tree ef30d9bc768505beccd3b781e355dd73d8df984f
parent 4f889006269e4d3f802de46f280ed198a15e3a69
author Willy Tarreau <w@1wt.eu> 1431509897 +0200
committer Willy Tarreau <w@1wt.eu> 1431524984 +0200
encoding latin1

BUG/MEDIUM: checks: do not dereference head of a tcp-check at the end

When the end of the list is reached, the current step's action is checked
to know if we must poll or not. Unfortunately, the main reason for going
there is that we walked past the end of list and current_step points to
the head. We cannot dereference ->action since it does not belong to this
structure and can definitely crash if the address is not mapped.

This bug is unlikely to cause a crash since the action appears just after
the list, and corresponds to the "char *check_req" pointer in the proxy
struct, and it seems that we can't go there with current_step being null.
At worst it can cause the check to register for recv events.

This fix needs to be backported to 1.5 since the code is incorrect there
as well.
(cherry picked from commit 53c5a049e1f4dbf67412472e23690dc6b3c8d0f8)