Date: Fri, 25 Feb 2005 15:00:44 +0100 (CET) From: Antoine Brodin <antoine.brodin@laposte.net> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/78070: [patch] Potential null pointer dereference in bge(4) Message-ID: <200502251400.j1PE0iQb018983@barton.dreadbsd.org> Resent-Message-ID: <200502251410.j1PEAG2i075264@freefall.freebsd.org>
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>Number: 78070
>Category: kern
>Synopsis: [patch] Potential null pointer dereference in bge(4)
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Feb 25 14:10:16 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator: Antoine Brodin
>Release: FreeBSD 6.0-CURRENT i386
>Organization:
none
>Environment:
System: FreeBSD barton.dreadbsd.org 6.0-CURRENT FreeBSD 6.0-CURRENT #0: Thu Feb 24 14:18:22 CET 2005 antoine@barton.dreadbsd.org:/usr/obj/usr/src/sys/BARTON i386
>Description:
If malloc(9) fails line 770 of if_bge.c, the free jumbo list will have
less than BGE_JSLOTS entries. bge_free_jumbo_mem() will be called and
it will try to remove and to free BGE_JSLOTS entries. This will cause
a null pointer dereference in SLIST_REMOVE_HEAD(3) if the list is
already empty.
>How-To-Repeat:
I don't have any bge(4) NIC and I haven't find any report of this
problem. It's probably because the jumbo buffer block allocation
will fail before the entries allocation if we're low on memory.
>Fix:
Patch attached:
--- if_bge.diff begins here ---
Index: dev/bge/if_bge.c
===================================================================
RCS file: /home/ncvs/src/sys/dev/bge/if_bge.c,v
retrieving revision 1.83
diff -u -p -r1.83 if_bge.c
--- dev/bge/if_bge.c 6 Jan 2005 01:42:30 -0000 1.83
+++ dev/bge/if_bge.c 25 Feb 2005 12:01:38 -0000
@@ -788,10 +788,9 @@ static void
bge_free_jumbo_mem(sc)
struct bge_softc *sc;
{
- int i;
struct bge_jpool_entry *entry;
- for (i = 0; i < BGE_JSLOTS; i++) {
+ while (!SLIST_EMPTY(&sc->bge_jfree_listhead)) {
entry = SLIST_FIRST(&sc->bge_jfree_listhead);
SLIST_REMOVE_HEAD(&sc->bge_jfree_listhead, jpool_entries);
free(entry, M_DEVBUF);
--- if_bge.diff ends here ---
>Release-Note:
>Audit-Trail:
>Unformatted:
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