Don't access memory before checking the correct length in aesni_cbc_hmac_sha256_ctrl...

[openssl.git] / crypto / evp / e_aes_cbc_hmac_sha256.c

diff --git a/crypto/evp/e_aes_cbc_hmac_sha256.c b/crypto/evp/e_aes_cbc_hmac_sha256.c
index 5a92e0b85dda81ab1e1d98fe4d9197f6018b42f3..bef603a3a5970f06a315bac571edc83e6489916c 100644 (file)
--- a/crypto/evp/e_aes_cbc_hmac_sha256.c
+++ b/crypto/evp/e_aes_cbc_hmac_sha256.c
@@ -552,7 +552,7 @@ static int aesni_cbc_hmac_sha256_cipher(EVP_CIPHER_CTX *ctx,
             key->md = key->head;
             SHA256_Update(&key->md, key->aux.tls_aad, plen);
 
-# if 1
+# if 1      /* see original reference version in #else */
             len -= SHA256_DIGEST_LENGTH; /* amend mac */
             if (len >= (256 + SHA256_CBLOCK)) {
                 j = (len - (256 + SHA256_CBLOCK)) & (0 - SHA256_CBLOCK);
@@ -680,7 +680,7 @@ static int aesni_cbc_hmac_sha256_cipher(EVP_CIPHER_CTX *ctx,
                 for (; inp_blocks < pad_blocks; inp_blocks++)
                     sha1_block_data_order(&key->md, data, 1);
             }
-# endif
+# endif      /* pre-lucky-13 reference version of above */
             key->md = key->tail;
             SHA256_Update(&key->md, pmac->c, SHA256_DIGEST_LENGTH);
             SHA256_Final(pmac->c, &key->md);
@@ -688,7 +688,7 @@ static int aesni_cbc_hmac_sha256_cipher(EVP_CIPHER_CTX *ctx,
             /* verify HMAC */
             out += inp_len;
             len -= inp_len;
-# if 1
+# if 1      /* see original reference version in #else */
             {
                 unsigned char *p =
                     out + len - 1 - maxpad - SHA256_DIGEST_LENGTH;
@@ -711,7 +711,7 @@ static int aesni_cbc_hmac_sha256_cipher(EVP_CIPHER_CTX *ctx,
                 res = 0 - ((0 - res) >> (sizeof(res) * 8 - 1));
                 ret &= (int)~res;
             }
-# else
+# else      /* pre-lucky-13 reference version of above */
             for (res = 0, i = 0; i < SHA256_DIGEST_LENGTH; i++)
                 res |= out[i] ^ pmac->c[i];
             res = 0 - ((0 - res) >> (sizeof(res) * 8 - 1));
@@ -777,11 +777,13 @@ static int aesni_cbc_hmac_sha256_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg,
     case EVP_CTRL_AEAD_TLS1_AAD:
         {
             unsigned char *p = ptr;
-            unsigned int len = p[arg - 2] << 8 | p[arg - 1];
+            unsigned int len;
 
             if (arg != EVP_AEAD_TLS1_AAD_LEN)
                 return -1;
 
+            len = p[arg - 2] << 8 | p[arg - 1];
+
             if (EVP_CIPHER_CTX_encrypting(ctx)) {
                 key->payload_length = len;
                 if ((key->aux.tls_ver =