File openssl-CVE-2017-3731.patch of Package openssl
commit 51d009043670a627d6abe66894126851cf3690e9
Author: Andy Polyakov <appro@openssl.org>
Date: Thu Jan 19 00:17:30 2017 +0100
crypto/evp: harden RC4_MD5 cipher.
Originally a crash in 32-bit build was reported CHACHA20-POLY1305
cipher. The crash is triggered by truncated packet and is result
of excessive hashing to the edge of accessible memory (or bogus
MAC value is produced if x86 MD5 assembly module is involved). Since
hash operation is read-only it is not considered to be exploitable
beyond a DoS condition.
Thanks to Robert Święcki for report.
CVE-2017-3731
Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/crypto/evp/e_rc4_hmac_md5.c b/crypto/evp/e_rc4_hmac_md5.c
index 5e92855..93cfe3f 100644
--- a/crypto/evp/e_rc4_hmac_md5.c
+++ b/crypto/evp/e_rc4_hmac_md5.c
@@ -269,6 +269,8 @@ static int rc4_hmac_md5_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg,
len = p[arg - 2] << 8 | p[arg - 1];
if (!ctx->encrypt) {
+ if (len < MD5_DIGEST_LENGTH)
+ return -1;
len -= MD5_DIGEST_LENGTH;
p[arg - 2] = len >> 8;
p[arg - 1] = len;