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| Started by | Colin King <colin.king@canonical.com> |
|---|---|
| First post | 2017-05-18 16:10 +0200 |
| Last post | 2017-05-20 09:20 +0200 |
| Articles | 4 — 4 participants |
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[PATCH] net: sched: fix a use-after-free error on chain on the error exit path Colin King <colin.king@canonical.com> - 2017-05-18 16:10 +0200
Re: [PATCH] net: sched: fix a use-after-free error on chain on the error exit path David Miller <davem@davemloft.net> - 2017-05-18 17:40 +0200
Re: [PATCH] net: sched: fix a use-after-free error on chain on the error exit path Cong Wang <xiyou.wangcong@gmail.com> - 2017-05-19 19:20 +0200
Re: [PATCH] net: sched: fix a use-after-free error on chain on the error exit path Jiri Pirko <jiri@resnulli.us> - 2017-05-20 09:20 +0200
| From | Colin King <colin.king@canonical.com> |
|---|---|
| Date | 2017-05-18 16:10 +0200 |
| Subject | [PATCH] net: sched: fix a use-after-free error on chain on the error exit path |
| Message-ID | <tIuhQ-3NF-11@gated-at.bofh.it> |
From: Colin Ian King <colin.king@canonical.com>
Set chain to null after the call to tcf_chain_destroy so that we don't
call tcf_chain_put on the error exit path, thus avoiding a use-after-free
error.
Detected by CoverityScan, CID#1436357 ("Use after free")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
net/sched/cls_api.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 4020b8d932a1..82ebdc3fcb2e 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -511,6 +511,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
tcf_chain_destroy(chain);
+ chain = NULL;
err = 0;
goto errout;
}
--
2.11.0
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| From | David Miller <davem@davemloft.net> |
|---|---|
| Date | 2017-05-18 17:40 +0200 |
| Subject | Re: [PATCH] net: sched: fix a use-after-free error on chain on the error exit path |
| Message-ID | <tIvGW-4Cy-9@gated-at.bofh.it> |
| In reply to | #1644580 |
From: Colin King <colin.king@canonical.com>
Date: Thu, 18 May 2017 15:07:02 +0100
> From: Colin Ian King <colin.king@canonical.com>
>
> Set chain to null after the call to tcf_chain_destroy so that we don't
> call tcf_chain_put on the error exit path, thus avoiding a use-after-free
> error.
>
> Detected by CoverityScan, CID#1436357 ("Use after free")
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
Colin, you really need to make some adjustments to how you are submitting
these kinds of patches.
First of all, you must indicate the target tree in your Subject line
as "[PATCH net-next] " in this case.
Also, you need to add an appropriate Fixes: tag right before your
signoff.
Thank you.
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| From | Cong Wang <xiyou.wangcong@gmail.com> |
|---|---|
| Date | 2017-05-19 19:20 +0200 |
| Subject | Re: [PATCH] net: sched: fix a use-after-free error on chain on the error exit path |
| Message-ID | <tITJf-5fr-3@gated-at.bofh.it> |
| In reply to | #1644580 |
On Thu, May 18, 2017 at 7:07 AM, Colin King <colin.king@canonical.com> wrote:
> diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
> index 4020b8d932a1..82ebdc3fcb2e 100644
> --- a/net/sched/cls_api.c
> +++ b/net/sched/cls_api.c
> @@ -511,6 +511,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
> if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
> tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
> tcf_chain_destroy(chain);
Jiri, how does this work...? An action could hold a refcnt to a filter
chain, but here you destroy a whole chain without respecting
the refcnt???
> + chain = NULL;
> err = 0;
> goto errout;
Colin, not your fault, I think we may miss something more serious
when reviewing Jiri's patchset. ;)
Thanks.
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| From | Jiri Pirko <jiri@resnulli.us> |
|---|---|
| Date | 2017-05-20 09:20 +0200 |
| Subject | Re: [PATCH] net: sched: fix a use-after-free error on chain on the error exit path |
| Message-ID | <tJ6Q9-6jt-5@gated-at.bofh.it> |
| In reply to | #1645778 |
Fri, May 19, 2017 at 07:17:59PM CEST, xiyou.wangcong@gmail.com wrote:
>On Thu, May 18, 2017 at 7:07 AM, Colin King <colin.king@canonical.com> wrote:
>> diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
>> index 4020b8d932a1..82ebdc3fcb2e 100644
>> --- a/net/sched/cls_api.c
>> +++ b/net/sched/cls_api.c
>> @@ -511,6 +511,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
>> if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
>> tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
>> tcf_chain_destroy(chain);
>
>
>Jiri, how does this work...? An action could hold a refcnt to a filter
>chain, but here you destroy a whole chain without respecting
>the refcnt???
Correct. I missed this. Will fix, thanks.
>
>
>> + chain = NULL;
>> err = 0;
>> goto errout;
>
>Colin, not your fault, I think we may miss something more serious
>when reviewing Jiri's patchset. ;)
>
>Thanks.
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