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Check that we have enough padding characters.

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

CVE-2016-2107

MR: #2572
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kroeckx authored and mattcaswell committed Apr 16, 2016
1 parent 643e8e9 commit 68595c0c2886e7942a14f98c17a55a88afb6c292
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
@@ -60,6 +60,7 @@
# include <openssl/sha.h>
# include <openssl/rand.h>
# include "modes_lcl.h"
# include "constant_time_locl.h"
# ifndef EVP_CIPH_FLAG_AEAD_CIPHER
# define EVP_CIPH_FLAG_AEAD_CIPHER 0x200000
@@ -578,6 +579,8 @@ 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;
@@ -60,6 +60,7 @@
# include <openssl/sha.h>
# include <openssl/rand.h>
# include "modes_lcl.h"
# include "constant_time_locl.h"
# ifndef EVP_CIPH_FLAG_AEAD_CIPHER
# define EVP_CIPH_FLAG_AEAD_CIPHER 0x200000
@@ -589,6 +590,8 @@ 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;

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