5 files changed, 59 insertions, 0 deletions
diff --git a/include/git2/errors.h b/include/git2/errors.h
index b91560631..2ba9924f5 100644
--- a/include/git2/errors.h
+++ b/include/git2/errors.h
@@ -42,6 +42,7 @@ typedef enum {
 	GIT_ELOCKED         = -14,	/**< Lock file prevented operation */
 	GIT_EMODIFIED       = -15,	/**< Reference value does not match expected */
 	GIT_EAUTH           = -16,      /**< Authentication error */
+	GIT_ECERTIFICATE    = -17,      /**< Server certificate is invalid */
 
 	GIT_PASSTHROUGH     = -30,	/**< Internal only */
 	GIT_ITEROVER        = -31,	/**< Signals end of iteration with iterator */
diff --git a/include/git2/remote.h b/include/git2/remote.h
index c0717fa31..723147590 100644
--- a/include/git2/remote.h
+++ b/include/git2/remote.h
@@ -459,6 +459,14 @@ struct git_remote_callbacks {
 	git_cred_acquire_cb credentials;
 
 	/**
+	 * If cert verification fails, this will be called to let the
+	 * user make the final decision of whether to allow the
+	 * connection to proceed. Returns 1 to allow the connection, 0
+	 * to disallow it or a negative value to indicate an error.
+	 */
+        git_transport_certificate_check_cb certificate_check;
+
+	/**
 	 * During the download of new data, this will be regularly
 	 * called with the current count of progress done by the
 	 * indexer.
diff --git a/include/git2/sys/transport.h b/include/git2/sys/transport.h
index 62ac455d3..44d41c14d 100644
--- a/include/git2/sys/transport.h
+++ b/include/git2/sys/transport.h
@@ -37,6 +37,7 @@ struct git_transport {
 		git_transport *transport,
 		git_transport_message_cb progress_cb,
 		git_transport_message_cb error_cb,
+		git_transport_certificate_check_cb certificate_check_cb,
 		void *payload);
 
 	/* Connect the transport to the remote repository, using the given
diff --git a/include/git2/transport.h b/include/git2/transport.h
index 7090698ac..cd4429fee 100644
--- a/include/git2/transport.h
+++ b/include/git2/transport.h
@@ -20,6 +20,43 @@
  */
 GIT_BEGIN_DECL
 
+/**
+ * Type of host certificate structure that is passed to the check callback
+ */
+typedef enum git_cert_t {
+        /**
+         * The `data` argument to the callback will be a pointer to
+         * OpenSSL's `X509` structure.
+         */
+	GIT_CERT_X509_OPENSSL,
+	GIT_CERT_X509_WINHTTP,
+        /**
+         * The `data` argument to the callback will be a pointer to a
+         * `git_cert_hostkey` structure.
+         */
+	GIT_CERT_HOSTKEY_LIBSSH2,
+} git_cert_t;
+
+/**
+ * Hostkey information taken from libssh2
+ */
+typedef struct {
+        /**
+         * A hostkey type from libssh2, either
+         * `LIBSSH2_HOSTKEY_HASH_MD5` or `LIBSSH2_HOSTKEY_HASH_SHA1`
+         */
+        int type;
+        /**
+         * Hostkey hash. If the type is MD5, only the first 16 bytes
+         * will be set.
+         */
+        unsigned char hash[20];
+} git_cert_hostkey;
+
+/*
+ *** Begin interface for credentials acquisition ***
+ */
+
 /** Authentication type requested */
 typedef enum {
 	/* git_cred_userpass_plaintext */
diff --git a/include/git2/types.h b/include/git2/types.h
index 7ed1bcd4c..0009a8aa5 100644
--- a/include/git2/types.h
+++ b/include/git2/types.h
@@ -253,6 +253,18 @@ typedef int (*git_transfer_progress_cb)(const git_transfer_progress *stats, void
  */
 typedef int (*git_transport_message_cb)(const char *str, int len, void *payload);
 
+
+typedef enum git_cert_t git_cert_t;
+
+/**
+ * Callback for the user's custom certificate checks.
+ *
+ * @param type The type of certificate or host info, SSH or X.509
+ * @param data The data for the certificate or host info
+ * @param payload Payload provided by the caller
+ */
+typedef int (*git_transport_certificate_check_cb)(git_cert_t type, void *data, void *payload);
+
 /**
  * Opaque structure representing a submodule.
  */