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authorJung-uk Kim <jkim@FreeBSD.org>2014-10-15 17:32:57 +0000
committerJung-uk Kim <jkim@FreeBSD.org>2014-10-15 17:32:57 +0000
commit58ab7656b2c140e06d60a7831a9f5b6e1ddc2fe5 (patch)
tree6195ffd39cd3e0b3d6c711f6531b3e7e13b85b44 /crypto/evp/evp_enc.c
parentcb6864802ed26a1031701a6a385961592a5cac25 (diff)
downloadsrc-58ab7656b2c140e06d60a7831a9f5b6e1ddc2fe5.tar.gz
src-58ab7656b2c140e06d60a7831a9f5b6e1ddc2fe5.zip
Import OpenSSL 1.0.1j.vendor/openssl/1.0.1j
Notes
Notes: svn path=/vendor-crypto/openssl/dist/; revision=273138 svn path=/vendor-crypto/openssl/1.0.1j/; revision=273139; tag=vendor/openssl/1.0.1j
Diffstat (limited to 'crypto/evp/evp_enc.c')
-rw-r--r--crypto/evp/evp_enc.c56
1 files changed, 31 insertions, 25 deletions
diff --git a/crypto/evp/evp_enc.c b/crypto/evp/evp_enc.c
index 0c54f05e6ef5..7b1842a52a6d 100644
--- a/crypto/evp/evp_enc.c
+++ b/crypto/evp/evp_enc.c
@@ -67,6 +67,7 @@
#ifdef OPENSSL_FIPS
#include <openssl/fips.h>
#endif
+#include "constant_time_locl.h"
#include "evp_locl.h"
#ifdef OPENSSL_FIPS
@@ -500,21 +501,21 @@ int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
{
- int i,n;
- unsigned int b;
+ unsigned int i, b;
+ unsigned char pad, padding_good;
*outl=0;
if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER)
{
- i = M_do_cipher(ctx, out, NULL, 0);
- if (i < 0)
+ int ret = M_do_cipher(ctx, out, NULL, 0);
+ if (ret < 0)
return 0;
else
- *outl = i;
+ *outl = ret;
return 1;
}
- b=ctx->cipher->block_size;
+ b=(unsigned int)(ctx->cipher->block_size);
if (ctx->flags & EVP_CIPH_NO_PADDING)
{
if(ctx->buf_len)
@@ -533,28 +534,34 @@ int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
return(0);
}
OPENSSL_assert(b <= sizeof ctx->final);
- n=ctx->final[b-1];
- if (n == 0 || n > (int)b)
- {
- EVPerr(EVP_F_EVP_DECRYPTFINAL_EX,EVP_R_BAD_DECRYPT);
- return(0);
- }
- for (i=0; i<n; i++)
+ pad=ctx->final[b-1];
+
+ padding_good = (unsigned char)(~constant_time_is_zero_8(pad));
+ padding_good &= constant_time_ge_8(b, pad);
+
+ for (i = 1; i < b; ++i)
{
- if (ctx->final[--b] != n)
- {
- EVPerr(EVP_F_EVP_DECRYPTFINAL_EX,EVP_R_BAD_DECRYPT);
- return(0);
- }
+ unsigned char is_pad_index = constant_time_lt_8(i, pad);
+ unsigned char pad_byte_good = constant_time_eq_8(ctx->final[b-i-1], pad);
+ padding_good &= constant_time_select_8(is_pad_index, pad_byte_good, 0xff);
}
- n=ctx->cipher->block_size-n;
- for (i=0; i<n; i++)
- out[i]=ctx->final[i];
- *outl=n;
+
+ /*
+ * At least 1 byte is always padding, so we always write b - 1
+ * bytes to avoid a timing leak. The caller is required to have |b|
+ * bytes space in |out| by the API contract.
+ */
+ for (i = 0; i < b - 1; ++i)
+ out[i] = ctx->final[i] & padding_good;
+ /* Safe cast: for a good padding, EVP_MAX_IV_LENGTH >= b >= pad */
+ *outl = padding_good & ((unsigned char)(b - pad));
+ return padding_good & 1;
}
else
- *outl=0;
- return(1);
+ {
+ *outl = 0;
+ return 1;
+ }
}
void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx)
@@ -678,4 +685,3 @@ int EVP_CIPHER_CTX_copy(EVP_CIPHER_CTX *out, const EVP_CIPHER_CTX *in)
return in->cipher->ctrl((EVP_CIPHER_CTX *)in, EVP_CTRL_COPY, 0, out);
return 1;
}
-