From 4b2b878ddd08a6a56ed35b489d161da3cbc16b1f Mon Sep 17 00:00:00 2001
From: Nikos Mavrogiannopoulos <nmav@redhat.com>
Date: Mon, 14 Nov 2016 14:47:13 +0100
Subject: PKCS#5,7 decryption: enforce limits in the support parameter sizes

This allows to detect invalid parameters early rather than later.
Relates #148
---
 lib/x509/pkcs7-crypt.c         | 38 ++++++++++++++++++++++++++++----------
 lib/x509/privkey_pkcs8_pbes1.c |  5 +++++
 lib/x509/x509_int.h            |  4 ++--
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/lib/x509/pkcs7-crypt.c b/lib/x509/pkcs7-crypt.c
index 4eecc29146..2d2e170bfd 100644
--- a/lib/x509/pkcs7-crypt.c
+++ b/lib/x509/pkcs7-crypt.c
@@ -647,6 +647,11 @@ read_pbkdf2_params(ASN1_TYPE pasn,
 	}
 	_gnutls_hard_log("salt.specified.size: %d\n", params->salt_size);
 
+	if (params->salt_size < 0) {
+		result = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
+		goto error;
+	}
+
 	/* read the iteration count 
 	 */
 	result =
@@ -656,6 +661,12 @@ read_pbkdf2_params(ASN1_TYPE pasn,
 		gnutls_assert();
 		goto error;
 	}
+
+	if (params->iter_count >= INT_MAX || params->iter_count == 0) {
+		result = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
+		goto error;
+	}
+
 	_gnutls_hard_log("iterationCount: %d\n", params->iter_count);
 
 	/* read the keylength, if it is set.
@@ -665,6 +676,12 @@ read_pbkdf2_params(ASN1_TYPE pasn,
 	if (result < 0) {
 		params->key_size = 0;
 	}
+
+	if (params->key_size > MAX_CIPHER_KEY_SIZE) {
+		result = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
+		goto error;
+	}
+
 	_gnutls_hard_log("keyLength: %d\n", params->key_size);
 
 	len = sizeof(oid);
@@ -705,28 +722,29 @@ static int read_pkcs12_kdf_params(ASN1_TYPE pasn, struct pbkdf2_params *params)
 	    asn1_read_value(pasn, "salt", params->salt, &params->salt_size);
 	if (result != ASN1_SUCCESS) {
 		gnutls_assert();
-		result = _gnutls_asn2err(result);
-		goto error;
+		return _gnutls_asn2err(result);
 	}
+
+	if (params->salt_size < 0)
+		return gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
+
 	_gnutls_hard_log("salt.size: %d\n", params->salt_size);
 
 	/* read the iteration count 
 	 */
 	result =
 	    _gnutls_x509_read_uint(pasn, "iterations", &params->iter_count);
-	if (result < 0) {
-		gnutls_assert();
-		goto error;
-	}
+	if (result < 0)
+		return gnutls_assert_val(result);
+
+	if (params->iter_count >= INT_MAX || params->iter_count == 0)
+		return gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
+
 	_gnutls_hard_log("iterationCount: %d\n", params->iter_count);
 
 	params->key_size = 0;
 
 	return 0;
-
- error:
-	return result;
-
 }
 
 /* Writes the PBE parameters for PKCS-12 schemas.
diff --git a/lib/x509/privkey_pkcs8_pbes1.c b/lib/x509/privkey_pkcs8_pbes1.c
index d621851365..933363d37c 100644
--- a/lib/x509/privkey_pkcs8_pbes1.c
+++ b/lib/x509/privkey_pkcs8_pbes1.c
@@ -74,6 +74,11 @@ int _gnutls_read_pbkdf1_params(const uint8_t * data, int data_size,
 		goto error;
 	}
 
+	if (kdf_params->iter_count >= INT_MAX || kdf_params->iter_count == 0) {
+		ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
+		goto error;
+	}
+
 	len = sizeof(kdf_params->salt);
 	result =
 	    asn1_read_value(pasn, "salt",
diff --git a/lib/x509/x509_int.h b/lib/x509/x509_int.h
index 4fe0e3dc2a..198a69d500 100644
--- a/lib/x509/x509_int.h
+++ b/lib/x509/x509_int.h
@@ -116,8 +116,8 @@ typedef struct gnutls_pkcs7_int {
 struct pbkdf2_params {
 	uint8_t salt[32];
 	int salt_size;
-	unsigned int iter_count;
-	unsigned int key_size;
+	unsigned iter_count;
+	unsigned key_size;
 	gnutls_mac_algorithm_t mac;
 };
 
-- 
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