m_challenge: fix use of undefined behaviour.

GCC does what we expect, but other compilers could do just about anything.

diff --git a/modules/m_challenge.c b/modules/m_challenge.c
index 73f8e909aec33aa27776e43d284be9ee7b7fedfa..20660952066ad68f4ad79f7879126688831738ca 100644 (file)
--- a/modules/m_challenge.c
+++ b/modules/m_challenge.c
@@ -142,7 +142,8 @@ m_challenge(struct Client *client_p, struct Client *source_p, int parc, const ch
                        return 0;                       
                }
 
-               b_response = rb_base64_decode((const unsigned char *)++parv[1], strlen(parv[1]), &len);
+               parv[1]++;
+               b_response = rb_base64_decode((const unsigned char *)parv[1], strlen(parv[1]), &len);
 
                if(len != SHA_DIGEST_LENGTH ||
                   memcmp(source_p->localClient->challenge, b_response, SHA_DIGEST_LENGTH))