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- From 97fccc87f1297d189ee80735e5b8746c34956eda Mon Sep 17 00:00:00 2001
- From: Willy Tarreau <w@1wt.eu>
- Date: Wed, 13 May 2015 12:08:21 +0200
- Subject: [PATCH 7/8] BUG/MAJOR: checks: always check for end of list before
- proceeding
-
- This is the most important fix of this series. There's a risk of endless
- loop and crashes caused by the fact that we go past the head of the list
- when skipping to next rule, without checking if it's still a valid element.
- Most of the time, the ->action field is checked, which points to the proxy's
- check_req pointer (generally NULL), meaning the element is confused with a
- TCPCHK_ACT_SEND action.
-
- The situation was accidently made worse with the addition of tcp-check
- comment since it also skips list elements. However, since the action that
- makes it go forward is TCPCHK_ACT_COMMENT (3), there's little chance to
- see this as a valid pointer, except on 64-bit machines where it can match
- the end of a check_req string pointer.
-
- This fix heavily depends on previous cleanup and both must be backported
- to 1.5 where the bug is present.
- (cherry picked from commit f2c87353a7f8160930b5f342bb6d6ad0991ee3d1)
- [wt: this patch differs significantly from 1.6 since we don't have comments]
- ---
- src/cfgparse.c | 4 +++-
- src/checks.c | 12 ++++++++++++
- 2 files changed, 15 insertions(+), 1 deletion(-)
-
- diff --git a/src/cfgparse.c b/src/cfgparse.c
- index 746c7eb..dba59d1 100644
- --- a/src/cfgparse.c
- +++ b/src/cfgparse.c
- @@ -4368,7 +4368,9 @@ stats_error_parsing:
- l = (struct list *)&curproxy->tcpcheck_rules;
- if (l->p != l->n) {
- tcpcheck = (struct tcpcheck_rule *)l->n;
- - if (tcpcheck && tcpcheck->action != TCPCHK_ACT_CONNECT) {
- +
- + if (&tcpcheck->list != &curproxy->tcpcheck_rules
- + && tcpcheck->action != TCPCHK_ACT_CONNECT) {
- Alert("parsing [%s:%d] : first step MUST also be a 'connect' when there is a 'connect' step in the tcp-check ruleset.\n",
- file, linenum);
- err_code |= ERR_ALERT | ERR_FATAL;
- diff --git a/src/checks.c b/src/checks.c
- index a0c42f2..e13d561 100644
- --- a/src/checks.c
- +++ b/src/checks.c
- @@ -2057,6 +2057,9 @@ static void tcpcheck_main(struct connection *conn)
- /* allow next rule */
- check->current_step = (struct tcpcheck_rule *)check->current_step->list.n;
-
- + if (&check->current_step->list == head)
- + break;
- +
- /* don't do anything until the connection is established */
- if (!(conn->flags & CO_FL_CONNECTED)) {
- /* update expire time, should be done by process_chk */
- @@ -2110,6 +2113,9 @@ static void tcpcheck_main(struct connection *conn)
-
- /* go to next rule and try to send */
- check->current_step = (struct tcpcheck_rule *)check->current_step->list.n;
- +
- + if (&check->current_step->list == head)
- + break;
- } /* end 'send' */
- else if (check->current_step->action == TCPCHK_ACT_EXPECT) {
- if (unlikely(check->result == CHK_RES_FAILED))
- @@ -2196,6 +2202,9 @@ static void tcpcheck_main(struct connection *conn)
- /* allow next rule */
- check->current_step = (struct tcpcheck_rule *)check->current_step->list.n;
-
- + if (&check->current_step->list == head)
- + break;
- +
- if (check->current_step->action == TCPCHK_ACT_EXPECT)
- goto tcpcheck_expect;
- __conn_data_stop_recv(conn);
- @@ -2208,6 +2217,9 @@ static void tcpcheck_main(struct connection *conn)
- /* allow next rule */
- check->current_step = (struct tcpcheck_rule *)check->current_step->list.n;
-
- + if (&check->current_step->list == head)
- + break;
- +
- if (check->current_step->action == TCPCHK_ACT_EXPECT)
- goto tcpcheck_expect;
- __conn_data_stop_recv(conn);
- --
- 2.0.5
-
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