ssl_cipher_process_rulestr: don't read outside rule_str buffer

If rule_str ended in a "-", "l" was incremented one byte past the
end of the buffer.  This resulted in an out-of-bounds read when "l"
is dereferenced at the end of the loop.  It is safest to just return
early in this case since the condition occurs inside a nested loop.

CLA: trivial

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19166)

(cherry picked from commit 428511ca66670e169a0e1b12e7540714b0be4cf8)

diff --git a/ssl/ssl_ciph.c b/ssl/ssl_ciph.c
index 55f919fcd58abfedaca03d9a7e564ec8b59d7a85..62d0a58b22dcd364b2bd4006f2675143e06c846d 100644 (file)
--- a/ssl/ssl_ciph.c
+++ b/ssl/ssl_ciph.c
@@ -1026,9 +1026,7 @@ static int ssl_cipher_process_rulestr(const char *rule_str,
                  * alphanumeric, so we call this an error.
                  */
                 SSLerr(SSL_F_SSL_CIPHER_PROCESS_RULESTR, SSL_R_INVALID_COMMAND);
-                retval = found = 0;
-                l++;
-                break;
+                return 0;
             }
 
             if (rule == CIPHER_SPECIAL) {