BUG/MINOR: stick-table: Never exceed (MAX_SESS_STKCTR-1) when fetching a stkctr

When a stick counter is fetched, it is important that the requested counter does
not exceed (MAX_SESS_STKCTR -1). Actually, there is no bug with a default build
because, by construction, MAX_SESS_STKCTR is defined to 3 and we know that we
never exceed the max value. scN_* sample fetches are numbered from 0 to 2. For
other sample fetches, the value is tested.

But there is a bug if MAX_SESS_STKCTR is set to a lower value. For instance
1. In this case the counters sc1_* and sc2_* may be undefined.

This patch fixes the issue #330. It must be backported as far as 1.7.

diff --git a/src/stick_table.c b/src/stick_table.c
index 3429d047cdaf4d9873ae6064e15cb326020e2c71..86ea3ceea5c1c97a4bd9663d2b4f0aa1cc9d535d 100644 (file)
--- a/src/stick_table.c
+++ b/src/stick_table.c
@@ -2148,8 +2148,6 @@ smp_fetch_sc_stkctr(struct session *sess, struct stream *strm, const struct arg
        if (num == '_' - '0') {
                /* sc_* variant, args[0] = ctr# (mandatory) */
                num = args[arg++].data.sint;
-               if (num >= MAX_SESS_STKCTR)
-                       return NULL;
        }
        else if (num > 9) { /* src_* variant, args[0] = table */
                struct stktable_key *key;
@@ -2180,7 +2178,10 @@ smp_fetch_sc_stkctr(struct session *sess, struct stream *strm, const struct arg
         * the sc[0-9]_ form, or even higher using sc_(num) if needed.
         * args[arg] is the first optional argument. We first lookup the
         * ctr form the stream, then from the session if it was not there.
+        * But we must be sure the counter does not exceed MAX_SESS_STKCTR.
         */
+       if (num >= MAX_SESS_STKCTR)
+               return NULL;
 
        if (strm)
                stkptr = &strm->stkctr[num];