* [PATCH net] net/sched: Fix memory leak in tcindex_set_parms
@ 2022-12-08 3:22 Chen Zhongjin
2022-12-08 6:35 ` Chen Zhongjin
2022-12-08 11:06 ` [syzbot] memory leak in tcindex_set_parms (3) syzbot
0 siblings, 2 replies; 3+ messages in thread
From: Chen Zhongjin @ 2022-12-08 3:22 UTC (permalink / raw)
To: syzbot+2f9183cb6f89b0e16586, syzkaller-bugs, netdev, stable,
linux-kernel
Cc: chenzhongjin, jhs, xiyou.wangcong, jiri, davem, edumazet, kuba,
pabeni, gregkh
syzkaller reported a memleak:
https://syzkaller.appspot.com/bug?id=e061e6cd46417ee6566dc249d8f982c0b5977a52
unreferenced object 0xffff888107813900 (size 256):
backtrace:
kcalloc include/linux/slab.h:636 [inline]
tcf_exts_init include/net/pkt_cls.h:250 [inline]
tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342
tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553
tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147
...
The reproduce calls tc_new_tfilter() continuously:
tc_new_tfilter()...
tcindex_set_parms()
tcf_exts_init(&e, ...) // alloc e->actions
tcf_exts_change(&r->exts, &e)
tc_new_tfilter()...
tcindex_set_parms()
old_r = r // same as first r
tcindex_filter_result_init(old_r, cp, net);
// old_r is holding e->actions but here it calls memset(old_r, 0)
// so the previous e->actions is leaked
So here tcf_exts_destroy() should be called to free old_r->exts.actions
before memset(old_r, 0) sets it to NULL.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Reported-by: syzbot+2f9183cb6f89b0e16586@syzkaller.appspotmail.com
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 355479c70a48
---
net/sched/cls_tcindex.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index 1c9eeb98d826..00a6c04a4b42 100644
--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -479,6 +479,7 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
}
if (old_r && old_r != r) {
+ tcf_exts_destroy(&old_r->exts);
err = tcindex_filter_result_init(old_r, cp, net);
if (err < 0) {
kfree(f);
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net] net/sched: Fix memory leak in tcindex_set_parms
2022-12-08 3:22 [PATCH net] net/sched: Fix memory leak in tcindex_set_parms Chen Zhongjin
@ 2022-12-08 6:35 ` Chen Zhongjin
2022-12-08 11:06 ` [syzbot] memory leak in tcindex_set_parms (3) syzbot
1 sibling, 0 replies; 3+ messages in thread
From: Chen Zhongjin @ 2022-12-08 6:35 UTC (permalink / raw)
To: syzbot+2f9183cb6f89b0e16586, syzkaller-bugs, netdev, stable,
linux-kernel
Cc: jhs, xiyou.wangcong, jiri, davem, edumazet, kuba, pabeni, gregkh
Hi,
On 2022/12/8 11:22, Chen Zhongjin wrote:
> syzkaller reported a memleak:
> https://syzkaller.appspot.com/bug?id=e061e6cd46417ee6566dc249d8f982c0b5977a52
>
> unreferenced object 0xffff888107813900 (size 256):
> backtrace:
> kcalloc include/linux/slab.h:636 [inline]
> tcf_exts_init include/net/pkt_cls.h:250 [inline]
> tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342
> tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553
> tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147
> ...
>
> The reproduce calls tc_new_tfilter() continuously:
>
> tc_new_tfilter()...
> tcindex_set_parms()
> tcf_exts_init(&e, ...) // alloc e->actions
> tcf_exts_change(&r->exts, &e)
>
> tc_new_tfilter()...
> tcindex_set_parms()
> old_r = r // same as first r
> tcindex_filter_result_init(old_r, cp, net);
> // old_r is holding e->actions but here it calls memset(old_r, 0)
> // so the previous e->actions is leaked
>
> So here tcf_exts_destroy() should be called to free old_r->exts.actions
> before memset(old_r, 0) sets it to NULL.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Cc: stable@vger.kernel.org
> Reported-by: syzbot+2f9183cb6f89b0e16586@syzkaller.appspotmail.com
> Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
> ---
> #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 355479c70a48
> ---
> net/sched/cls_tcindex.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
> index 1c9eeb98d826..00a6c04a4b42 100644
> --- a/net/sched/cls_tcindex.c
> +++ b/net/sched/cls_tcindex.c
> @@ -479,6 +479,7 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
> }
>
> if (old_r && old_r != r) {
> + tcf_exts_destroy(&old_r->exts);
> err = tcindex_filter_result_init(old_r, cp, net);
> if (err < 0) {
> kfree(f);
Just noticed that Hawkins has sent a patch for this. Please ignore mine.
Thanks!
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [syzbot] memory leak in tcindex_set_parms (3)
2022-12-08 3:22 [PATCH net] net/sched: Fix memory leak in tcindex_set_parms Chen Zhongjin
2022-12-08 6:35 ` Chen Zhongjin
@ 2022-12-08 11:06 ` syzbot
1 sibling, 0 replies; 3+ messages in thread
From: syzbot @ 2022-12-08 11:06 UTC (permalink / raw)
To: chenzhongjin, davem, edumazet, gregkh, jhs, jiri, kuba,
linux-kernel, netdev, pabeni, stable, syzkaller-bugs,
xiyou.wangcong
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-and-tested-by: syzbot+2f9183cb6f89b0e16586@syzkaller.appspotmail.com
Tested on:
commit: 355479c7 Merge tag 'efi-fixes-for-v6.1-4' of git://git..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=175b5b23880000
kernel config: https://syzkaller.appspot.com/x/.config?x=979161df0e247659
dashboard link: https://syzkaller.appspot.com/bug?extid=2f9183cb6f89b0e16586
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=142313f3880000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-12-08 3:22 [PATCH net] net/sched: Fix memory leak in tcindex_set_parms Chen Zhongjin
2022-12-08 6:35 ` Chen Zhongjin
2022-12-08 11:06 ` [syzbot] memory leak in tcindex_set_parms (3) syzbot
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