The branch OpenSSL_1_0_1-stable has been updated via 1bbe48ab149893a78bf99c8eb8895c928900a16f (commit) from 3612ff6fcec0e3d1f2a598135fe12177c0419582 (commit)
- Log ----------------------------------------------------------------- commit 1bbe48ab149893a78bf99c8eb8895c928900a16f Author: Dr. Stephen Henson <st...@openssl.org> Date: Tue Aug 23 18:14:54 2016 +0100 Sanity check ticket length. If a ticket callback changes the HMAC digest to SHA512 the existing sanity checks are not sufficient and an attacker could perform a DoS attack with a malformed ticket. Add additional checks based on HMAC size. Thanks to Shi Lei for reporting this bug. CVE-2016-6302 Reviewed-by: Rich Salz <rs...@openssl.org> (cherry picked from commit baaabfd8fdcec04a691695fad9a664bea43202b6) ----------------------------------------------------------------------- Summary of changes: ssl/t1_lib.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c index d961e4a..7680491 100644 --- a/ssl/t1_lib.c +++ b/ssl/t1_lib.c @@ -2273,9 +2273,7 @@ static int tls_decrypt_ticket(SSL *s, const unsigned char *etick, HMAC_CTX hctx; EVP_CIPHER_CTX ctx; SSL_CTX *tctx = s->initial_ctx; - /* Need at least keyname + iv + some encrypted data */ - if (eticklen < 48) - return 2; + /* Initialize session ticket encryption and HMAC contexts */ HMAC_CTX_init(&hctx); EVP_CIPHER_CTX_init(&ctx); @@ -2309,6 +2307,13 @@ static int tls_decrypt_ticket(SSL *s, const unsigned char *etick, if (mlen < 0) { goto err; } + /* Sanity check ticket length: must exceed keyname + IV + HMAC */ + if (eticklen <= 16 + EVP_CIPHER_CTX_iv_length(&ctx) + mlen) { + HMAC_CTX_cleanup(&hctx); + EVP_CIPHER_CTX_cleanup(&ctx); + return 2; + } + eticklen -= mlen; /* Check HMAC of encrypted ticket */ if (HMAC_Update(&hctx, etick, eticklen) <= 0 _____ openssl-commits mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-commits