* [PATCH] net: Fix UAF in ieee80211_scan_rx()
@ 2022-07-01 14:54 Siddh Raman Pant
2022-07-07 11:36 ` Ping: " Siddh Raman Pant via Linux-kernel-mentees
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Siddh Raman Pant @ 2022-07-01 14:54 UTC (permalink / raw)
To: Johannes Berg, David S . Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni
Cc: netdev, linux-wireless, linux-kernel, linux-kernel-mentees
ieee80211_scan_rx() tries to access scan_req->flags after a null check
(see line 303 of mac80211/scan.c), but ___cfg80211_scan_done() uses
kfree() on the scan_req (see line 991 of wireless/scan.c).
This results in a UAF.
ieee80211_scan_rx() is called inside a RCU read-critical section
initiated by ieee80211_rx_napi() (see line 5043 of mac80211/rx.c).
Thus, add an rcu_head to the scan_req struct so as to use kfree_rcu()
instead of kfree() so that we don't free during the critical section.
Bug report (3): https://syzkaller.appspot.com/bug?extid=f9acff9bf08a845f225d
Reported-by: syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com
Reported-by: syzbot+6cb476b7c69916a0caca@syzkaller.appspotmail.com
Reported-by: syzbot+9250865a55539d384347@syzkaller.appspotmail.com
Signed-off-by: Siddh Raman Pant <code@siddh.me>
---
include/net/cfg80211.h | 2 ++
net/wireless/scan.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 6d02e12e4702..ba4a49884de8 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2368,6 +2368,7 @@ struct cfg80211_scan_6ghz_params {
* @n_6ghz_params: number of 6 GHz params
* @scan_6ghz_params: 6 GHz params
* @bssid: BSSID to scan for (most commonly, the wildcard BSSID)
+ * @rcu_head: (internal) RCU head to use for freeing
*/
struct cfg80211_scan_request {
struct cfg80211_ssid *ssids;
@@ -2397,6 +2398,7 @@ struct cfg80211_scan_request {
bool scan_6ghz;
u32 n_6ghz_params;
struct cfg80211_scan_6ghz_params *scan_6ghz_params;
+ struct rcu_head rcu_head;
/* keep last */
struct ieee80211_channel *channels[];
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 6d82bd9eaf8c..638b2805222c 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -988,7 +988,7 @@ void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev,
kfree(rdev->int_scan_req);
rdev->int_scan_req = NULL;
- kfree(rdev->scan_req);
+ kfree_rcu(rdev->scan_req, rcu_head);
rdev->scan_req = NULL;
if (!send_message)
--
2.35.1
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^ permalink raw reply related [flat|nested] 8+ messages in thread
* Ping: [PATCH] net: Fix UAF in ieee80211_scan_rx()
2022-07-01 14:54 [PATCH] net: Fix UAF in ieee80211_scan_rx() Siddh Raman Pant
@ 2022-07-07 11:36 ` Siddh Raman Pant via Linux-kernel-mentees
2022-07-07 11:50 ` Greg KH
2022-07-26 9:55 ` Kalle Valo
2022-07-26 10:07 ` Eric Dumazet via Linux-kernel-mentees
2 siblings, 1 reply; 8+ messages in thread
From: Siddh Raman Pant via Linux-kernel-mentees @ 2022-07-07 11:36 UTC (permalink / raw)
To: Johannes Berg, David S . Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni
Cc: netdev, linux-wireless, linux-kernel, linux-kernel-mentees
Ping?
On Fri, 01 Jul 2022 20:24:23 +0530 Siddh Raman Pant <code@siddh.me> wrote
> ieee80211_scan_rx() tries to access scan_req->flags after a null check
> (see line 303 of mac80211/scan.c), but ___cfg80211_scan_done() uses
> kfree() on the scan_req (see line 991 of wireless/scan.c).
>
> This results in a UAF.
>
> ieee80211_scan_rx() is called inside a RCU read-critical section
> initiated by ieee80211_rx_napi() (see line 5043 of mac80211/rx.c).
>
> Thus, add an rcu_head to the scan_req struct so as to use kfree_rcu()
> instead of kfree() so that we don't free during the critical section.
>
> Bug report (3): https://syzkaller.appspot.com/bug?extid=f9acff9bf08a845f225d
> Reported-by: syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com
> Reported-by: syzbot+6cb476b7c69916a0caca@syzkaller.appspotmail.com
> Reported-by: syzbot+9250865a55539d384347@syzkaller.appspotmail.com
>
> Signed-off-by: Siddh Raman Pant <code@siddh.me>
> ---
> include/net/cfg80211.h | 2 ++
> net/wireless/scan.c | 2 +-
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index 6d02e12e4702..ba4a49884de8 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -2368,6 +2368,7 @@ struct cfg80211_scan_6ghz_params {
> * @n_6ghz_params: number of 6 GHz params
> * @scan_6ghz_params: 6 GHz params
> * @bssid: BSSID to scan for (most commonly, the wildcard BSSID)
> + * @rcu_head: (internal) RCU head to use for freeing
> */
> struct cfg80211_scan_request {
> struct cfg80211_ssid *ssids;
> @@ -2397,6 +2398,7 @@ struct cfg80211_scan_request {
> bool scan_6ghz;
> u32 n_6ghz_params;
> struct cfg80211_scan_6ghz_params *scan_6ghz_params;
> + struct rcu_head rcu_head;
>
> /* keep last */
> struct ieee80211_channel *channels[];
> diff --git a/net/wireless/scan.c b/net/wireless/scan.c
> index 6d82bd9eaf8c..638b2805222c 100644
> --- a/net/wireless/scan.c
> +++ b/net/wireless/scan.c
> @@ -988,7 +988,7 @@ void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev,
> kfree(rdev->int_scan_req);
> rdev->int_scan_req = NULL;
>
> - kfree(rdev->scan_req);
> + kfree_rcu(rdev->scan_req, rcu_head);
> rdev->scan_req = NULL;
>
> if (!send_message)
> --
> 2.35.1
>
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Ping: [PATCH] net: Fix UAF in ieee80211_scan_rx()
2022-07-07 11:36 ` Ping: " Siddh Raman Pant via Linux-kernel-mentees
@ 2022-07-07 11:50 ` Greg KH
2022-07-07 11:59 ` Siddh Raman Pant via Linux-kernel-mentees
0 siblings, 1 reply; 8+ messages in thread
From: Greg KH @ 2022-07-07 11:50 UTC (permalink / raw)
To: Siddh Raman Pant
Cc: netdev, linux-wireless, linux-kernel, Eric Dumazet,
Jakub Kicinski, Johannes Berg, Paolo Abeni, linux-kernel-mentees,
David S . Miller
On Thu, Jul 07, 2022 at 05:06:35PM +0530, Siddh Raman Pant via Linux-kernel-mentees wrote:
> Ping?
context-less pings, on a patch that was sent less than 1 week ago, are
usually not a good idea. Normally wait for 2 weeks and then resend if
you have not heard anything back.
good luck!
greg k-h
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Ping: [PATCH] net: Fix UAF in ieee80211_scan_rx()
2022-07-07 11:50 ` Greg KH
@ 2022-07-07 11:59 ` Siddh Raman Pant via Linux-kernel-mentees
0 siblings, 0 replies; 8+ messages in thread
From: Siddh Raman Pant via Linux-kernel-mentees @ 2022-07-07 11:59 UTC (permalink / raw)
To: Greg KH
Cc: netdev, linux-wireless, linux-kernel, Eric Dumazet,
Jakub Kicinski, Johannes Berg, Paolo Abeni, linux-kernel-mentees,
David S . Miller
On Thu, 07 Jul 2022 17:20:56 +0530 Greg KH <gregkh@linuxfoundation.org> wrote
> On Thu, Jul 07, 2022 at 05:06:35PM +0530, Siddh Raman Pant via Linux-kernel-mentees wrote:
> > Ping?
>
> context-less pings, on a patch that was sent less than 1 week ago, are
> usually not a good idea. Normally wait for 2 weeks and then resend if
> you have not heard anything back.
>
> good luck!
>
> greg k-h
Sorry, I never intended to disturb anyone.
Thanks for informing,
Siddh
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] net: Fix UAF in ieee80211_scan_rx()
2022-07-01 14:54 [PATCH] net: Fix UAF in ieee80211_scan_rx() Siddh Raman Pant
2022-07-07 11:36 ` Ping: " Siddh Raman Pant via Linux-kernel-mentees
@ 2022-07-26 9:55 ` Kalle Valo
2022-07-26 11:50 ` Siddh Raman Pant via Linux-kernel-mentees
2022-07-26 10:07 ` Eric Dumazet via Linux-kernel-mentees
2 siblings, 1 reply; 8+ messages in thread
From: Kalle Valo @ 2022-07-26 9:55 UTC (permalink / raw)
To: Siddh Raman Pant
Cc: netdev, linux-wireless, linux-kernel, Eric Dumazet,
Jakub Kicinski, Johannes Berg, Paolo Abeni, linux-kernel-mentees,
David S . Miller
Siddh Raman Pant <code@siddh.me> writes:
> ieee80211_scan_rx() tries to access scan_req->flags after a null check
> (see line 303 of mac80211/scan.c), but ___cfg80211_scan_done() uses
> kfree() on the scan_req (see line 991 of wireless/scan.c).
>
> This results in a UAF.
>
> ieee80211_scan_rx() is called inside a RCU read-critical section
> initiated by ieee80211_rx_napi() (see line 5043 of mac80211/rx.c).
>
> Thus, add an rcu_head to the scan_req struct so as to use kfree_rcu()
> instead of kfree() so that we don't free during the critical section.
>
> Bug report (3): https://syzkaller.appspot.com/bug?extid=f9acff9bf08a845f225d
> Reported-by: syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com
> Reported-by: syzbot+6cb476b7c69916a0caca@syzkaller.appspotmail.com
> Reported-by: syzbot+9250865a55539d384347@syzkaller.appspotmail.com
>
> Signed-off-by: Siddh Raman Pant <code@siddh.me>
> ---
> include/net/cfg80211.h | 2 ++
> net/wireless/scan.c | 2 +-
> 2 files changed, 3 insertions(+), 1 deletion(-)
The title should be:
wifi: cfg80211: Fix UAF in ieee80211_scan_rx()
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] net: Fix UAF in ieee80211_scan_rx()
2022-07-01 14:54 [PATCH] net: Fix UAF in ieee80211_scan_rx() Siddh Raman Pant
2022-07-07 11:36 ` Ping: " Siddh Raman Pant via Linux-kernel-mentees
2022-07-26 9:55 ` Kalle Valo
@ 2022-07-26 10:07 ` Eric Dumazet via Linux-kernel-mentees
2022-07-26 12:16 ` Siddh Raman Pant via Linux-kernel-mentees
2 siblings, 1 reply; 8+ messages in thread
From: Eric Dumazet via Linux-kernel-mentees @ 2022-07-26 10:07 UTC (permalink / raw)
To: Siddh Raman Pant
Cc: Paul E. McKenney, netdev, linux-wireless, linux-kernel,
Jakub Kicinski, Johannes Berg, Paolo Abeni, linux-kernel-mentees,
David S . Miller
On Fri, Jul 1, 2022 at 4:55 PM Siddh Raman Pant <code@siddh.me> wrote:
>
> ieee80211_scan_rx() tries to access scan_req->flags after a null check
> (see line 303 of mac80211/scan.c), but ___cfg80211_scan_done() uses
> kfree() on the scan_req (see line 991 of wireless/scan.c).
>
> This results in a UAF.
>
> ieee80211_scan_rx() is called inside a RCU read-critical section
> initiated by ieee80211_rx_napi() (see line 5043 of mac80211/rx.c).
>
> Thus, add an rcu_head to the scan_req struct so as to use kfree_rcu()
> instead of kfree() so that we don't free during the critical section.
>
> Bug report (3): https://syzkaller.appspot.com/bug?extid=f9acff9bf08a845f225d
> Reported-by: syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com
> Reported-by: syzbot+6cb476b7c69916a0caca@syzkaller.appspotmail.com
> Reported-by: syzbot+9250865a55539d384347@syzkaller.appspotmail.com
>
> Signed-off-by: Siddh Raman Pant <code@siddh.me>
> ---
> include/net/cfg80211.h | 2 ++
> net/wireless/scan.c | 2 +-
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index 6d02e12e4702..ba4a49884de8 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -2368,6 +2368,7 @@ struct cfg80211_scan_6ghz_params {
> * @n_6ghz_params: number of 6 GHz params
> * @scan_6ghz_params: 6 GHz params
> * @bssid: BSSID to scan for (most commonly, the wildcard BSSID)
> + * @rcu_head: (internal) RCU head to use for freeing
> */
> struct cfg80211_scan_request {
> struct cfg80211_ssid *ssids;
> @@ -2397,6 +2398,7 @@ struct cfg80211_scan_request {
> bool scan_6ghz;
> u32 n_6ghz_params;
> struct cfg80211_scan_6ghz_params *scan_6ghz_params;
> + struct rcu_head rcu_head;
>
> /* keep last */
> struct ieee80211_channel *channels[];
> diff --git a/net/wireless/scan.c b/net/wireless/scan.c
> index 6d82bd9eaf8c..638b2805222c 100644
> --- a/net/wireless/scan.c
> +++ b/net/wireless/scan.c
> @@ -988,7 +988,7 @@ void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev,
> kfree(rdev->int_scan_req);
> rdev->int_scan_req = NULL;
>
> - kfree(rdev->scan_req);
> + kfree_rcu(rdev->scan_req, rcu_head);
> rdev->scan_req = NULL;
Note: this is slightly racy.
You are supposed to follow this order in this situation.
1) Clear the pointer
Then:
2) wait an rcu grace period (synchronize_rcu()) or use call_rcu()/kfree_rcu().
>
> if (!send_message)
> --
> 2.35.1
>
>
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] net: Fix UAF in ieee80211_scan_rx()
2022-07-26 9:55 ` Kalle Valo
@ 2022-07-26 11:50 ` Siddh Raman Pant via Linux-kernel-mentees
0 siblings, 0 replies; 8+ messages in thread
From: Siddh Raman Pant via Linux-kernel-mentees @ 2022-07-26 11:50 UTC (permalink / raw)
To: Kalle Valo
Cc: netdev, linux-wireless, linux-kernel, Eric Dumazet,
Jakub Kicinski, Johannes Berg, Paolo Abeni, linux-kernel-mentees,
David S . Miller
On Tue, 26 Jul 2022 15:25:06 +0530 Kalle Valo <kvalo@kernel.org> wrote ---
> The title should be:
>
> wifi: cfg80211: Fix UAF in ieee80211_scan_rx()
>
> --
> https://patchwork.kernel.org/project/linux-wireless/list/
>
> https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
>
Noted. Will fix.
Thanks,
Siddh
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] net: Fix UAF in ieee80211_scan_rx()
2022-07-26 10:07 ` Eric Dumazet via Linux-kernel-mentees
@ 2022-07-26 12:16 ` Siddh Raman Pant via Linux-kernel-mentees
0 siblings, 0 replies; 8+ messages in thread
From: Siddh Raman Pant via Linux-kernel-mentees @ 2022-07-26 12:16 UTC (permalink / raw)
To: Eric Dumazet
Cc: Paul E. McKenney, netdev, linux-wireless, linux-kernel,
Jakub Kicinski, Johannes Berg, Paolo Abeni, linux-kernel-mentees,
David S . Miller
On Tue, 26 Jul 2022 15:37:16 +0530 Eric Dumazet <edumazet@google.com> wrote:
> Note: this is slightly racy.
>
> You are supposed to follow this order in this situation.
>
> 1) Clear the pointer
>
> Then:
>
> 2) wait an rcu grace period (synchronize_rcu()) or use call_rcu()/kfree_rcu().
>
Noted. Due to rcu_dereference() used to get scan_req, null ptr dereference
cannot happen. That had completely missed my eyes, sorry for that.
I will send a v2.
Thanks,
Siddh
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^ permalink raw reply [flat|nested] 8+ messages in thread
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2022-07-01 14:54 [PATCH] net: Fix UAF in ieee80211_scan_rx() Siddh Raman Pant
2022-07-07 11:36 ` Ping: " Siddh Raman Pant via Linux-kernel-mentees
2022-07-07 11:50 ` Greg KH
2022-07-07 11:59 ` Siddh Raman Pant via Linux-kernel-mentees
2022-07-26 9:55 ` Kalle Valo
2022-07-26 11:50 ` Siddh Raman Pant via Linux-kernel-mentees
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