This is a note to let you know that I've just added the patch titled
net/sched: cls_api: fix error handling causing NULL dereference
to the 6.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-sched-cls_api-fix-error-handling-causing-null-de.patch
and it can be found in the queue-6.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8c05fb41896c01561c3ed88202f834a3e15b3f77
Author: Pierre Riteau <pierre@xxxxxxxxxxxx>
Date: Thu Feb 13 23:36:10 2025 +0100
net/sched: cls_api: fix error handling causing NULL dereference
[ Upstream commit 071ed42cff4fcdd89025d966d48eabef59913bf2 ]
tcf_exts_miss_cookie_base_alloc() calls xa_alloc_cyclic() which can
return 1 if the allocation succeeded after wrapping. This was treated as
an error, with value 1 returned to caller tcf_exts_init_ex() which sets
exts->actions to NULL and returns 1 to caller fl_change().
fl_change() treats err == 1 as success, calling tcf_exts_validate_ex()
which calls tcf_action_init() with exts->actions as argument, where it
is dereferenced.
Example trace:
BUG: kernel NULL pointer dereference, address: 0000000000000000
CPU: 114 PID: 16151 Comm: handler114 Kdump: loaded Not tainted 5.14.0-503.16.1.el9_5.x86_64 #1
RIP: 0010:tcf_action_init+0x1f8/0x2c0
Call Trace:
tcf_action_init+0x1f8/0x2c0
tcf_exts_validate_ex+0x175/0x190
fl_change+0x537/0x1120 [cls_flower]
Fixes: 80cd22c35c90 ("net/sched: cls_api: Support hardware miss to tc action")
Signed-off-by: Pierre Riteau <pierre@xxxxxxxxxxxx>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@xxxxxxxxxxxxxxx>
Link: https://patch.msgid.link/20250213223610.320278-1-pierre@xxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 8e47e5355be61..4f648af8cfaaf 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -97,7 +97,7 @@ tcf_exts_miss_cookie_base_alloc(struct tcf_exts *exts, struct tcf_proto *tp,
err = xa_alloc_cyclic(&tcf_exts_miss_cookies_xa, &n->miss_cookie_base,
n, xa_limit_32b, &next, GFP_KERNEL);
- if (err)
+ if (err < 0)
goto err_xa_alloc;
exts->miss_cookie_node = n;
