diff options
| author | Matt Caswell <matt@openssl.org> | 2018-02-20 10:20:20 +0000 |
|---|---|---|
| committer | Matt Caswell <matt@openssl.org> | 2018-02-21 11:19:11 +0000 |
| commit | ee763495250b29fd32cb4026f17678ba30a59342 (patch) | |
| tree | 1e1b16cb83733d283fa1342eb63c7549a1266471 | |
| parent | c7a47adca29e1ec761d639dd75336bb36ebf4a9b (diff) | |
Sanity check the ticket length before using key name/IV
This could in theory result in an overread - but due to the over allocation
of the underlying buffer does not represent a security issue.
Thanks to Fedor Indutny for reporting this issue.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/5414)
| -rw-r--r-- | ssl/t1_lib.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c index 3965be9d90..57f9559993 100644 --- a/ssl/t1_lib.c +++ b/ssl/t1_lib.c @@ -1280,9 +1280,15 @@ TICKET_RETURN tls_decrypt_ticket(SSL *s, const unsigned char *etick, size_t mlen; unsigned char tick_hmac[EVP_MAX_MD_SIZE]; HMAC_CTX *hctx = NULL; - EVP_CIPHER_CTX *ctx; + EVP_CIPHER_CTX *ctx = NULL; SSL_CTX *tctx = s->session_ctx; + /* Need at least keyname + iv */ + if (eticklen < TLSEXT_KEYNAME_LENGTH + EVP_MAX_IV_LENGTH) { + ret = TICKET_NO_DECRYPT; + goto err; + } + /* Initialize session ticket encryption and HMAC contexts */ hctx = HMAC_CTX_new(); if (hctx == NULL) @@ -1294,8 +1300,9 @@ TICKET_RETURN tls_decrypt_ticket(SSL *s, const unsigned char *etick, } if (tctx->ext.ticket_key_cb) { unsigned char *nctick = (unsigned char *)etick; - int rv = tctx->ext.ticket_key_cb(s, nctick, nctick + 16, - ctx, hctx, 0); + int rv = tctx->ext.ticket_key_cb(s, nctick, + nctick + TLSEXT_KEYNAME_LENGTH, + ctx, hctx, 0); if (rv < 0) goto err; if (rv == 0) { @@ -1307,7 +1314,7 @@ TICKET_RETURN tls_decrypt_ticket(SSL *s, const unsigned char *etick, } else { /* Check key name matches */ if (memcmp(etick, tctx->ext.tick_key_name, - sizeof(tctx->ext.tick_key_name)) != 0) { + TLSEXT_KEYNAME_LENGTH) != 0) { ret = TICKET_NO_DECRYPT; goto err; } @@ -1316,8 +1323,7 @@ TICKET_RETURN tls_decrypt_ticket(SSL *s, const unsigned char *etick, EVP_sha256(), NULL) <= 0 || EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, tctx->ext.tick_aes_key, - etick - + sizeof(tctx->ext.tick_key_name)) <= 0) { + etick + TLSEXT_KEYNAME_LENGTH) <= 0) { goto err; } } |