Messages in this thread Patch in this message | | | Subject | Re: An oops while running 2.5.65-mm2 | From | Martin Josefsson <> | Date | 22 Mar 2003 00:59:42 +0100 |
| |
On Fri, 2003-03-21 at 02:19, Martin Josefsson wrote:
> You are correct. It was a list_del() that caused it (at least I think > so, it's 2am right now). > > 1. conntrack helper adds an expectation and adds that to a list hanging > of off a connection. > > 2. the expected connection arrives. the expectation is still on the > list. > > 3. the original connection that caused the expectation terminates but > the expectation still thinks it's added to the list. > > 4. the expected connection terminates and list_del() is called to remove > it from the list which doesn't exist anymore. boom!
Ok, the previous patch was a little bit incorrect. It did fix the use after free bug (which can cause corruption if the slabmemory is reallocated before we write to it) but lost some internal information. I can't see that we use this anywhere after this point but here's the proper patch.
Sorry about that.
--- linux-2.5.64-bk10/net/ipv4/netfilter/ip_conntrack_core.c.orig 2003-03-21 01:42:57.000000000 +0100 +++ linux-2.5.64-bk10/net/ipv4/netfilter/ip_conntrack_core.c 2003-03-22 00:43:28.000000000 +0100 @@ -274,6 +274,7 @@ * the un-established ones only */ if (exp->sibling) { DEBUGP("remove_expectations: skipping established %p of %p\n", exp->sibling, ct); + exp->expectant = NULL; continue; } @@ -327,9 +328,11 @@ WRITE_LOCK(&ip_conntrack_lock); /* Delete our master expectation */ if (ct->master) { - /* can't call __unexpect_related here, - * since it would screw up expect_list */ - list_del(&ct->master->expected_list); + if (ct->master->expectant) { + /* can't call __unexpect_related here, + * since it would screw up expect_list */ + list_del(&ct->master->expected_list); + } kfree(ct->master); } WRITE_UNLOCK(&ip_conntrack_lock); -- /Martin Never argue with an idiot. They drag you down to their level, then beat you with experience. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |