 8 bits */
@@ -281,15 +277,10 @@ static ConversionResult ConvertUTF8toUTF16 (
 }
 
 
-ntlm_unicode_ctx *ntlm_unicode_ctx_init(ntlm_client *ntlm)
+bool ntlm_unicode_init(ntlm_client *ntlm)
 {
-	ntlm_unicode_ctx *ctx;
-
-	if ((ctx = malloc(sizeof(ntlm_unicode_ctx))) == NULL)
-		return NULL;
-
-	ctx->ntlm = ntlm;
-	return ctx;
+	NTLM_UNUSED(ntlm);
+	return true;
 }
 
 typedef enum {
@@ -300,7 +291,7 @@ typedef enum {
 static inline bool unicode_builtin_encoding_convert(
 	char **converted,
 	size_t *converted_len,
-	ntlm_unicode_ctx *ctx,
+	ntlm_client *ntlm,
 	const char *string,
 	size_t string_len,
 	unicode_builtin_encoding_direction direction)
@@ -332,7 +323,7 @@ static inline bool unicode_builtin_encoding_convert(
 	out_size = (out_size + 7) & ~7;
 
 	if ((out = malloc(out_size)) == NULL) {
-		ntlm_client_set_errmsg(ctx->ntlm, "out of memory");
+		ntlm_client_set_errmsg(ntlm, "out of memory");
 		return false;
 	}
 
@@ -358,17 +349,17 @@ static inline bool unicode_builtin_encoding_convert(
 				success = true;
 				goto done;
 			case sourceExhausted:
-				ntlm_client_set_errmsg(ctx->ntlm,
+				ntlm_client_set_errmsg(ntlm,
 					"invalid unicode string; trailing data remains");
 				goto done;
 			case targetExhausted:
 				break;
 			case sourceIllegal:
-				ntlm_client_set_errmsg(ctx->ntlm,
+				ntlm_client_set_errmsg(ntlm,
 					"invalid unicode string; trailing data remains");
 				goto done;
 			default:
-				ntlm_client_set_errmsg(ctx->ntlm,
+				ntlm_client_set_errmsg(ntlm,
 					"unknown unicode conversion failure");
 				goto done;
 		}
@@ -377,13 +368,12 @@ static inline bool unicode_builtin_encoding_convert(
 		out_size = ((((out_size << 1) - (out_size >> 1)) + 7) & ~7);
 
 		if (out_size > NTLM_UNICODE_MAX_LEN) {
-			ntlm_client_set_errmsg(ctx->ntlm,
-				"unicode conversion too large");
+			ntlm_client_set_errmsg(ntlm, "unicode conversion too large");
 			goto done;
 		}
 
 		if ((new_out = realloc(out, out_size)) == NULL) {
-			ntlm_client_set_errmsg(ctx->ntlm, "out of memory");
+			ntlm_client_set_errmsg(ntlm, "out of memory");
 			goto done;
 		}
 
@@ -419,27 +409,26 @@ done:
 bool ntlm_unicode_utf8_to_16(
 	char **converted,
 	size_t *converted_len,
-	ntlm_unicode_ctx *ctx,
+	ntlm_client *client,
 	const char *string,
 	size_t string_len)
 {
 	return unicode_builtin_encoding_convert(converted, converted_len,
-		ctx, string, string_len, unicode_builtin_utf8_to_16);
+		client, string, string_len, unicode_builtin_utf8_to_16);
 }
 
 bool ntlm_unicode_utf16_to_8(
 	char **converted,
 	size_t *converted_len,
-	ntlm_unicode_ctx *ctx,
+	ntlm_client *client,
 	const char *string,
 	size_t string_len)
 {
 	return unicode_builtin_encoding_convert(converted, converted_len,
-		ctx, string, string_len, unicode_builtin_utf16_to_8);
+		client, string, string_len, unicode_builtin_utf16_to_8);
 }
 
-void ntlm_unicode_ctx_free(ntlm_unicode_ctx *ctx)
+void ntlm_unicode_shutdown(ntlm_client *ntlm)
 {
-	if (ctx)
-		free(ctx);
+	NTLM_UNUSED(ntlm);
 }
diff --git a/deps/ntlmclient/unicode_builtin.h b/deps/ntlmclient/unicode_builtin.h
new file mode 100644
index 000000000..eabec40bf
--- /dev/null
+++ b/deps/ntlmclient/unicode_builtin.h
@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) Edward Thomson.  All rights reserved.
+ *
+ * This file is part of ntlmclient, distributed under the MIT license.
+ * For full terms and copyright information, and for third-party
+ * copyright information, see the included LICENSE.txt file.
+ */
+
+#ifndef PRIVATE_UNICODE_BUILTIN_H__
+#define PRIVATE_UNICODE_BUILTIN_H__
+
+#include <locale.h>
+#include <iconv.h>
+
+#include "ntlmclient.h"
+
+struct ntlm_unicode_ctx {
+};
+
+#endif /* PRIVATE_UNICODE_BUILTIN_H__ */
diff --git a/deps/ntlmclient/unicode_iconv.c b/deps/ntlmclient/unicode_iconv.c
index d1fe07e26..e14da21f5 100644
--- a/deps/ntlmclient/unicode_iconv.c
+++ b/deps/ntlmclient/unicode_iconv.c
@@ -16,43 +16,23 @@
 #include "ntlm.h"
 #include "compat.h"
 
-struct ntlm_unicode_ctx {
-	ntlm_client *ntlm;
-	iconv_t utf8_to_16;
-	iconv_t utf16_to_8;
-};
-
-ntlm_unicode_ctx *ntlm_unicode_ctx_init(ntlm_client *ntlm)
-{
-	ntlm_unicode_ctx *ctx;
-
-	if ((ctx = calloc(1, sizeof(ntlm_unicode_ctx))) == NULL)
-		return NULL;
-
-	ctx->ntlm = ntlm;
-	ctx->utf8_to_16 = (iconv_t)-1;
-	ctx->utf16_to_8 = (iconv_t)-1;
-
-	return ctx;
-}
-
 typedef enum {
 	unicode_iconv_utf8_to_16,
 	unicode_iconv_utf16_to_8
 } unicode_iconv_encoding_direction;
 
-static inline bool unicode_iconv_init(ntlm_unicode_ctx *ctx)
+bool ntlm_unicode_init(ntlm_client *ntlm)
 {
-	if (ctx->utf8_to_16 != (iconv_t)-1 || ctx->utf16_to_8 != (iconv_t)-1)
-		return true;
+	ntlm->unicode_ctx.utf8_to_16 = iconv_open("UTF-16LE", "UTF-8");
+	ntlm->unicode_ctx.utf16_to_8 = iconv_open("UTF-8", "UTF-16LE");
 
-	if ((ctx->utf8_to_16 = iconv_open("UTF-16LE", "UTF-8")) == (iconv_t)-1 ||
-		(ctx->utf16_to_8 = iconv_open("UTF-8", "UTF-16LE")) == (iconv_t)-1) {
+	if (ntlm->unicode_ctx.utf8_to_16 == (iconv_t)-1 ||
+	    ntlm->unicode_ctx.utf16_to_8 == (iconv_t)-1) {
 		if (errno == EINVAL)
-			ntlm_client_set_errmsg(ctx->ntlm,
+			ntlm_client_set_errmsg(ntlm,
 				"iconv does not support UTF8 <-> UTF16 conversion");
 		else
-			ntlm_client_set_errmsg(ctx->ntlm, strerror(errno));
+			ntlm_client_set_errmsg(ntlm, strerror(errno));
 
 		return false;
 	}
@@ -63,7 +43,7 @@ static inline bool unicode_iconv_init(ntlm_unicode_ctx *ctx)
 static inline bool unicode_iconv_encoding_convert(
 	char **converted,
 	size_t *converted_len,
-	ntlm_unicode_ctx *ctx,
+	ntlm_client *ntlm,
 	const char *string,
 	size_t string_len,
 	unicode_iconv_encoding_direction direction)
@@ -75,9 +55,6 @@ static inline bool unicode_iconv_encoding_convert(
 	*converted = NULL;
 	*converted_len = 0;
 
-	if (!unicode_iconv_init(ctx))
-		return false;
-
 	/*
 	 * When translating UTF8 to UTF16, these strings are only used
 	 * internally, and we obey the given length, so we can simply
@@ -86,11 +63,11 @@ static inline bool unicode_iconv_encoding_convert(
 	 * terminate and expect an extra byte for UTF8, two for UTF16.
 	 */
 	if (direction == unicode_iconv_utf8_to_16) {
-		converter = ctx->utf8_to_16;
+		converter = ntlm->unicode_ctx.utf8_to_16;
 		out_size = (string_len * 2) + 2;
 		nul_size = 2;
 	} else {
-		converter = ctx->utf16_to_8;
+		converter = ntlm->unicode_ctx.utf16_to_8;
 		out_size = (string_len / 2) + 1;
 		nul_size = 1;
 	}
@@ -99,7 +76,7 @@ static inline bool unicode_iconv_encoding_convert(
 	out_size = (out_size + 7) & ~7;
 
 	if ((out = malloc(out_size)) == NULL) {
-		ntlm_client_set_errmsg(ctx->ntlm, "out of memory");
+		ntlm_client_set_errmsg(ntlm, "out of memory");
 		return false;
 	}
 
@@ -117,7 +94,7 @@ static inline bool unicode_iconv_encoding_convert(
 			break;
 
 		if (ret == (size_t)-1 && errno != E2BIG) {
-			ntlm_client_set_errmsg(ctx->ntlm, strerror(errno));
+			ntlm_client_set_errmsg(ntlm, strerror(errno));
 			goto on_error;
 		}
 
@@ -125,13 +102,12 @@ static inline bool unicode_iconv_encoding_convert(
 		out_size = ((((out_size << 1) - (out_size >> 1)) + 7) & ~7);
 
 		if (out_size > NTLM_UNICODE_MAX_LEN) {
-			ntlm_client_set_errmsg(ctx->ntlm,
-				"unicode conversion too large");
+			ntlm_client_set_errmsg(ntlm, "unicode conversion too large");
 			goto on_error;
 		}
 
 		if ((new_out = realloc(out, out_size)) == NULL) {
-			ntlm_client_set_errmsg(ctx->ntlm, "out of memory");
+			ntlm_client_set_errmsg(ntlm, "out of memory");
 			goto on_error;
 		}
 
@@ -139,7 +115,7 @@ static inline bool unicode_iconv_encoding_convert(
 	}
 
 	if (in_start_len != 0) {
-		ntlm_client_set_errmsg(ctx->ntlm,
+		ntlm_client_set_errmsg(ntlm,
 			"invalid unicode string; trailing data remains");
 		goto on_error;
 	}
@@ -165,37 +141,37 @@ on_error:
 bool ntlm_unicode_utf8_to_16(
 	char **converted,
 	size_t *converted_len,
-	ntlm_unicode_ctx *ctx,
+	ntlm_client *ntlm,
 	const char *string,
 	size_t string_len)
 {
 	return unicode_iconv_encoding_convert(
-		converted, converted_len, ctx, string, string_len,
+		converted, converted_len, ntlm, string, string_len,
 		unicode_iconv_utf8_to_16);
 }
 
 bool ntlm_unicode_utf16_to_8(
 	char **converted,
 	size_t *converted_len,
-	ntlm_unicode_ctx *ctx,
+	ntlm_client *ntlm,
 	const char *string,
 	size_t string_len)
 {
 	return unicode_iconv_encoding_convert(
-		converted, converted_len, ctx, string, string_len,
+		converted, converted_len, ntlm, string, string_len,
 		unicode_iconv_utf16_to_8);
 }
 
-void ntlm_unicode_ctx_free(ntlm_unicode_ctx *ctx)
+void ntlm_unicode_shutdown(ntlm_client *ntlm)
 {
-	if (!ctx)
-		return;
-
-	if (ctx->utf16_to_8 != (iconv_t)-1)
-		iconv_close(ctx->utf16_to_8);
+	if (ntlm->unicode_ctx.utf16_to_8 != (iconv_t)0 &&
+	    ntlm->unicode_ctx.utf16_to_8 != (iconv_t)-1)
+		iconv_close(ntlm->unicode_ctx.utf16_to_8);
 
-	if (ctx->utf8_to_16 != (iconv_t)-1)
-		iconv_close(ctx->utf8_to_16);
+	if (ntlm->unicode_ctx.utf8_to_16 != (iconv_t)0 &&
+	    ntlm->unicode_ctx.utf8_to_16 != (iconv_t)-1)
+		iconv_close(ntlm->unicode_ctx.utf8_to_16);
 
-	free(ctx);
+	ntlm->unicode_ctx.utf8_to_16 = (iconv_t)-1;
+	ntlm->unicode_ctx.utf16_to_8 = (iconv_t)-1;
 }
diff --git a/deps/ntlmclient/unicode_iconv.h b/deps/ntlmclient/unicode_iconv.h
new file mode 100644
index 000000000..87a96a67d
--- /dev/null
+++ b/deps/ntlmclient/unicode_iconv.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) Edward Thomson.  All rights reserved.
+ *
+ * This file is part of ntlmclient, distributed under the MIT license.
+ * For full terms and copyright information, and for third-party
+ * copyright information, see the included LICENSE.txt file.
+ */
+
+#ifndef PRIVATE_UNICODE_ICONV_H__
+#define PRIVATE_UNICODE_ICONV_H__
+
+#include <locale.h>
+#include <iconv.h>
+
+#include "ntlmclient.h"
+
+struct ntlm_unicode_ctx {
+	iconv_t utf8_to_16;
+	iconv_t utf16_to_8;
+};
+
+#endif /* PRIVATE_UNICODE_ICONV_H__ */
diff --git a/script/valgrind.supp b/script/valgrind.supp
index d938aa9c9..8c4549f62 100644
--- a/script/valgrind.supp
+++ b/script/valgrind.supp
@@ -42,6 +42,38 @@
 }
 
 {
+	ignore-openssl-init-leak
+	Memcheck:Leak
+	...
+	fun:git_openssl_stream_global_init
+	...
+}
+
+{
+	ignore-openssl-legacy-init-leak
+	Memcheck:Leak
+	...
+	fun:OPENSSL_init_ssl__legacy
+	...
+}
+
+{
+	ignore-openssl-malloc-leak
+	Memcheck:Leak
+	...
+	fun:git_openssl_malloc
+	...
+}
+
+{
+	ignore-openssl-realloc-leak
+	Memcheck:Leak
+	...
+	fun:git_openssl_realloc
+	...
+}
+
+{
 	ignore-glibc-getaddrinfo-cache
 	Memcheck:Leak
 	...
@@ -65,6 +97,22 @@
 }
 
 {
+	ignore-libssh2-session-create
+	Memcheck:Leak
+	...
+	fun:_git_ssh_session_create
+	...
+}
+
+{
+	ignore-libssh2-setup-conn
+	Memcheck:Leak
+	...
+	fun:_git_ssh_setup_conn
+	...
+}
+
+{
 	ignore-libssh2-gcrypt-control-leak
 	Memcheck:Leak
 	...
@@ -178,3 +226,19 @@
 	obj:*libcrypto.so*
 	...
 }
+
+{
+	ignore-dlopen-leak
+	Memcheck:Leak
+	...
+	fun:dlopen
+	...
+}
+
+{
+	ignore-dlopen-leak
+	Memcheck:Leak
+	...
+	fun:_dlerror_run
+	...
+}
diff --git a/src/features.h.in b/src/features.h.in
index ab523f90b..41f2734ac 100644
--- a/src/features.h.in
+++ b/src/features.h.in
@@ -34,6 +34,7 @@
 #cmakedefine GIT_WINHTTP 1
 #cmakedefine GIT_HTTPS 1
 #cmakedefine GIT_OPENSSL 1
+#cmakedefine GIT_OPENSSL_DYNAMIC 1
 #cmakedefine GIT_SECURE_TRANSPORT 1
 #cmakedefine GIT_MBEDTLS 1
 
diff --git a/src/libgit2.c b/src/libgit2.c
index 089c83590..aee9cf2cd 100644
--- a/src/libgit2.c
+++ b/src/libgit2.c
@@ -36,14 +36,6 @@
 # include "win32/w32_leakcheck.h"
 #endif
 
-#ifdef GIT_OPENSSL
-# include <openssl/err.h>
-#endif
-
-#ifdef GIT_MBEDTLS
-# include <mbedtls/error.h>
-#endif
-
 /* Declarations for tuneable settings */
 extern size_t git_mwindow__window_size;
 extern size_t git_mwindow__mapped_limit;
diff --git a/src/netops.h b/src/netops.h
index 771c87b64..7140b39bc 100644
--- a/src/netops.h
+++ b/src/netops.h
@@ -14,7 +14,7 @@
 #include "net.h"
 
 #ifdef GIT_OPENSSL
-# include <openssl/ssl.h>
+# include "streams/openssl.h"
 #endif
 
 typedef struct gitno_ssl {
diff --git a/src/streams/openssl.c b/src/streams/openssl.c
index 01ce9ce2a..89c96780c 100644
--- a/src/streams/openssl.c
+++ b/src/streams/openssl.c
@@ -6,11 +6,14 @@
  */
 
 #include "streams/openssl.h"
+#include "streams/openssl_legacy.h"
+#include "streams/openssl_dynamic.h"
 
 #ifdef GIT_OPENSSL
 
 #include <ctype.h>
 
+#include "common.h"
 #include "runtime.h"
 #include "settings.h"
 #include "posix.h"
@@ -26,156 +29,17 @@
 # include <netinet/in.h>
 #endif
 
-#include <openssl/ssl.h>
-#include <openssl/err.h>
-#include <openssl/x509v3.h>
-#include <openssl/bio.h>
+#ifndef GIT_OPENSSL_DYNAMIC
+# include <openssl/ssl.h>
+# include <openssl/err.h>
+# include <openssl/x509v3.h>
+# include <openssl/bio.h>
+#endif
 
 SSL_CTX *git__ssl_ctx;
 
 #define GIT_SSL_DEFAULT_CIPHERS "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-DSS-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA:DHE-DSS-AES128-SHA256:DHE-DSS-AES256-SHA256:DHE-DSS-AES128-SHA:DHE-DSS-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA"
 
-#if (defined(OPENSSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER < 0x10100000L) || \
-     (defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x20700000L)
-# define OPENSSL_LEGACY_API
-#endif
-
-/*
- * OpenSSL 1.1 made BIO opaque so we have to use functions to interact with it
- * which do not exist in previous versions. We define these inline functions so
- * we can program against the interface instead of littering the implementation
- * with ifdefs. We do the same for OPENSSL_init_ssl.
- */
-#if defined(OPENSSL_LEGACY_API)
-static int OPENSSL_init_ssl(int opts, void *settings)
-{
-	GIT_UNUSED(opts);
-	GIT_UNUSED(settings);
-	SSL_load_error_strings();
-	OpenSSL_add_ssl_algorithms();
-	return 0;
-}
-
-static BIO_METHOD* BIO_meth_new(int type, const char *name)
-{
-	BIO_METHOD *meth = git__calloc(1, sizeof(BIO_METHOD));
-	if (!meth) {
-		return NULL;
-	}
-
-	meth->type = type;
-	meth->name = name;
-
-	return meth;
-}
-
-static void BIO_meth_free(BIO_METHOD *biom)
-{
-	git__free(biom);
-}
-
-static int BIO_meth_set_write(BIO_METHOD *biom, int (*write) (BIO *, const char *, int))
-{
-	biom->bwrite = write;
-	return 1;
-}
-
-static int BIO_meth_set_read(BIO_METHOD *biom, int (*read) (BIO *, char *, int))
-{
-	biom->bread = read;
-	return 1;
-}
-
-static int BIO_meth_set_puts(BIO_METHOD *biom, int (*puts) (BIO *, const char *))
-{
-	biom->bputs = puts;
-	return 1;
-}
-
-static int BIO_meth_set_gets(BIO_METHOD *biom, int (*gets) (BIO *, char *, int))
-
-{
-	biom->bgets = gets;
-	return 1;
-}
-
-static int BIO_meth_set_ctrl(BIO_METHOD *biom, long (*ctrl) (BIO *, int, long, void *))
-{
-	biom->ctrl = ctrl;
-	return 1;
-}
-
-static int BIO_meth_set_create(BIO_METHOD *biom, int (*create) (BIO *))
-{
-	biom->create = create;
-	return 1;
-}
-
-static int BIO_meth_set_destroy(BIO_METHOD *biom, int (*destroy) (BIO *))
-{
-	biom->destroy = destroy;
-	return 1;
-}
-
-static int BIO_get_new_index(void)
-{
-	/* This exists as of 1.1 so before we'd just have 0 */
-	return 0;
-}
-
-static void BIO_set_init(BIO *b, int init)
-{
-	b->init = init;
-}
-
-static void BIO_set_data(BIO *a, void *ptr)
-{
-	a->ptr = ptr;
-}
-
-static void *BIO_get_data(BIO *a)
-{
-	return a->ptr;
-}
-
-static const unsigned char *ASN1_STRING_get0_data(const ASN1_STRING *x)
-{
-	return ASN1_STRING_data((ASN1_STRING *)x);
-}
-
-# if defined(GIT_THREADS)
-static git_mutex *openssl_locks;
-
-static void openssl_locking_function(
-	int mode, int n, const char *file, int line)
-{
-	int lock;
-
-	GIT_UNUSED(file);
-	GIT_UNUSED(line);
-
-	lock = mode & CRYPTO_LOCK;
-
-	if (lock) {
-		(void)git_mutex_lock(&openssl_locks[n]);
-	} else {
-		git_mutex_unlock(&openssl_locks[n]);
-	}
-}
-
-static void shutdown_ssl_locking(void)
-{
-	int num_locks, i;
-
-	num_locks = CRYPTO_num_locks();
-	CRYPTO_set_locking_callback(NULL);
-
-	for (i = 0; i < num_locks; ++i)
-		git_mutex_free(&openssl_locks[i]);
-	git__free(openssl_locks);
-}
-# endif /* GIT_THREADS */
-#endif /* OPENSSL_LEGACY_API */
 
 static BIO_METHOD *git_stream_bio_method;
 static int init_bio_method(void);
@@ -198,46 +62,47 @@ static void shutdown_ssl(void)
 }
 
 #ifdef VALGRIND
-#ifdef OPENSSL_LEGACY_API
-static void *git_openssl_malloc(size_t bytes)
-{
-	return git__calloc(1, bytes);
-}
+# if !defined(GIT_OPENSSL_LEGACY) && !defined(GIT_OPENSSL_DYNAMIC)
 
-static void *git_openssl_realloc(void *mem, size_t size)
-{
-	return git__realloc(mem, size);
-}
-
-static void git_openssl_free(void *mem)
-{
-	return git__free(mem);
-}
-#else
 static void *git_openssl_malloc(size_t bytes, const char *file, int line)
 {
 	GIT_UNUSED(file);
 	GIT_UNUSED(line);
 	return git__calloc(1, bytes);
 }
-
+ 
 static void *git_openssl_realloc(void *mem, size_t size, const char *file, int line)
 {
 	GIT_UNUSED(file);
 	GIT_UNUSED(line);
 	return git__realloc(mem, size);
 }
-
+ 
 static void git_openssl_free(void *mem, const char *file, int line)
 {
 	GIT_UNUSED(file);
 	GIT_UNUSED(line);
-	return git__free(mem);
+	git__free(mem);
+}
+# else /* !GIT_OPENSSL_LEGACY && !GIT_OPENSSL_DYNAMIC */
+static void *git_openssl_malloc(size_t bytes)
+{
+	return git__calloc(1, bytes);
 }
-#endif
-#endif
 
-int git_openssl_stream_global_init(void)
+static void *git_openssl_realloc(void *mem, size_t size)
+{
+	return git__realloc(mem, size);
+}
+
+static void git_openssl_free(void *mem)
+{
+	git__free(mem);
+}
+# endif /* !GIT_OPENSSL_LEGACY && !GIT_OPENSSL_DYNAMIC */
+#endif /* VALGRIND */
+
+static int openssl_init(void)
 {
 	long ssl_opts = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3;
 	const char *ciphers = git_libgit2__ssl_ciphers();
@@ -301,42 +166,60 @@ error:
 	return -1;
 }
 
-#if defined(GIT_THREADS) && defined(OPENSSL_LEGACY_API)
-static void threadid_cb(CRYPTO_THREADID *threadid)
+/*
+ * When we use dynamic loading, we defer OpenSSL initialization until
+ * it's first used.  `openssl_ensure_initialized` will do the work
+ * under a mutex.
+ */
+git_mutex openssl_mutex;
+bool openssl_initialized;
+
+int git_openssl_stream_global_init(void)
 {
-	GIT_UNUSED(threadid);
-	CRYPTO_THREADID_set_numeric(threadid, git_thread_currentid());
-}
+#ifndef GIT_OPENSSL_DYNAMIC
+	return openssl_init();
+#else
+	if (git_mutex_init(&openssl_mutex) != 0)
+		return -1;
+
+	return 0;
 #endif
+}
 
-int git_openssl_set_locking(void)
+static int openssl_ensure_initialized(void)
 {
-#if defined(GIT_THREADS) && defined(OPENSSL_LEGACY_API)
-	int num_locks, i;
+#ifdef GIT_OPENSSL_DYNAMIC
+	int error = 0;
 
-	CRYPTO_THREADID_set_callback(threadid_cb);
+	if (git_mutex_lock(&openssl_mutex) != 0)
+		return -1;
 
-	num_locks = CRYPTO_num_locks();
-	openssl_locks = git__calloc(num_locks, sizeof(git_mutex));
-	GIT_ERROR_CHECK_ALLOC(openssl_locks);
+	if (!openssl_initialized) {
+		if ((error = git_openssl_stream_dynamic_init()) == 0)
+			error = openssl_init();
 
-	for (i = 0; i < num_locks; i++) {
-		if (git_mutex_init(&openssl_locks[i]) != 0) {
-			git_error_set(GIT_ERROR_SSL, "failed to initialize openssl locks");
-			return -1;
-		}
+		openssl_initialized = true;
 	}
 
-	CRYPTO_set_locking_callback(openssl_locking_function);
-	return git_runtime_shutdown_register(shutdown_ssl_locking);
+	error |= git_mutex_unlock(&openssl_mutex);
+	return error;
 
-#elif !defined(OPENSSL_LEGACY_API)
-	return 0;
 #else
+	return 0;
+#endif
+}
+
+#if !defined(GIT_OPENSSL_LEGACY) && !defined(GIT_OPENSSL_DYNAMIC)
+int git_openssl_set_locking(void)
+{
+# ifdef GIT_THREADS
+	return 0;
+# else
 	git_error_set(GIT_ERROR_THREAD, "libgit2 was not built with threads");
 	return -1;
-#endif
+# endif
 }
+#endif
 
 
 static int bio_create(BIO *b)
@@ -799,6 +682,9 @@ static int openssl_stream_wrap(
 
 int git_openssl_stream_wrap(git_stream **out, git_stream *in, const char *host)
 {
+	if (openssl_ensure_initialized() < 0)
+		return -1;
+
 	return openssl_stream_wrap(out, in, host, 0);
 }
 
@@ -811,6 +697,9 @@ int git_openssl_stream_new(git_stream **out, const char *host, const char *port)
 	GIT_ASSERT_ARG(host);
 	GIT_ASSERT_ARG(port);
 
+	if (openssl_ensure_initialized() < 0)
+		return -1;
+
 	if ((error = git_socket_stream_new(&stream, host, port)) < 0)
 		return error;
 
@@ -824,6 +713,9 @@ int git_openssl_stream_new(git_stream **out, const char *host, const char *port)
 
 int git_openssl__set_cert_location(const char *file, const char *path)
 {
+	if (openssl_ensure_initialized() < 0)
+		return -1;
+
 	if (SSL_CTX_load_verify_locations(git__ssl_ctx, file, path) == 0) {
 		char errmsg[256];
 
diff --git a/src/streams/openssl.h b/src/streams/openssl.h
index 826d1efbc..89fb60a82 100644
--- a/src/streams/openssl.h
+++ b/src/streams/openssl.h
@@ -8,14 +8,22 @@
 #define INCLUDE_streams_openssl_h__
 
 #include "common.h"
+#include "streams/openssl_legacy.h"
+#include "streams/openssl_dynamic.h"
 
 #include "git2/sys/stream.h"
 
 extern int git_openssl_stream_global_init(void);
 
+#if defined(GIT_OPENSSL) && !defined(GIT_OPENSSL_DYNAMIC)
+# include <openssl/ssl.h>
+# include <openssl/err.h>
+# include <openssl/x509v3.h>
+# include <openssl/bio.h>
+# endif
+
 #ifdef GIT_OPENSSL
 extern int git_openssl__set_cert_location(const char *file, const char *path);
-
 extern int git_openssl_stream_new(git_stream **out, const char *host, const char *port);
 extern int git_openssl_stream_wrap(git_stream **out, git_stream *in, const char *host);
 #endif
diff --git a/src/streams/openssl_dynamic.c b/src/streams/openssl_dynamic.c
new file mode 100644
index 000000000..da16b6ed7
--- /dev/null
+++ b/src/streams/openssl_dynamic.c
@@ -0,0 +1,309 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "streams/openssl.h"
+#include "streams/openssl_dynamic.h"
+
+#if defined(GIT_OPENSSL) && defined(GIT_OPENSSL_DYNAMIC)
+
+#include "runtime.h"
+
+#include <dlfcn.h>
+
+unsigned char *(*ASN1_STRING_data)(ASN1_STRING *x);
+const unsigned char *(*ASN1_STRING_get0_data)(const ASN1_STRING *x);
+int (*ASN1_STRING_length)(const ASN1_STRING *x);
+int (*ASN1_STRING_to_UTF8)(unsigned char **out, const ASN1_STRING *in);
+int (*ASN1_STRING_type)(const ASN1_STRING *x);
+
+void *(*BIO_get_data)(BIO *a);
+int (*BIO_get_new_index)(void);
+int (*OPENSSL_init_ssl)(uint64_t opts, const void *settings);
+void (*BIO_meth_free)(BIO_METHOD *biom);
+int (*BIO_meth_set_create)(BIO_METHOD *biom, int (*create) (BIO *));
+int (*BIO_meth_set_ctrl)(BIO_METHOD *biom, long (*ctrl) (BIO *, int, long, void *));
+int (*BIO_meth_set_destroy)(BIO_METHOD *biom, int (*destroy) (BIO *));
+int (*BIO_meth_set_gets)(BIO_METHOD *biom, int (*gets) (BIO *, char *, int));
+int (*BIO_meth_set_puts)(BIO_METHOD *biom, int (*puts) (BIO *, const char *));
+int (*BIO_meth_set_read)(BIO_METHOD *biom, int (*read) (BIO *, char *, int));
+int (*BIO_meth_set_write)(BIO_METHOD *biom, int (*write) (BIO *, const char *, int));
+BIO_METHOD *(*BIO_meth_new)(int type, const char *name);
+BIO *(*BIO_new)(const BIO_METHOD *type);
+void (*BIO_set_data)(BIO *a, void *ptr);
+void (*BIO_set_init)(BIO *a, int init);
+
+void (*CRYPTO_free)(void *ptr, const char *file, int line);
+void *(*CRYPTO_malloc)(size_t num, const char *file, int line);
+int (*CRYPTO_num_locks)(void);
+void (*CRYPTO_set_locking_callback)(void (*func)(int mode, int type, const char *file, int line));
+int (*CRYPTO_set_mem_functions)(void *(*m)(size_t bytes), void *(*r)(void *mem, size_t size), void (*f)(void *mem));
+int (*CRYPTO_THREADID_set_callback)(void (*func)(CRYPTO_THREADID *id));
+void (*CRYPTO_THREADID_set_numeric)(CRYPTO_THREADID *id, unsigned long val);
+
+char *(*ERR_error_string)(unsigned long e, char *buf);
+void (*ERR_error_string_n)(unsigned long e, char *buf, size_t len);
+unsigned long (*ERR_get_error)(void);
+
+int (*SSL_connect)(SSL *ssl);
+long (*SSL_ctrl)(SSL *ssl, int cmd, long arg, void *parg);
+void (*SSL_free)(SSL *ssl);
+int (*SSL_get_error)(SSL *ssl, int ret);
+X509 *(*SSL_get_peer_certificate)(const SSL *ssl);
+long (*SSL_get_verify_result)(const SSL *ssl);
+int (*SSL_library_init)(void);
+void (*SSL_load_error_strings)(void);
+SSL *(*SSL_new)(SSL_CTX *ctx);
+int (*SSL_read)(SSL *ssl, const void *buf, int num);
+void (*SSL_set_bio)(SSL *ssl, BIO *rbio, BIO *wbio);
+int (*SSL_shutdown)(SSL *ssl);
+int (*SSL_write)(SSL *ssl, const void *buf, int num);
+
+long (*SSL_CTX_ctrl)(SSL_CTX *ctx, int cmd, long larg, void *parg);
+void (*SSL_CTX_free)(SSL_CTX *ctx);
+SSL_CTX *(*SSL_CTX_new)(const SSL_METHOD *method);
+int (*SSL_CTX_set_cipher_list)(SSL_CTX *ctx, const char *str);
+int (*SSL_CTX_set_default_verify_paths)(SSL_CTX *ctx);
+long (*SSL_CTX_set_options)(SSL_CTX *ctx, long options);
+void (*SSL_CTX_set_verify)(SSL_CTX *ctx, int mode, int (*verify_callback)(int, X509_STORE_CTX *));
+int (*SSL_CTX_load_verify_locations)(SSL_CTX *ctx, const char *CAfile, const char *CApath);
+
+const SSL_METHOD *(*SSLv23_method)(void);
+const SSL_METHOD *(*TLS_method)(void);
+
+ASN1_STRING *(*X509_NAME_ENTRY_get_data)(const X509_NAME_ENTRY *ne);
+X509_NAME_ENTRY *(*X509_NAME_get_entry)(X509_NAME *name, int loc);
+int (*X509_NAME_get_index_by_NID)(X509_NAME *name, int nid, int lastpos);
+void (*X509_free)(X509 *a);
+void *(*X509_get_ext_d2i)(const X509 *x, int nid, int *crit, int *idx);
+X509_NAME *(*X509_get_subject_name)(const X509 *x);
+
+int (*i2d_X509)(X509 *a, unsigned char **ppout);
+
+int (*OPENSSL_sk_num)(const void *sk);
+void *(*OPENSSL_sk_value)(const void *sk, int i);
+void (*OPENSSL_sk_free)(void *sk);
+
+int (*sk_num)(const void *sk);
+void *(*sk_value)(const void *sk, int i);
+void (*sk_free)(void *sk);
+
+void *openssl_handle;
+
+GIT_INLINE(void *) openssl_sym(int *err, const char *name, bool required)
+{
+	void *symbol;
+
+	/* if we've seen an err, noop to retain it */
+	if (*err)
+		return NULL;
+
+
+	if ((symbol = dlsym(openssl_handle, name)) == NULL && required) {
+		const char *msg = dlerror();
+		git_error_set(GIT_ERROR_SSL, "could not load ssl function '%s': %s", name, msg ? msg : "unknown error");
+		*err = -1;
+	}
+
+	return symbol;
+}
+
+static void dynamic_shutdown(void)
+{
+	dlclose(openssl_handle);
+	openssl_handle = NULL;
+}
+
+int git_openssl_stream_dynamic_init(void)
+{
+	int err = 0;
+
+	if ((openssl_handle = dlopen("libssl.so.1.1", RTLD_NOW)) == NULL &&
+	    (openssl_handle = dlopen("libssl.1.1.dylib", RTLD_NOW)) == NULL &&
+	    (openssl_handle = dlopen("libssl.so.1.0.0", RTLD_NOW)) == NULL &&
+	    (openssl_handle = dlopen("libssl.1.0.0.dylib", RTLD_NOW)) == NULL &&
+	    (openssl_handle = dlopen("libssl.so.10", RTLD_NOW)) == NULL) {
+		git_error_set(GIT_ERROR_SSL, "could not load ssl libraries");
+		return -1;
+	}
+
+	ASN1_STRING_data = (unsigned char *(*)(ASN1_STRING *x))openssl_sym(&err, "ASN1_STRING_data", false);
+	ASN1_STRING_get0_data = (const unsigned char *(*)(const ASN1_STRING *x))openssl_sym(&err, "ASN1_STRING_get0_data", false);
+	ASN1_STRING_length = (int (*)(const ASN1_STRING *))openssl_sym(&err, "ASN1_STRING_length", true);
+	ASN1_STRING_to_UTF8 = (int (*)(unsigned char **, const ASN1_STRING *))openssl_sym(&err, "ASN1_STRING_to_UTF8", true);
+	ASN1_STRING_type = (int (*)(const ASN1_STRING *))openssl_sym(&err, "ASN1_STRING_type", true);
+
+	BIO_get_data = (void *(*)(BIO *))openssl_sym(&err, "BIO_get_data", false);
+	BIO_get_new_index = (int (*)(void))openssl_sym(&err, "BIO_get_new_index", false);
+	BIO_meth_free = (void (*)(BIO_METHOD *))openssl_sym(&err, "BIO_meth_free", false);
+	BIO_meth_new = (BIO_METHOD *(*)(int, const char *))openssl_sym(&err, "BIO_meth_new", false);
+	BIO_meth_set_create = (int (*)(BIO_METHOD *, int (*)(BIO *)))openssl_sym(&err, "BIO_meth_set_create", false);
+	BIO_meth_set_ctrl = (int (*)(BIO_METHOD *, long (*)(BIO *, int, long, void *)))openssl_sym(&err, "BIO_meth_set_ctrl", false);
+	BIO_meth_set_destroy = (int (*)(BIO_METHOD *, int (*)(BIO *)))openssl_sym(&err, "BIO_meth_set_destroy", false);
+	BIO_meth_set_gets = (int (*)(BIO_METHOD *, int (*)(BIO *, char *, int)))openssl_sym(&err, "BIO_meth_set_gets", false);
+	BIO_meth_set_puts = (int (*)(BIO_METHOD *, int (*)(BIO *, const char *)))openssl_sym(&err, "BIO_meth_set_puts", false);
+	BIO_meth_set_read = (int (*)(BIO_METHOD *, int (*)(BIO *, char *, int)))openssl_sym(&err, "BIO_meth_set_read", false);
+	BIO_meth_set_write = (int (*)(BIO_METHOD *, int (*)(BIO *, const char *, int)))openssl_sym(&err, "BIO_meth_set_write", false);
+	BIO_new = (BIO *(*)(const BIO_METHOD *))openssl_sym(&err, "BIO_new", true);
+	BIO_set_data = (void (*)(BIO *a, void *))openssl_sym(&err, "BIO_set_data", false);
+	BIO_set_init = (void (*)(BIO *a, int))openssl_sym(&err, "BIO_set_init", false);
+
+	CRYPTO_free = (void (*)(void *, const char *, int))openssl_sym(&err, "CRYPTO_free", true);
+	CRYPTO_malloc = (void *(*)(size_t, const char *, int))openssl_sym(&err, "CRYPTO_malloc", true);
+	CRYPTO_num_locks = (int (*)(void))openssl_sym(&err, "CRYPTO_num_locks", false);
+	CRYPTO_set_locking_callback = (void (*)(void (*)(int, int, const char *, int)))openssl_sym(&err, "CRYPTO_set_locking_callback", false);
+	CRYPTO_set_mem_functions = (int (*)(void *(*)(size_t), void *(*)(void *, size_t), void (*f)(void *)))openssl_sym(&err, "CRYPTO_set_mem_functions", true);
+
+	CRYPTO_THREADID_set_callback = (int (*)(void (*)(CRYPTO_THREADID *)))openssl_sym(&err, "CRYPTO_THREADID_set_callback", false);
+	CRYPTO_THREADID_set_numeric = (void (*)(CRYPTO_THREADID *, unsigned long))openssl_sym(&err, "CRYPTO_THREADID_set_numeric", false);
+
+	ERR_error_string = (char *(*)(unsigned long, char *))openssl_sym(&err, "ERR_error_string", true);
+	ERR_error_string_n = (void (*)(unsigned long, char *, size_t))openssl_sym(&err, "ERR_error_string_n", true);
+	ERR_get_error = (unsigned long (*)(void))openssl_sym(&err, "ERR_get_error", true);
+
+	OPENSSL_init_ssl = (int (*)(uint64_t opts, const void *settings))openssl_sym(&err, "OPENSSL_init_ssl", false);
+	OPENSSL_sk_num = (int (*)(const void *))openssl_sym(&err, "OPENSSL_sk_num", false);
+	OPENSSL_sk_value = (void *(*)(const void *sk, int i))openssl_sym(&err, "OPENSSL_sk_value", false);
+	OPENSSL_sk_free = (void (*)(void *))openssl_sym(&err, "OPENSSL_sk_free", false);
+
+	sk_num = (int (*)(const void *))openssl_sym(&err, "sk_num", false);
+	sk_value = (void *(*)(const void *sk, int i))openssl_sym(&err, "sk_value", false);
+	sk_free = (void (*)(void *))openssl_sym(&err, "sk_free", false);
+
+	SSL_connect = (int (*)(SSL *))openssl_sym(&err, "SSL_connect", true);
+	SSL_ctrl = (long (*)(SSL *, int, long, void *))openssl_sym(&err, "SSL_ctrl", true);
+	SSL_get_peer_certificate = (X509 *(*)(const SSL *))openssl_sym(&err, "SSL_get_peer_certificate", true);
+	SSL_library_init = (int (*)(void))openssl_sym(&err, "SSL_library_init", false);
+	SSL_free = (void (*)(SSL *))openssl_sym(&err, "SSL_free", true);
+	SSL_get_error = (int (*)(SSL *, int))openssl_sym(&err, "SSL_get_error", true);
+	SSL_get_verify_result = (long (*)(const SSL *ssl))openssl_sym(&err, "SSL_get_verify_result", true);
+	SSL_load_error_strings = (void (*)(void))openssl_sym(&err, "SSL_load_error_strings", false);
+	SSL_new = (SSL *(*)(SSL_CTX *))openssl_sym(&err, "SSL_new", true);
+	SSL_read = (int (*)(SSL *, const void *, int))openssl_sym(&err, "SSL_read", true);
+	SSL_set_bio = (void (*)(SSL *, BIO *, BIO *))openssl_sym(&err, "SSL_set_bio", true);
+	SSL_shutdown = (int (*)(SSL *ssl))openssl_sym(&err, "SSL_shutdown", true);
+	SSL_write = (int (*)(SSL *, const void *, int))openssl_sym(&err, "SSL_write", true);
+
+	SSL_CTX_ctrl = (long (*)(SSL_CTX *, int, long, void *))openssl_sym(&err, "SSL_CTX_ctrl", true);
+	SSL_CTX_free = (void (*)(SSL_CTX *))openssl_sym(&err, "SSL_CTX_free", true);
+	SSL_CTX_new = (SSL_CTX *(*)(const SSL_METHOD *))openssl_sym(&err, "SSL_CTX_new", true);
+	SSL_CTX_set_cipher_list = (int (*)(SSL_CTX *, const char *))openssl_sym(&err, "SSL_CTX_set_cipher_list", true);
+	SSL_CTX_set_default_verify_paths = (int (*)(SSL_CTX *ctx))openssl_sym(&err, "SSL_CTX_set_default_verify_paths", true);
+	SSL_CTX_set_options = (long (*)(SSL_CTX *, long))openssl_sym(&err, "SSL_CTX_set_options", false);
+	SSL_CTX_set_verify = (void (*)(SSL_CTX *, int, int (*)(int, X509_STORE_CTX *)))openssl_sym(&err, "SSL_CTX_set_verify", true);
+	SSL_CTX_load_verify_locations = (int (*)(SSL_CTX *, const char *, const char *))openssl_sym(&err, "SSL_CTX_load_verify_locations", true);
+
+	SSLv23_method = (const SSL_METHOD *(*)(void))openssl_sym(&err, "SSLv23_method", false);
+	TLS_method = (const SSL_METHOD *(*)(void))openssl_sym(&err, "TLS_method", false);
+
+	X509_NAME_ENTRY_get_data = (ASN1_STRING *(*)(const X509_NAME_ENTRY *))openssl_sym(&err, "X509_NAME_ENTRY_get_data", true);
+	X509_NAME_get_entry = (X509_NAME_ENTRY *(*)(X509_NAME *, int))openssl_sym(&err, "X509_NAME_get_entry", true);
+	X509_NAME_get_index_by_NID = (int (*)(X509_NAME *, int, int))openssl_sym(&err, "X509_NAME_get_index_by_NID", true);
+	X509_free = (void (*)(X509 *))openssl_sym(&err, "X509_free", true);
+	X509_get_ext_d2i = (void *(*)(const X509 *x, int nid, int *crit, int *idx))openssl_sym(&err, "X509_get_ext_d2i", true);
+	X509_get_subject_name = (X509_NAME *(*)(const X509 *))openssl_sym(&err, "X509_get_subject_name", true);
+
+	i2d_X509 = (int (*)(X509 *a, unsigned char **ppout))openssl_sym(&err, "i2d_X509", true);
+
+	if (err)
+		goto on_error;
+
+	/* Add legacy functionality */
+	if (!OPENSSL_init_ssl) {
+		OPENSSL_init_ssl = OPENSSL_init_ssl__legacy;
+
+		if (!SSL_library_init ||
+		    !SSL_load_error_strings ||
+		    !CRYPTO_num_locks ||
+		    !CRYPTO_set_locking_callback ||
+		    !CRYPTO_THREADID_set_callback ||
+		    !CRYPTO_THREADID_set_numeric) {
+			git_error_set(GIT_ERROR_SSL, "could not load legacy openssl initialization functions");
+			goto on_error;
+		}
+	}
+
+	if (!SSL_CTX_set_options)
+		SSL_CTX_set_options = SSL_CTX_set_options__legacy;
+
+	if (TLS_method)
+		SSLv23_method = TLS_method;
+
+	if (!BIO_meth_new) {
+		BIO_meth_new = BIO_meth_new__legacy;
+		BIO_meth_new = BIO_meth_new__legacy;
+		BIO_meth_free = BIO_meth_free__legacy;
+		BIO_meth_set_write = BIO_meth_set_write__legacy;
+		BIO_meth_set_read = BIO_meth_set_read__legacy;
+		BIO_meth_set_puts = BIO_meth_set_puts__legacy;
+		BIO_meth_set_gets = BIO_meth_set_gets__legacy;
+		BIO_meth_set_ctrl = BIO_meth_set_ctrl__legacy;
+		BIO_meth_set_create = BIO_meth_set_create__legacy;
+		BIO_meth_set_destroy = BIO_meth_set_destroy__legacy;
+		BIO_get_new_index = BIO_get_new_index__legacy;
+		BIO_set_data = BIO_set_data__legacy;
+		BIO_set_init = BIO_set_init__legacy;
+		BIO_get_data = BIO_get_data__legacy;
+	}
+
+	if (!ASN1_STRING_get0_data) {
+		if (!ASN1_STRING_data) {
+			git_error_set(GIT_ERROR_SSL, "could not load legacy openssl string function");
+			goto on_error;
+		}
+
+		ASN1_STRING_get0_data = ASN1_STRING_get0_data__legacy;
+	}
+
+	if ((!OPENSSL_sk_num && !sk_num) ||
+	    (!OPENSSL_sk_value && !sk_value) ||
+	    (!OPENSSL_sk_free && !sk_free)) {
+		git_error_set(GIT_ERROR_SSL, "could not load legacy openssl stack functions");
+		goto on_error;
+	}
+
+	if (git_runtime_shutdown_register(dynamic_shutdown) != 0)
+		goto on_error;
+
+	return 0;
+
+on_error:
+	dlclose(openssl_handle);
+	return -1;
+}
+
+
+int sk_GENERAL_NAME_num(const GENERAL_NAME *sk)
+{
+	if (OPENSSL_sk_num)
+		return OPENSSL_sk_num(sk);
+	else if (sk_num)
+		return sk_num(sk);
+
+	GIT_ASSERT_WITH_RETVAL(false, 0);
+	return 0;
+}
+
+GENERAL_NAME *sk_GENERAL_NAME_value(const GENERAL_NAME *sk, int i)
+{
+	if (OPENSSL_sk_value)
+		return OPENSSL_sk_value(sk, i);
+	else if (sk_value)
+		return sk_value(sk, i);
+
+	GIT_ASSERT_WITH_RETVAL(false, NULL);
+	return NULL;
+}
+
+void GENERAL_NAMES_free(GENERAL_NAME *sk)
+{
+	if (OPENSSL_sk_free)
+		OPENSSL_sk_free(sk);
+	else if (sk_free)
+		sk_free(sk);
+}
+
+#endif /* GIT_OPENSSL && GIT_OPENSSL_DYNAMIC */
diff --git a/src/streams/openssl_dynamic.h b/src/streams/openssl_dynamic.h
new file mode 100644
index 000000000..12d927a61
--- /dev/null
+++ b/src/streams/openssl_dynamic.h
@@ -0,0 +1,348 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ *
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to.  The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ *
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *    "This product includes cryptographic software written by
+ *     Eric Young (eay@cryptsoft.com)"
+ *    The word 'cryptographic' can be left out if the rouines from the library
+ *    being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from
+ *    the apps directory (application code) you must include an acknowledgement:
+ *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed.  i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.]
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2007 The OpenSSL Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
+/* ====================================================================
+ * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
+ * ECC cipher suite support in OpenSSL originally developed by
+ * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
+ */
+/* ====================================================================
+ * Copyright 2005 Nokia. All rights reserved.
+ *
+ * The portions of the attached software ("Contribution") is developed by
+ * Nokia Corporation and is licensed pursuant to the OpenSSL open source
+ * license.
+ *
+ * The Contribution, originally written by Mika Kousa and Pasi Eronen of
+ * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
+ * support (see RFC 4279) to OpenSSL.
+ *
+ * No patent licenses or other rights except those expressly stated in
+ * the OpenSSL open source license shall be deemed granted or received
+ * expressly, by implication, estoppel, or otherwise.
+ *
+ * No assurances are provided by Nokia that the Contribution does not
+ * infringe the patent or other intellectual property rights of any third
+ * party or that the license provides you with all the necessary rights
+ * to make use of the Contribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
+ * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
+ * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
+ * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
+ * OTHERWISE.
+ */
+
+#ifndef INCLUDE_streams_openssl_dynamic_h__
+#define INCLUDE_streams_openssl_dynamic_h__
+
+#ifdef GIT_OPENSSL_DYNAMIC
+
+# define BIO_CTRL_FLUSH               11
+
+# define BIO_TYPE_SOURCE_SINK         0x0400
+
+# define CRYPTO_LOCK                  1
+
+# define GEN_DNS                      2
+# define GEN_IPADD                    7
+
+# define NID_commonName               13
+# define NID_subject_alt_name         85
+
+# define SSL_VERIFY_NONE              0x00
+
+# define SSL_CTRL_OPTIONS             32
+# define SSL_CTRL_MODE                33
+# define SSL_CTRL_SET_TLSEXT_HOSTNAME 55
+
+# define SSL_ERROR_NONE               0
+# define SSL_ERROR_SSL                1
+# define SSL_ERROR_WANT_READ          2
+# define SSL_ERROR_WANT_WRITE         3
+# define SSL_ERROR_WANT_X509_LOOKUP   4
+# define SSL_ERROR_SYSCALL            5
+# define SSL_ERROR_ZERO_RETURN        6
+# define SSL_ERROR_WANT_CONNECT       7
+# define SSL_ERROR_WANT_ACCEPT        8
+
+# define SSL_OP_NO_COMPRESSION        0x00020000L
+# define SSL_OP_NO_SSLv2              0x01000000L
+# define SSL_OP_NO_SSLv3              0x02000000L
+
+# define SSL_MODE_AUTO_RETRY          0x00000004L
+
+# define TLSEXT_NAMETYPE_host_name    0
+
+# define V_ASN1_UTF8STRING            12
+
+# define X509_V_OK 0
+
+/* Most of the OpenSSL types are mercifully opaque, so we can treat them like `void *` */
+typedef struct bio_st BIO;
+typedef struct bio_method_st BIO_METHOD;
+typedef void bio_info_cb;
+typedef void * CRYPTO_EX_DATA;
+typedef void CRYPTO_THREADID;
+typedef void GENERAL_NAMES;
+typedef void SSL;
+typedef void SSL_CTX;
+typedef void SSL_METHOD;
+typedef void X509;
+typedef void X509_NAME;
+typedef void X509_NAME_ENTRY;
+typedef void X509_STORE_CTX;
+
+typedef struct {
+    int length;
+    int type;
+    unsigned char *data;
+    long flags;
+} ASN1_STRING;
+
+typedef struct {
+    int type;
+    union {
+        char *ptr;
+        ASN1_STRING *ia5;
+    } d;
+} GENERAL_NAME;
+
+struct bio_st {
+    BIO_METHOD *method;
+    /* bio, mode, argp, argi, argl, ret */
+    long (*callback) (struct bio_st *, int, const char *, int, long, long);
+    char *cb_arg;               /* first argument for the callback */
+    int init;
+    int shutdown;
+    int flags;                  /* extra storage */
+    int retry_reason;
+    int num;
+    void *ptr;
+    struct bio_st *next_bio;    /* used by filter BIOs */
+    struct bio_st *prev_bio;    /* used by filter BIOs */
+    int references;
+    unsigned long num_read;
+    unsigned long num_write;
+    CRYPTO_EX_DATA ex_data;
+};
+
+struct bio_method_st {
+    int type;
+    const char *name;
+    int (*bwrite) (BIO *, const char *, int);
+    int (*bread) (BIO *, char *, int);
+    int (*bputs) (BIO *, const char *);
+    int (*bgets) (BIO *, char *, int);
+    long (*ctrl) (BIO *, int, long, void *);
+    int (*create) (BIO *);
+    int (*destroy) (BIO *);
+    long (*callback_ctrl) (BIO *, int, bio_info_cb *);
+};
+
+extern unsigned char *(*ASN1_STRING_data)(ASN1_STRING *x);
+extern const unsigned char *(*ASN1_STRING_get0_data)(const ASN1_STRING *x);
+extern int (*ASN1_STRING_length)(const ASN1_STRING *x);
+extern int (*ASN1_STRING_to_UTF8)(unsigned char **out, const ASN1_STRING *in);
+extern int (*ASN1_STRING_type)(const ASN1_STRING *x);
+
+extern void *(*BIO_get_data)(BIO *a);
+extern int (*BIO_get_new_index)(void);
+extern int (*OPENSSL_init_ssl)(uint64_t opts, const void *settings);
+extern void (*BIO_meth_free)(BIO_METHOD *biom);
+extern int (*BIO_meth_set_create)(BIO_METHOD *biom, int (*create) (BIO *));
+extern int (*BIO_meth_set_ctrl)(BIO_METHOD *biom, long (*ctrl) (BIO *, int, long, void *));
+extern int (*BIO_meth_set_destroy)(BIO_METHOD *biom, int (*destroy) (BIO *));
+extern int (*BIO_meth_set_gets)(BIO_METHOD *biom, int (*gets) (BIO *, char *, int));
+extern int (*BIO_meth_set_puts)(BIO_METHOD *biom, int (*puts) (BIO *, const char *));
+extern int (*BIO_meth_set_read)(BIO_METHOD *biom, int (*read) (BIO *, char *, int));
+extern int (*BIO_meth_set_write)(BIO_METHOD *biom, int (*write) (BIO *, const char *, int));
+extern BIO_METHOD *(*BIO_meth_new)(int type, const char *name);
+extern BIO *(*BIO_new)(const BIO_METHOD *type);
+extern void (*BIO_set_data)(BIO *a, void *ptr);
+extern void (*BIO_set_init)(BIO *a, int init);
+
+extern void (*CRYPTO_free)(void *ptr, const char *file, int line);
+extern void *(*CRYPTO_malloc)(size_t num, const char *file, int line);
+extern int (*CRYPTO_num_locks)(void);
+extern void (*CRYPTO_set_locking_callback)(void (*func)(int mode, int type, const char *file, int line));
+extern int (*CRYPTO_set_mem_functions)(void *(*m)(size_t bytes), void *(*r)(void *mem, size_t size), void (*f)(void *mem));
+extern int (*CRYPTO_THREADID_set_callback)(void (*func)(CRYPTO_THREADID *id));
+extern void (*CRYPTO_THREADID_set_numeric)(CRYPTO_THREADID *id, unsigned long val);
+
+extern char *(*ERR_error_string)(unsigned long e, char *buf);
+extern void (*ERR_error_string_n)(unsigned long e, char *buf, size_t len);
+extern unsigned long (*ERR_get_error)(void);
+
+# define OPENSSL_malloc(num) CRYPTO_malloc(num, __FILE__, __LINE__)
+# define OPENSSL_free(addr) CRYPTO_free(addr, __FILE__, __LINE__)
+
+extern int (*SSL_connect)(SSL *ssl);
+extern long (*SSL_ctrl)(SSL *ssl, int cmd, long arg, void *parg);
+extern void (*SSL_free)(SSL *ssl);
+extern int (*SSL_get_error)(SSL *ssl, int ret);
+extern X509 *(*SSL_get_peer_certificate)(const SSL *ssl);
+extern long (*SSL_get_verify_result)(const SSL *ssl);
+extern int (*SSL_library_init)(void);
+extern void (*SSL_load_error_strings)(void);
+extern SSL *(*SSL_new)(SSL_CTX *ctx);
+extern int (*SSL_read)(SSL *ssl, const void *buf, int num);
+extern void (*SSL_set_bio)(SSL *ssl, BIO *rbio, BIO *wbio);
+extern int (*SSL_shutdown)(SSL *ssl);
+extern int (*SSL_write)(SSL *ssl, const void *buf, int num);
+
+# define SSL_set_tlsext_host_name(s, name) SSL_ctrl((s), SSL_CTRL_SET_TLSEXT_HOSTNAME, TLSEXT_NAMETYPE_host_name, (char *)(name));
+
+extern long (*SSL_CTX_ctrl)(SSL_CTX *ctx, int cmd, long larg, void *parg);
+extern void (*SSL_CTX_free)(SSL_CTX *ctx);
+extern SSL_CTX *(*SSL_CTX_new)(const SSL_METHOD *method);
+extern int (*SSL_CTX_set_cipher_list)(SSL_CTX *ctx, const char *str);
+extern int (*SSL_CTX_set_default_verify_paths)(SSL_CTX *ctx);
+extern long (*SSL_CTX_set_options)(SSL_CTX *ctx, long options);
+extern void (*SSL_CTX_set_verify)(SSL_CTX *ctx, int mode, int (*verify_callback)(int, X509_STORE_CTX *));
+extern int (*SSL_CTX_load_verify_locations)(SSL_CTX *ctx, const char *CAfile, const char *CApath);
+
+# define SSL_CTX_set_mode(ctx, mode) SSL_CTX_ctrl((ctx), SSL_CTRL_MODE, (mode), NULL);
+
+extern const SSL_METHOD *(*SSLv23_method)(void);
+extern const SSL_METHOD *(*TLS_method)(void);
+
+extern ASN1_STRING *(*X509_NAME_ENTRY_get_data)(const X509_NAME_ENTRY *ne);
+extern X509_NAME_ENTRY *(*X509_NAME_get_entry)(X509_NAME *name, int loc);
+extern int (*X509_NAME_get_index_by_NID)(X509_NAME *name, int nid, int lastpos);
+extern void (*X509_free)(X509 *a);
+extern void *(*X509_get_ext_d2i)(const X509 *x, int nid, int *crit, int *idx);
+extern X509_NAME *(*X509_get_subject_name)(const X509 *x);
+
+extern int (*i2d_X509)(X509 *a, unsigned char **ppout);
+
+extern int (*OPENSSL_sk_num)(const void *sk);
+extern void *(*OPENSSL_sk_value)(const void *sk, int i);
+extern void (*OPENSSL_sk_free)(void *sk);
+
+extern int (*sk_num)(const void *sk);
+extern void *(*sk_value)(const void *sk, int i);
+extern void (*sk_free)(void *sk);
+
+extern int sk_GENERAL_NAME_num(const GENERAL_NAME *sk);
+extern GENERAL_NAME *sk_GENERAL_NAME_value(const GENERAL_NAME *sk, int i);
+extern void GENERAL_NAMES_free(GENERAL_NAME *sk);
+
+extern int git_openssl_stream_dynamic_init(void);
+
+#endif /* GIT_OPENSSL_DYNAMIC */
+
+#endif
diff --git a/src/streams/openssl_legacy.c b/src/streams/openssl_legacy.c
new file mode 100644
index 000000000..1c1ff60c0
--- /dev/null
+++ b/src/streams/openssl_legacy.c
@@ -0,0 +1,203 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "streams/openssl.h"
+#include "streams/openssl_legacy.h"
+
+#include "runtime.h"
+#include "git2/sys/openssl.h"
+
+#if defined(GIT_OPENSSL) && !defined(GIT_OPENSSL_DYNAMIC)
+# include <openssl/ssl.h>
+# include <openssl/err.h>
+# include <openssl/x509v3.h>
+# include <openssl/bio.h>
+#endif
+
+#if defined(GIT_OPENSSL_LEGACY) || defined(GIT_OPENSSL_DYNAMIC)
+
+/*
+ * OpenSSL 1.1 made BIO opaque so we have to use functions to interact with it
+ * which do not exist in previous versions. We define these inline functions so
+ * we can program against the interface instead of littering the implementation
+ * with ifdefs. We do the same for OPENSSL_init_ssl.
+ */
+
+int OPENSSL_init_ssl__legacy(uint64_t opts, const void *settings)
+{
+	GIT_UNUSED(opts);
+	GIT_UNUSED(settings);
+	SSL_load_error_strings();
+	SSL_library_init();
+	return 0;
+}
+
+BIO_METHOD* BIO_meth_new__legacy(int type, const char *name)
+{
+	BIO_METHOD *meth = git__calloc(1, sizeof(BIO_METHOD));
+	if (!meth) {
+		return NULL;
+	}
+
+	meth->type = type;
+	meth->name = name;
+
+	return meth;
+}
+
+void BIO_meth_free__legacy(BIO_METHOD *biom)
+{
+	git__free(biom);
+}
+
+int BIO_meth_set_write__legacy(BIO_METHOD *biom, int (*write) (BIO *, const char *, int))
+{
+	biom->bwrite = write;
+	return 1;
+}
+
+int BIO_meth_set_read__legacy(BIO_METHOD *biom, int (*read) (BIO *, char *, int))
+{
+	biom->bread = read;
+	return 1;
+}
+
+int BIO_meth_set_puts__legacy(BIO_METHOD *biom, int (*puts) (BIO *, const char *))
+{
+	biom->bputs = puts;
+	return 1;
+}
+
+int BIO_meth_set_gets__legacy(BIO_METHOD *biom, int (*gets) (BIO *, char *, int))
+
+{
+	biom->bgets = gets;
+	return 1;
+}
+
+int BIO_meth_set_ctrl__legacy(BIO_METHOD *biom, long (*ctrl) (BIO *, int, long, void *))
+{
+	biom->ctrl = ctrl;
+	return 1;
+}
+
+int BIO_meth_set_create__legacy(BIO_METHOD *biom, int (*create) (BIO *))
+{
+	biom->create = create;
+	return 1;
+}
+
+int BIO_meth_set_destroy__legacy(BIO_METHOD *biom, int (*destroy) (BIO *))
+{
+	biom->destroy = destroy;
+	return 1;
+}
+
+int BIO_get_new_index__legacy(void)
+{
+	/* This exists as of 1.1 so before we'd just have 0 */
+	return 0;
+}
+
+void BIO_set_init__legacy(BIO *b, int init)
+{
+	b->init = init;
+}
+
+void BIO_set_data__legacy(BIO *a, void *ptr)
+{
+	a->ptr = ptr;
+}
+
+void *BIO_get_data__legacy(BIO *a)
+{
+	return a->ptr;
+}
+
+const unsigned char *ASN1_STRING_get0_data__legacy(const ASN1_STRING *x)
+{
+	return ASN1_STRING_data((ASN1_STRING *)x);
+}
+
+long SSL_CTX_set_options__legacy(SSL_CTX *ctx, long op)
+{
+	return SSL_CTX_ctrl(ctx, SSL_CTRL_OPTIONS, op, NULL);
+}
+
+# if defined(GIT_THREADS)
+static git_mutex *openssl_locks;
+
+static void openssl_locking_function(int mode, int n, const char *file, int line)
+{
+	int lock;
+
+	GIT_UNUSED(file);
+	GIT_UNUSED(line);
+
+	lock = mode & CRYPTO_LOCK;
+
+	if (lock)
+		(void)git_mutex_lock(&openssl_locks[n]);
+	else
+		git_mutex_unlock(&openssl_locks[n]);
+}
+
+static void shutdown_ssl_locking(void)
+{
+	int num_locks, i;
+
+	num_locks = CRYPTO_num_locks();
+	CRYPTO_set_locking_callback(NULL);
+
+	for (i = 0; i < num_locks; ++i)
+		git_mutex_free(&openssl_locks[i]);
+	git__free(openssl_locks);
+}
+
+static void threadid_cb(CRYPTO_THREADID *threadid)
+{
+	GIT_UNUSED(threadid);
+	CRYPTO_THREADID_set_numeric(threadid, git_thread_currentid());
+}
+
+int git_openssl_set_locking(void)
+{
+	int num_locks, i;
+
+#ifndef GIT_THREADS
+	git_error_set(GIT_ERROR_THREAD, "libgit2 was not built with threads");
+	return -1;
+#endif
+
+#ifdef GIT_OPENSSL_DYNAMIC
+	/*
+	 * This function is required on legacy versions of OpenSSL; when building
+	 * with dynamically-loaded OpenSSL, we detect whether we loaded it or not.
+	 */
+	if (!CRYPTO_set_locking_callback)
+		return 0;
+#endif
+
+	CRYPTO_THREADID_set_callback(threadid_cb);
+
+	num_locks = CRYPTO_num_locks();
+	openssl_locks = git__calloc(num_locks, sizeof(git_mutex));
+	GIT_ERROR_CHECK_ALLOC(openssl_locks);
+
+	for (i = 0; i < num_locks; i++) {
+		if (git_mutex_init(&openssl_locks[i]) != 0) {
+			git_error_set(GIT_ERROR_SSL, "failed to initialize openssl locks");
+			return -1;
+		}
+	}
+
+	CRYPTO_set_locking_callback(openssl_locking_function);
+	return git_runtime_shutdown_register(shutdown_ssl_locking);
+}
+#endif /* GIT_THREADS */
+
+#endif /* GIT_OPENSSL_LEGACY || GIT_OPENSSL_DYNAMIC */
diff --git a/src/streams/openssl_legacy.h b/src/streams/openssl_legacy.h
new file mode 100644
index 000000000..1f74fd95a
--- /dev/null
+++ b/src/streams/openssl_legacy.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_streams_openssl_legacy_h__
+#define INCLUDE_streams_openssl_legacy_h__
+
+#include "streams/openssl_dynamic.h"
+
+#if defined(GIT_OPENSSL) && !defined(GIT_OPENSSL_DYNAMIC)
+# include <openssl/ssl.h>
+# include <openssl/err.h>
+# include <openssl/x509v3.h>
+# include <openssl/bio.h>
+
+# if (defined(OPENSSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER < 0x10100000L) || \
+     (defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x20700000L)
+#  define GIT_OPENSSL_LEGACY
+# endif
+#endif
+
+#if defined(GIT_OPENSSL_LEGACY) && !defined(GIT_OPENSSL_DYNAMIC)
+# define OPENSSL_init_ssl OPENSSL_init_ssl__legacy
+# define BIO_meth_new BIO_meth_new__legacy
+# define BIO_meth_free BIO_meth_free__legacy
+# define BIO_meth_set_write BIO_meth_set_write__legacy
+# define BIO_meth_set_read BIO_meth_set_read__legacy
+# define BIO_meth_set_puts BIO_meth_set_puts__legacy
+# define BIO_meth_set_gets BIO_meth_set_gets__legacy
+# define BIO_meth_set_ctrl BIO_meth_set_ctrl__legacy
+# define BIO_meth_set_create BIO_meth_set_create__legacy
+# define BIO_meth_set_destroy BIO_meth_set_destroy__legacy
+# define BIO_get_new_index BIO_get_new_index__legacy
+# define BIO_set_data BIO_set_data__legacy
+# define BIO_set_init BIO_set_init__legacy
+# define BIO_get_data BIO_get_data__legacy
+# define ASN1_STRING_get0_data ASN1_STRING_get0_data__legacy
+#endif
+
+#if defined(GIT_OPENSSL_LEGACY) || defined(GIT_OPENSSL_DYNAMIC)
+
+extern int OPENSSL_init_ssl__legacy(uint64_t opts, const void *settings);
+extern BIO_METHOD* BIO_meth_new__legacy(int type, const char *name);
+extern void BIO_meth_free__legacy(BIO_METHOD *biom);
+extern int BIO_meth_set_write__legacy(BIO_METHOD *biom, int (*write) (BIO *, const char *, int));
+extern int BIO_meth_set_read__legacy(BIO_METHOD *biom, int (*read) (BIO *, char *, int));
+extern int BIO_meth_set_puts__legacy(BIO_METHOD *biom, int (*puts) (BIO *, const char *));
+extern int BIO_meth_set_gets__legacy(BIO_METHOD *biom, int (*gets) (BIO *, char *, int));
+extern int BIO_meth_set_ctrl__legacy(BIO_METHOD *biom, long (*ctrl) (BIO *, int, long, void *));
+extern int BIO_meth_set_create__legacy(BIO_METHOD *biom, int (*create) (BIO *));
+extern int BIO_meth_set_destroy__legacy(BIO_METHOD *biom, int (*destroy) (BIO *));
+extern int BIO_get_new_index__legacy(void);
+extern void BIO_set_data__legacy(BIO *a, void *ptr);
+extern void BIO_set_init__legacy(BIO *b, int init);
+extern void *BIO_get_data__legacy(BIO *a);
+extern const unsigned char *ASN1_STRING_get0_data__legacy(const ASN1_STRING *x);
+extern long SSL_CTX_set_options__legacy(SSL_CTX *ctx, long op);
+
+#endif
+
+#endif
diff --git a/src/transports/auth_ntlm.c b/src/transports/auth_ntlm.c
index e0960bf9d..b5110616b 100644
--- a/src/transports/auth_ntlm.c
+++ b/src/transports/auth_ntlm.c
@@ -14,7 +14,7 @@
 
 #ifdef GIT_NTLM
 
-#include "ntlm.h"
+#include "ntlmclient.h"
 
 typedef struct {
 	git_http_auth_context parent;
diff --git a/tests/main.c b/tests/main.c
index 207a6a8be..56751c288 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -18,7 +18,9 @@ int main(int argc, char *argv[])
 
 	res = git_libgit2_init();
 	if (res < 0) {
-		fprintf(stderr, "failed to init libgit2");
+		const git_error *err = git_error_last();
+		const char *msg = err ? err->message : "unknown failure";
+		fprintf(stderr, "failed to init libgit2: %s\n", msg);
 		return res;
 	}