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Fix for EXP-RC2-CBC-MD5

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MD5 should use little endian order. Fortunately the only ciphersuite
affected is EXP-RC2-CBC-MD5 (TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5) which
is a rarely used export grade ciphersuite.
This commit is contained in:
Adam Langley
2013-02-06 16:05:40 +00:00
committed by Dr. Stephen Henson
parent 41cf07f0ec
commit f306b87d76
2 changed files with 47 additions and 9 deletions
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39
ssl/s3_cbc.c
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@@ -328,16 +328,24 @@ void ssl3_cbc_copy_mac(unsigned char* out,
#endif
}
/* u32toLE serialises an unsigned, 32-bit number (n) as four bytes at (p) in
* little-endian order. The value of p is advanced by four. */
#define u32toLE(n, p) \
(*((p)++)=(unsigned char)(n), \
*((p)++)=(unsigned char)(n>>8), \
*((p)++)=(unsigned char)(n>>16), \
*((p)++)=(unsigned char)(n>>24))
/* These functions serialize the state of a hash and thus perform the standard
* "final" operation without adding the padding and length that such a function
* typically does. */
static void tls1_md5_final_raw(void* ctx, unsigned char *md_out)
{
MD5_CTX *md5 = ctx;
l2n(md5->A, md_out);
l2n(md5->B, md_out);
l2n(md5->C, md_out);
l2n(md5->D, md_out);
u32toLE(md5->A, md_out);
u32toLE(md5->B, md_out);
u32toLE(md5->C, md_out);
u32toLE(md5->D, md_out);
}
static void tls1_sha1_final_raw(void* ctx, unsigned char *md_out)
@@ -457,6 +465,7 @@ void ssl3_cbc_digest_record(
/* mdLengthSize is the number of bytes in the length field that terminates
* the hash. */
unsigned md_length_size = 8;
char length_is_big_endian = 1;
/* This is a, hopefully redundant, check that allows us to forget about
* many possible overflows later in this function. */
@@ -470,6 +479,7 @@ void ssl3_cbc_digest_record(
md_transform = (void(*)(void *ctx, const unsigned char *block)) MD5_Transform;
md_size = 16;
sslv3_pad_length = 48;
length_is_big_endian = 0;
break;
case NID_sha1:
SHA1_Init((SHA_CTX*)md_state.c);
@@ -610,11 +620,22 @@ void ssl3_cbc_digest_record(
md_transform(md_state.c, hmac_pad);
}
memset(length_bytes,0,md_length_size-4);
length_bytes[md_length_size-4] = (unsigned char)(bits>>24);
length_bytes[md_length_size-3] = (unsigned char)(bits>>16);
length_bytes[md_length_size-2] = (unsigned char)(bits>>8);
length_bytes[md_length_size-1] = (unsigned char)bits;
if (length_is_big_endian)
{
memset(length_bytes,0,md_length_size-4);
length_bytes[md_length_size-4] = (unsigned char)(bits>>24);
length_bytes[md_length_size-3] = (unsigned char)(bits>>16);
length_bytes[md_length_size-2] = (unsigned char)(bits>>8);
length_bytes[md_length_size-1] = (unsigned char)bits;
}
else
{
memset(length_bytes,0,md_length_size);
length_bytes[md_length_size-5] = (unsigned char)(bits>>24);
length_bytes[md_length_size-6] = (unsigned char)(bits>>16);
length_bytes[md_length_size-7] = (unsigned char)(bits>>8);
length_bytes[md_length_size-8] = (unsigned char)bits;
}
if (k > 0)
{