Permalink
Browse files

Check that we have enough padding characters.

Reviewed-by: Emilia Käsper <emilia@openssl.org>

CVE-2016-2107

MR: #2572
  • Loading branch information...
kroeckx authored and mattcaswell committed Apr 16, 2016
1 parent 2c7fe4d commit 70428eada9bc4cf31424d723d1f992baffeb0dfb
Showing with 6 additions and 0 deletions.
  1. +3 −0 crypto/evp/e_aes_cbc_hmac_sha1.c
  2. +3 −0 crypto/evp/e_aes_cbc_hmac_sha256.c
@@ -59,6 +59,7 @@
#include <openssl/rand.h>
#include "modes_lcl.h"
#include "internal/evp_int.h"
+#include "internal/constant_time_locl.h"
#ifndef EVP_CIPH_FLAG_AEAD_CIPHER
# define EVP_CIPH_FLAG_AEAD_CIPHER 0x200000
@@ -583,6 +584,8 @@ static int aesni_cbc_hmac_sha1_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
maxpad |= (255 - maxpad) >> (sizeof(maxpad) * 8 - 8);
maxpad &= 255;
+ ret &= constant_time_ge(maxpad, pad);
+
inp_len = len - (SHA_DIGEST_LENGTH + pad + 1);
mask = (0 - ((inp_len - len) >> (sizeof(inp_len) * 8 - 1)));
inp_len &= mask;
@@ -59,6 +59,7 @@
#include <openssl/sha.h>
#include <openssl/rand.h>
#include "modes_lcl.h"
+#include "internal/constant_time_locl.h"
#include "internal/evp_int.h"
#ifndef EVP_CIPH_FLAG_AEAD_CIPHER
@@ -594,6 +595,8 @@ static int aesni_cbc_hmac_sha256_cipher(EVP_CIPHER_CTX *ctx,
maxpad |= (255 - maxpad) >> (sizeof(maxpad) * 8 - 8);
maxpad &= 255;
+ ret &= constant_time_ge(maxpad, pad);
+
inp_len = len - (SHA256_DIGEST_LENGTH + pad + 1);
mask = (0 - ((inp_len - len) >> (sizeof(inp_len) * 8 - 1)));
inp_len &= mask;

1 comment on commit 70428ea

@FeeiCN

This comment has been minimized.

Show comment
Hide comment

FeeiCN commented on 70428ea May 9, 2016

god

Please sign in to comment.