| Message ID | 20220701145423.53208-1-code@siddh.me |
|---|---|
| State | Superseded |
| Headers | show |
| Series | net: Fix UAF in ieee80211_scan_rx() | expand |
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 >
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
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
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()
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 > >
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
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
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)
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(-)