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ensure that ciphersuite strings such as "RC4-MD5" match the SSL 2.0

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ciphersuite as well
This commit is contained in:
Bodo Möller 2006-09-11 09:48:46 +00:00
parent 40ddcb717a
commit 879b30aaa3
2 changed files with 42 additions and 12 deletions
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26
CHANGES
View file

@ -4,6 +4,32 @@
Changes between 0.9.8c and 0.9.8d [xx XXX xxxx]
*) Since 0.9.8b, ciphersuite strings naming explicit ciphersuites
match only those. Before that, "AES256-SHA" would be interpreted
as a pattern and match "AES128-SHA" too since we currently only
have a single AES bit in the ciphersuite description bitmap.
That change, however, also applied to ciphersuite strings such as
"RC4-MD5" that intentionally matched multiple ciphersuites --
namely, SSL 2.0 ciphersuites in addition to the more common ones
from SSL 3.0/TLS 1.0.
So we change the selection algorithm again: Naming an explicit
ciphersuite selects this one ciphersuite, and any other similar
ciphersuite (same bitmap) from *other* protocol versions.
Thus, "RC4-MD5" again will properly select both the SSL 2.0
ciphersuite and the SSL 3.0/TLS 1.0 ciphersuite.
Since SSL 2.0 does not have any ciphersuites for which the
128/256 bit distinction would be relevant, this works for now.
The proper fix will be to use different bits for AES128 and
AES256, which would have avoided the problems from the beginning;
however, bits are scarce, so we can only do this in a new release
(not just a patchlevel) when we can change the SSL_CIPHER
definition to split the single 'unsigned long mask' bitmap into
multiple values to extend the available space.
[Bodo Moeller]
Changes between 0.9.8b and 0.9.8c [05 Sep 2006]
*) Avoid PKCS #1 v1.5 signature attack discovered by Daniel Bleichenbacher

28
ssl/ssl_ciph.c
View file

@ -565,7 +565,7 @@ static void ssl_cipher_collect_aliases(SSL_CIPHER **ca_list,
*ca_curr = NULL; /* end of list */
}
static void ssl_cipher_apply_rule(unsigned long cipher_id,
static void ssl_cipher_apply_rule(unsigned long cipher_id, unsigned long ssl_version,
unsigned long algorithms, unsigned long mask,
unsigned long algo_strength, unsigned long mask_strength,
int rule, int strength_bits, CIPHER_ORDER *co_list,
@ -592,9 +592,10 @@ static void ssl_cipher_apply_rule(unsigned long cipher_id,
cp = curr->cipher;
/* If explicit cipher suite match that one only */
/* If explicit cipher suite, match only that one for its own protocol version.
* Usual selection criteria will be used for similar ciphersuites from other version! */
if (cipher_id)
if (cipher_id && (cp->algorithms & SSL_SSL_MASK) == ssl_version)
{
if (cp->id != cipher_id)
continue;
@ -731,7 +732,7 @@ static int ssl_cipher_strength_sort(CIPHER_ORDER *co_list,
*/
for (i = max_strength_bits; i >= 0; i--)
if (number_uses[i] > 0)
ssl_cipher_apply_rule(0, 0, 0, 0, 0, CIPHER_ORD, i,
ssl_cipher_apply_rule(0, 0, 0, 0, 0, 0, CIPHER_ORD, i,
co_list, head_p, tail_p);
OPENSSL_free(number_uses);
@ -745,7 +746,7 @@ static int ssl_cipher_process_rulestr(const char *rule_str,
unsigned long algorithms, mask, algo_strength, mask_strength;
const char *l, *start, *buf;
int j, multi, found, rule, retval, ok, buflen;
unsigned long cipher_id = 0;
unsigned long cipher_id = 0, ssl_version = 0;
char ch;
retval = 1;
@ -836,6 +837,7 @@ static int ssl_cipher_process_rulestr(const char *rule_str,
*/
j = found = 0;
cipher_id = 0;
ssl_version = 0;
while (ca_list[j])
{
if (!strncmp(buf, ca_list[j]->name, buflen) &&
@ -850,12 +852,6 @@ static int ssl_cipher_process_rulestr(const char *rule_str,
if (!found)
break; /* ignore this entry */
if (ca_list[j]->valid)
{
cipher_id = ca_list[j]->id;
break;
}
/* New algorithms:
* 1 - any old restrictions apply outside new mask
* 2 - any new restrictions apply outside old mask
@ -870,6 +866,14 @@ static int ssl_cipher_process_rulestr(const char *rule_str,
(algo_strength & ca_list[j]->algo_strength);
mask_strength |= ca_list[j]->mask_strength;
/* explicit ciphersuite found */
if (ca_list[j]->valid)
{
cipher_id = ca_list[j]->id;
ssl_version = ca_list[j]->algorithms & SSL_SSL_MASK;
break;
}
if (!multi) break;
}
@ -899,7 +903,7 @@ static int ssl_cipher_process_rulestr(const char *rule_str,
}
else if (found)
{
ssl_cipher_apply_rule(cipher_id, algorithms, mask,
ssl_cipher_apply_rule(cipher_id, ssl_version, algorithms, mask,
algo_strength, mask_strength, rule, -1,
co_list, head_p, tail_p);
}