* [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() @ 2020-09-10 4:34 Anmol Karn 2020-09-10 5:06 ` Eric Biggers 2020-09-10 10:49 ` Dan Carpenter 0 siblings, 2 replies; 12+ messages in thread From: Anmol Karn @ 2020-09-10 4:34 UTC (permalink / raw) To: marcel, johan.hedberg Cc: netdev, syzbot+0bef568258653cff272f, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem Prevent hci_phy_link_complete_evt() from dereferencing 'hcon->amp_mgr' as NULL. Fix it by adding pointer check for it. Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> --- net/bluetooth/hci_event.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 4b7fc430793c..871e16804433 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, return; } + if (IS_ERR_OR_NULL(hcon->amp_mgr)) { + hci_dev_unlock(hdev); + return; + } + if (ev->status) { hci_conn_del(hcon); hci_dev_unlock(hdev); -- 2.28.0 _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-10 4:34 [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() Anmol Karn @ 2020-09-10 5:06 ` Eric Biggers 2020-09-10 6:02 ` Anmol Karn 2020-09-10 10:49 ` Dan Carpenter 1 sibling, 1 reply; 12+ messages in thread From: Eric Biggers @ 2020-09-10 5:06 UTC (permalink / raw) To: Anmol Karn Cc: syzbot+0bef568258653cff272f, johan.hedberg, netdev, marcel, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem On Thu, Sep 10, 2020 at 10:04:24AM +0530, Anmol Karn wrote: > Prevent hci_phy_link_complete_evt() from dereferencing 'hcon->amp_mgr' > as NULL. Fix it by adding pointer check for it. > > Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f > Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> > --- > net/bluetooth/hci_event.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > index 4b7fc430793c..871e16804433 100644 > --- a/net/bluetooth/hci_event.c > +++ b/net/bluetooth/hci_event.c > @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > return; > } > > + if (IS_ERR_OR_NULL(hcon->amp_mgr)) { > + hci_dev_unlock(hdev); > + return; > + } > + In patches that fix a NULL pointer dereference, please include a brief explanation of why the pointer can be NULL, including what it means semantically; and why the proposed change is the best fix for the problem. Also, why IS_ERR_OR_NULL()? - Eric _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-10 5:06 ` Eric Biggers @ 2020-09-10 6:02 ` Anmol Karn 0 siblings, 0 replies; 12+ messages in thread From: Anmol Karn @ 2020-09-10 6:02 UTC (permalink / raw) To: Eric Biggers Cc: syzbot+0bef568258653cff272f, johan.hedberg, netdev, marcel, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem On Wed, Sep 09, 2020 at 10:06:59PM -0700, Eric Biggers wrote: > On Thu, Sep 10, 2020 at 10:04:24AM +0530, Anmol Karn wrote: > > Prevent hci_phy_link_complete_evt() from dereferencing 'hcon->amp_mgr' > > as NULL. Fix it by adding pointer check for it. > > > > Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com > > Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f > > Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> > > --- > > net/bluetooth/hci_event.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > > index 4b7fc430793c..871e16804433 100644 > > --- a/net/bluetooth/hci_event.c > > +++ b/net/bluetooth/hci_event.c > > @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > > return; > > } > > > > + if (IS_ERR_OR_NULL(hcon->amp_mgr)) { > > + hci_dev_unlock(hdev); > > + return; > > + } > > + > Hello Sir, > In patches that fix a NULL pointer dereference, please include a brief > explanation of why the pointer can be NULL, including what it means > semantically; and why the proposed change is the best fix for the problem. > I will surely add more explaination in v2. > Also, why IS_ERR_OR_NULL()? > I used IS_ERR_OR_NULL() to check if the 'hcon->amp_mgr' is a valid pointer or not, and unregister the 'hcon' and signal error, but will make changes in v2 with only NULL check included, if you think it's incorrect to use IS_ERR check here along with NULL. Thanks, Anmol Karn _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-10 4:34 [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() Anmol Karn 2020-09-10 5:06 ` Eric Biggers @ 2020-09-10 10:49 ` Dan Carpenter 2020-09-10 14:58 ` Anmol Karn 2020-09-12 9:10 ` Anmol Karn 1 sibling, 2 replies; 12+ messages in thread From: Dan Carpenter @ 2020-09-10 10:49 UTC (permalink / raw) To: Anmol Karn Cc: syzbot+0bef568258653cff272f, johan.hedberg, netdev, marcel, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem On Thu, Sep 10, 2020 at 10:04:24AM +0530, Anmol Karn wrote: > Prevent hci_phy_link_complete_evt() from dereferencing 'hcon->amp_mgr' > as NULL. Fix it by adding pointer check for it. > > Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f > Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> > --- > net/bluetooth/hci_event.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > index 4b7fc430793c..871e16804433 100644 > --- a/net/bluetooth/hci_event.c > +++ b/net/bluetooth/hci_event.c > @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > return; > } > > + if (IS_ERR_OR_NULL(hcon->amp_mgr)) { It can't be an error pointer. Shouldn't we call hci_conn_del() on this path? Try to find the Fixes tag to explain how this bug was introduced. (Don't rush to send a v2. The patch requires quite a bit more digging and detective work before it is ready). > + hci_dev_unlock(hdev); > + return; > + } > + > if (ev->status) { > hci_conn_del(hcon); > hci_dev_unlock(hdev); regards, dan carpenter _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-10 10:49 ` Dan Carpenter @ 2020-09-10 14:58 ` Anmol Karn 2020-09-12 9:10 ` Anmol Karn 1 sibling, 0 replies; 12+ messages in thread From: Anmol Karn @ 2020-09-10 14:58 UTC (permalink / raw) To: Dan Carpenter Cc: syzbot+0bef568258653cff272f, johan.hedberg, netdev, marcel, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem On Thu, Sep 10, 2020 at 01:49:18PM +0300, Dan Carpenter wrote: > On Thu, Sep 10, 2020 at 10:04:24AM +0530, Anmol Karn wrote: > > Prevent hci_phy_link_complete_evt() from dereferencing 'hcon->amp_mgr' > > as NULL. Fix it by adding pointer check for it. > > > > Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com > > Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f > > Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> > > --- > > net/bluetooth/hci_event.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > > index 4b7fc430793c..871e16804433 100644 > > --- a/net/bluetooth/hci_event.c > > +++ b/net/bluetooth/hci_event.c > > @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > > return; > > } > > > > + if (IS_ERR_OR_NULL(hcon->amp_mgr)) { > > It can't be an error pointer. Shouldn't we call hci_conn_del() on this > path? Try to find the Fixes tag to explain how this bug was introduced. > > (Don't rush to send a v2. The patch requires quite a bit more digging > and detective work before it is ready). > > > + hci_dev_unlock(hdev); > > + return; > > + } > > + > > if (ev->status) { > > hci_conn_del(hcon); > > hci_dev_unlock(hdev); > > regards, > dan carpenter > Sure sir, will work on it, thanks for your review. Anmol Karn _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-10 10:49 ` Dan Carpenter 2020-09-10 14:58 ` Anmol Karn @ 2020-09-12 9:10 ` Anmol Karn 2020-09-14 15:44 ` Dan Carpenter 1 sibling, 1 reply; 12+ messages in thread From: Anmol Karn @ 2020-09-12 9:10 UTC (permalink / raw) To: Dan Carpenter Cc: syzbot+0bef568258653cff272f, johan.hedberg, netdev, marcel, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem On Thu, Sep 10, 2020 at 01:49:18PM +0300, Dan Carpenter wrote: > On Thu, Sep 10, 2020 at 10:04:24AM +0530, Anmol Karn wrote: > > Prevent hci_phy_link_complete_evt() from dereferencing 'hcon->amp_mgr' > > as NULL. Fix it by adding pointer check for it. > > > > Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com > > Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f > > Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> > > --- > > net/bluetooth/hci_event.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > > index 4b7fc430793c..871e16804433 100644 > > --- a/net/bluetooth/hci_event.c > > +++ b/net/bluetooth/hci_event.c > > @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > > return; > > } > > > > + if (IS_ERR_OR_NULL(hcon->amp_mgr)) { > > It can't be an error pointer. Shouldn't we call hci_conn_del() on this > path? Try to find the Fixes tag to explain how this bug was introduced. > > (Don't rush to send a v2. The patch requires quite a bit more digging > and detective work before it is ready). > > > + hci_dev_unlock(hdev); > > + return; > > + } > > + > > if (ev->status) { > > hci_conn_del(hcon); > > hci_dev_unlock(hdev); > > regards, > dan carpenter > Sir, I need little advice in continuing with this Patch, I have looked into the Bisected logs and the problem occurs from this commit: 941992d29447 ("ethernet: amd: use IS_ENABLED() instead of checking for built-in or module") Here is a diff of patch which i modified from last patch, diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 4b7fc430793c..6ce435064e0b 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4936,6 +4936,12 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, return; } + if (!hcon->amp_mgr) { + hci_conn_del(hcon); + hci_dev_unlock(hdev); + return; + } + if (ev->status) { hci_conn_del(hcon); hci_dev_unlock(hdev); The value of 'hcon->amp_mgr' getting NULL due to hci_conn_hash_lookup_handle call , and there is not any checks there for the members of hcon, which enables hci_phy_link_complete_evt() to dereference 'hcon->amp_mgr' as NULL. please suggest improvements to this patch. Regards, Anmol _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-12 9:10 ` Anmol Karn @ 2020-09-14 15:44 ` Dan Carpenter 2020-09-14 18:37 ` Anmol Karn 2020-09-29 17:32 ` Anmol Karn 0 siblings, 2 replies; 12+ messages in thread From: Dan Carpenter @ 2020-09-14 15:44 UTC (permalink / raw) To: Anmol Karn Cc: syzbot+0bef568258653cff272f, johan.hedberg, netdev, marcel, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem On Sat, Sep 12, 2020 at 02:40:28PM +0530, Anmol Karn wrote: > On Thu, Sep 10, 2020 at 01:49:18PM +0300, Dan Carpenter wrote: > > On Thu, Sep 10, 2020 at 10:04:24AM +0530, Anmol Karn wrote: > > > Prevent hci_phy_link_complete_evt() from dereferencing 'hcon->amp_mgr' > > > as NULL. Fix it by adding pointer check for it. > > > > > > Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com > > > Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f > > > Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> > > > --- > > > net/bluetooth/hci_event.c | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > > > index 4b7fc430793c..871e16804433 100644 > > > --- a/net/bluetooth/hci_event.c > > > +++ b/net/bluetooth/hci_event.c > > > @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > > > return; > > > } > > > > > > + if (IS_ERR_OR_NULL(hcon->amp_mgr)) { > > > > It can't be an error pointer. Shouldn't we call hci_conn_del() on this > > path? Try to find the Fixes tag to explain how this bug was introduced. > > > > (Don't rush to send a v2. The patch requires quite a bit more digging > > and detective work before it is ready). > > > > > + hci_dev_unlock(hdev); > > > + return; > > > + } > > > + > > > if (ev->status) { > > > hci_conn_del(hcon); > > > hci_dev_unlock(hdev); > > > > regards, > > dan carpenter > > > > Sir, > > I need little advice in continuing with this Patch, > > I have looked into the Bisected logs and the problem occurs from this commit: > > 941992d29447 ("ethernet: amd: use IS_ENABLED() instead of checking for built-in or module") > That's just the patch which made the code testable by syzbot. It didn't introduce the bug. > > Here is a diff of patch which i modified from last patch, > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > index 4b7fc430793c..6ce435064e0b 100644 > --- a/net/bluetooth/hci_event.c > +++ b/net/bluetooth/hci_event.c > @@ -4936,6 +4936,12 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > return; > } > > + if (!hcon->amp_mgr) { > + hci_conn_del(hcon); > + hci_dev_unlock(hdev); I have no idea if calling hci_conn_del() is really the correct, thing. I don't know the code at all. Anyway, do some research and figure out for sure what the correct thing is. Also look for similar bugs in other places where hcon->amp_mgr is dereferenced. For example, amp_read_loc_assoc_final_data() seems to have a similar bug. regards, dan carpenter _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-14 15:44 ` Dan Carpenter @ 2020-09-14 18:37 ` Anmol Karn 2020-09-29 17:32 ` Anmol Karn 1 sibling, 0 replies; 12+ messages in thread From: Anmol Karn @ 2020-09-14 18:37 UTC (permalink / raw) To: Dan Carpenter Cc: syzbot+0bef568258653cff272f, johan.hedberg, netdev, marcel, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem Hello Sir, > > I have looked into the Bisected logs and the problem occurs from this commit: > > > > 941992d29447 ("ethernet: amd: use IS_ENABLED() instead of checking for built-in or module") > > > > That's just the patch which made the code testable by syzbot. It didn't > introduce the bug. > > > > > Here is a diff of patch which i modified from last patch, > > > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > > index 4b7fc430793c..6ce435064e0b 100644 > > --- a/net/bluetooth/hci_event.c > > +++ b/net/bluetooth/hci_event.c > > @@ -4936,6 +4936,12 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > > return; > > } > > > > + if (!hcon->amp_mgr) { > > + hci_conn_del(hcon); > > + hci_dev_unlock(hdev); > > I have no idea if calling hci_conn_del() is really the correct, thing. > I don't know the code at all. Anyway, do some research and figure out > for sure what the correct thing is. I have created my patch on the basis of the already applied conditions handling in this function, i.e whenever NULL dereference occurs, connection cleanup is required hence, hci_conn_del() is used here. Will see if anything else could be done. > > Also look for similar bugs in other places where hcon->amp_mgr is > dereferenced. For example, amp_read_loc_assoc_final_data() seems to > have a similar bug. > Sure sir will look into it. > regards, > dan carpenter > Thanks, Anmol _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply [flat|nested] 12+ messages in thread
* [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-14 15:44 ` Dan Carpenter 2020-09-14 18:37 ` Anmol Karn @ 2020-09-29 17:32 ` Anmol Karn 2020-09-30 14:18 ` Anmol Karn 1 sibling, 1 reply; 12+ messages in thread From: Anmol Karn @ 2020-09-29 17:32 UTC (permalink / raw) To: marcel, johan.hedberg Cc: netdev, syzbot+0bef568258653cff272f, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem AMP_MGR is getting derefernced in hci_phy_link_complete_evt(), when called from hci_event_packet() and there is a possibility, that hcon->amp_mgr may not be found when accessing after initialization of hcon. - net/bluetooth/hci_event.c:4945 The bug seems to get triggered in this line: bredr_hcon = hcon->amp_mgr->l2cap_conn->hcon; Fix it by adding a NULL check for the hcon->amp_mgr before checking the ev-status. Fixes: d5e911928bd8 ("Bluetooth: AMP: Process Physical Link Complete evt") Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> --- Cahnge in v2: - Replaced IS_ERR_OR_NULL check with NULL check only (Suggested by: Dan Carpenter <dan.carpenter@oracle.com>) - Added "Fixes:" tag (Suggested by: Dan Carpenter <dan.carpenter@oracle.com>) net/bluetooth/hci_event.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 4b7fc430793c..b084142c578e 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, return; } + if (!hcon->amp_mgr) { + hci_dev_unlock(hdev); + return 0; + } + if (ev->status) { hci_conn_del(hcon); hci_dev_unlock(hdev); -- 2.28.0 _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply related [flat|nested] 12+ messages in thread
* [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-29 17:32 ` Anmol Karn @ 2020-09-30 14:18 ` Anmol Karn 2020-10-01 7:06 ` Marcel Holtmann 0 siblings, 1 reply; 12+ messages in thread From: Anmol Karn @ 2020-09-30 14:18 UTC (permalink / raw) To: marcel, johan.hedberg Cc: netdev, syzbot+0bef568258653cff272f, syzkaller-bugs, linux-kernel, linux-bluetooth, kuba, linux-kernel-mentees, davem AMP_MGR is getting derefernced in hci_phy_link_complete_evt(), when called from hci_event_packet() and there is a possibility, that hcon->amp_mgr may not be found when accessing after initialization of hcon. - net/bluetooth/hci_event.c:4945 The bug seems to get triggered in this line: bredr_hcon = hcon->amp_mgr->l2cap_conn->hcon; Fix it by adding a NULL check for the hcon->amp_mgr before checking the ev-status. Fixes: d5e911928bd8 ("Bluetooth: AMP: Process Physical Link Complete evt") Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> --- Change in v3: - changed return o; to return; (Reported-by: kernel test robot <lkp@intel.com> ) net/bluetooth/hci_event.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 4b7fc430793c..bbe0ca42cad2 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, return; } + if (!hcon->amp_mgr) { + hci_dev_unlock(hdev); + return; + } + if (ev->status) { hci_conn_del(hcon); hci_dev_unlock(hdev); -- 2.28.0 _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-09-30 14:18 ` Anmol Karn @ 2020-10-01 7:06 ` Marcel Holtmann 2020-10-01 7:45 ` Anmol Karn 0 siblings, 1 reply; 12+ messages in thread From: Marcel Holtmann @ 2020-10-01 7:06 UTC (permalink / raw) To: Anmol Karn Cc: Johan Hedberg, open list:NETWORKING [GENERAL], syzbot+0bef568258653cff272f, syzkaller-bugs, open list, linux-bluetooth, Jakub Kicinski, linux-kernel-mentees, David S. Miller Hi Anmol, > AMP_MGR is getting derefernced in hci_phy_link_complete_evt(), when called from hci_event_packet() and there is a possibility, that hcon->amp_mgr may not be found when accessing after initialization of hcon. > > - net/bluetooth/hci_event.c:4945 > The bug seems to get triggered in this line: > > bredr_hcon = hcon->amp_mgr->l2cap_conn->hcon; > > Fix it by adding a NULL check for the hcon->amp_mgr before checking the ev-status. > > Fixes: d5e911928bd8 ("Bluetooth: AMP: Process Physical Link Complete evt") > Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f > Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> > --- > Change in v3: > - changed return o; to return; (Reported-by: kernel test robot <lkp@intel.com> > ) > > net/bluetooth/hci_event.c | 5 +++++ > 1 file changed, 5 insertions(+) patch has been applied to bluetooth-next tree. Regards Marcel _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() 2020-10-01 7:06 ` Marcel Holtmann @ 2020-10-01 7:45 ` Anmol Karn 0 siblings, 0 replies; 12+ messages in thread From: Anmol Karn @ 2020-10-01 7:45 UTC (permalink / raw) To: Marcel Holtmann Cc: Johan Hedberg, open list:NETWORKING [GENERAL], syzbot+0bef568258653cff272f, syzkaller-bugs, open list, linux-bluetooth, Jakub Kicinski, linux-kernel-mentees, David S. Miller On Thu, Oct 01, 2020 at 09:06:42AM +0200, Marcel Holtmann wrote: > Hi Anmol, > > > AMP_MGR is getting derefernced in hci_phy_link_complete_evt(), when called from hci_event_packet() and there is a possibility, that hcon->amp_mgr may not be found when accessing after initialization of hcon. > > > > - net/bluetooth/hci_event.c:4945 > > The bug seems to get triggered in this line: > > > > bredr_hcon = hcon->amp_mgr->l2cap_conn->hcon; > > > > Fix it by adding a NULL check for the hcon->amp_mgr before checking the ev-status. > > > > Fixes: d5e911928bd8 ("Bluetooth: AMP: Process Physical Link Complete evt") > > Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com > > Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f > > Signed-off-by: Anmol Karn <anmol.karan123@gmail.com> > > --- > > Change in v3: > > - changed return o; to return; (Reported-by: kernel test robot <lkp@intel.com> > > ) > > > > net/bluetooth/hci_event.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > patch has been applied to bluetooth-next tree. > > Regards > > Marcel > Thank you :) Best, Anmol _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees ^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2020-10-01 7:45 UTC | newest] Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-09-10 4:34 [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() Anmol Karn 2020-09-10 5:06 ` Eric Biggers 2020-09-10 6:02 ` Anmol Karn 2020-09-10 10:49 ` Dan Carpenter 2020-09-10 14:58 ` Anmol Karn 2020-09-12 9:10 ` Anmol Karn 2020-09-14 15:44 ` Dan Carpenter 2020-09-14 18:37 ` Anmol Karn 2020-09-29 17:32 ` Anmol Karn 2020-09-30 14:18 ` Anmol Karn 2020-10-01 7:06 ` Marcel Holtmann 2020-10-01 7:45 ` Anmol Karn
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