ieee802154: 6lowpan: fix possible NULL deref in lowpan_device_event()

PATCH In review Eric Dumazet 3 participants 5 messages Mar 5, 2018 – Mar 9, 2018

Subsystems (3)

Networking Network drivers IEEE 802.15.4

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Eric Dumazet

author

2018-03-05 16:51 UTC #0 lore raw

PATCH 1/1 ieee802154: 6lowpan: fix possible NULL deref in lowpan_device_event()

From: Eric Dumazet <[email protected]>

A tun device type can trivially be set to arbitrary value using TUNSETLINK ioctl().

Therefore, lowpan_device_event() must really check that ieee802154_ptr is not NULL.

Fixes 2c88b5283f60d ("ieee802154: 6lowpan: remove check on null")

Signed-off-by Eric Dumazet <[email protected]>

Cc Alexander Aring <[email protected]>

Cc Stefan Schmidt <[email protected]>

Reported-by syzbot <[email protected]>

---
net/ieee802154/6lowpan/core.c | 12 ++++++++----

 1 file changed, 8 insertions(+), 4 deletions(-)

net/ieee802154/6lowpan/core.c +8 -4

index 974765b7d92a..e9f0489e4229 100644
@@ -206,9 +206,13 @@ static inline void lowpan_netlink_fini(void)
 static int lowpan_device_event(struct notifier_block *unused,
 			       unsigned long event, void *ptr)
 {
-	struct net_device *wdev = netdev_notifier_info_to_dev(ptr);
+	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
+	struct wpan_dev *wpan_dev;
 
-	if (wdev->type != ARPHRD_IEEE802154)
+	if (ndev->type != ARPHRD_IEEE802154)
+		return NOTIFY_DONE;
+	wpan_dev = ndev->ieee802154_ptr;
+	if (!wpan_dev)
 		return NOTIFY_DONE;
 
 	switch (event) {

@@ -217,8 +221,8 @@ static int lowpan_device_event(struct notifier_block *unused,
 		 * also delete possible lowpan interfaces which belongs
 		 * to the wpan interface.
 		 */
-		if (wdev->ieee802154_ptr->lowpan_dev)
-			lowpan_dellink(wdev->ieee802154_ptr->lowpan_dev, NULL);
+		if (wpan_dev->lowpan_dev)
+			lowpan_dellink(wpan_dev->lowpan_dev, NULL);
 		break;
 	default:
 		return NOTIFY_DONE;

David Miller

maintainer

2018-03-05 17:00 UTC #1 lore raw

From: Eric Dumazet <[email protected]>
Date: Mon, 05 Mar 2018 08:51:03 -0800

Quoted 5 lines

From: Eric Dumazet <[email protected]>
A tun device type can trivially be set to arbitrary value using TUNSETLINK ioctl().

Quoted 8 lines

Therefore, lowpan_device_event() must really check that ieee802154_ptr is not NULL.
Fixes 2c88b5283f60d ("ieee802154: 6lowpan: remove check on null")
Signed-off-by Eric Dumazet <[email protected]>
Cc Alexander Aring <[email protected]>
Cc Stefan Schmidt <[email protected]>
Reported-by syzbot <[email protected]>

Adding linux-wpan list.

Quoted 36 lines

---
net/ieee802154/6lowpan/core.c | 12 ++++++++----

 1 file changed, 8 insertions(+), 4 deletions(-)

net/ieee802154/6lowpan/core.c +8 -4

index 974765b7d92a..e9f0489e4229 100644
@@ -206,9 +206,13 @@ static inline void lowpan_netlink_fini(void)
 static int lowpan_device_event(struct notifier_block *unused,
 			       unsigned long event, void *ptr)
 {
-	struct net_device *wdev = netdev_notifier_info_to_dev(ptr);
+	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
+	struct wpan_dev *wpan_dev;
 
-	if (wdev->type != ARPHRD_IEEE802154)
+	if (ndev->type != ARPHRD_IEEE802154)
+		return NOTIFY_DONE;
+	wpan_dev = ndev->ieee802154_ptr;
+	if (!wpan_dev)
 		return NOTIFY_DONE;
 
 	switch (event) {

@@ -217,8 +221,8 @@ static int lowpan_device_event(struct notifier_block *unused,
 		 * also delete possible lowpan interfaces which belongs
 		 * to the wpan interface.
 		 */
-		if (wdev->ieee802154_ptr->lowpan_dev)
-			lowpan_dellink(wdev->ieee802154_ptr->lowpan_dev, NULL);
+		if (wpan_dev->lowpan_dev)
+			lowpan_dellink(wpan_dev->lowpan_dev, NULL);
 		break;
 	default:
 		return NOTIFY_DONE;

Stefan Schmidt

Acked-by on v1 1/1

2018-03-06 12:56 UTC #2 lore raw

In reply to Eric Dumazet

Hello.

Quoted 22 lines · Eric Dumazet

From: Eric Dumazet <[email protected]>
A tun device type can trivially be set to arbitrary value using TUNSETLINK ioctl().
Therefore, lowpan_device_event() must really check that ieee802154_ptr is not NULL.
Fixes 2c88b5283f60d ("ieee802154: 6lowpan: remove check on null")
Signed-off-by Eric Dumazet <[email protected]>
Cc Alexander Aring <[email protected]>
Cc Stefan Schmidt <[email protected]>
Reported-by syzbot <[email protected]>
---
net/ieee802154/6lowpan/core.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
net/ieee802154/6lowpan/core.c +0 -0
index 974765b7d92a..e9f0489e4229 100644

net/ieee802154/6lowpan/core.c static inline void lowpan_netlink_fini(void) · line 209

Quoted 5 lines

net/ieee802154/6lowpan/core.c +1 -1

@@ -206,9 +206,13 @@ static inline void lowpan_netlink_fini(void)
 static int lowpan_device_event(struct notifier_block *unused,
 			       unsigned long event, void *ptr)
 {
-	struct net_device *wdev = netdev_notifier_info_to_dev(ptr);
+	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);

Not sure why you think there is a rename from wdev to ndev necessary.
I see this more of a rolled in cosmetic change, but its not a real problem from my side.

Quoted 12 lines

net/ieee802154/6lowpan/core.c +5 -1

+	struct wpan_dev *wpan_dev;
 
-	if (wdev->type != ARPHRD_IEEE802154)
+	if (ndev->type != ARPHRD_IEEE802154)
+		return NOTIFY_DONE;
+	wpan_dev = ndev->ieee802154_ptr;
+	if (!wpan_dev)
 		return NOTIFY_DONE;
 
 	switch (event) {

net/ieee802154/6lowpan/core.c static int lowpan_device_event(struct notifier_block *unused, · line 228

Quoted 10 lines

net/ieee802154/6lowpan/core.c +2 -2

@@ -217,8 +221,8 @@ static int lowpan_device_event(struct notifier_block *unused,
 		 * also delete possible lowpan interfaces which belongs
 		 * to the wpan interface.
 		 */
-		if (wdev->ieee802154_ptr->lowpan_dev)
-			lowpan_dellink(wdev->ieee802154_ptr->lowpan_dev, NULL);
+		if (wpan_dev->lowpan_dev)
+			lowpan_dellink(wpan_dev->lowpan_dev, NULL);
 		break;
 	default:
 		return NOTIFY_DONE;

Thanks a lot for fixing this and syzbot for finding it.

Acked-by Stefan Schmidt <[email protected]>

Dave, could you take this one directly? I have no other patches pending for your net tree (only net-next) and having a pull request for just this patch does not make much sense.

regards
Stefan Schmidt

Stefan Schmidt

2018-03-08 16:21 UTC #3 lore raw

Hello Dave.

Quoted 59 lines · Stefan Schmidt

Hello.
Quoted 22 lines · Eric Dumazet
From: Eric Dumazet <[email protected]>
A tun device type can trivially be set to arbitrary value using TUNSETLINK ioctl().
Therefore, lowpan_device_event() must really check that ieee802154_ptr is not NULL.
Fixes 2c88b5283f60d ("ieee802154: 6lowpan: remove check on null")
Signed-off-by Eric Dumazet <[email protected]>
Cc Alexander Aring <[email protected]>
Cc Stefan Schmidt <[email protected]>
Reported-by syzbot <[email protected]>
---
net/ieee802154/6lowpan/core.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
net/ieee802154/6lowpan/core.c +0 -0
index 974765b7d92a..e9f0489e4229 100644
net/ieee802154/6lowpan/core.c static inline void lowpan_netlink_fini(void) · line 209
Quoted 5 lines
net/ieee802154/6lowpan/core.c +1 -1
@@ -206,9 +206,13 @@ static inline void lowpan_netlink_fini(void)
 static int lowpan_device_event(struct notifier_block *unused,
 			       unsigned long event, void *ptr)
 {
-	struct net_device *wdev = netdev_notifier_info_to_dev(ptr);
+	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
Not sure why you think there is a rename from wdev to ndev necessary.
I see this more of a rolled in cosmetic change, but its not a real problem from my side.
Quoted 12 lines
net/ieee802154/6lowpan/core.c +5 -1
+	struct wpan_dev *wpan_dev;
 
-	if (wdev->type != ARPHRD_IEEE802154)
+	if (ndev->type != ARPHRD_IEEE802154)
+		return NOTIFY_DONE;
+	wpan_dev = ndev->ieee802154_ptr;
+	if (!wpan_dev)
 		return NOTIFY_DONE;
 
 	switch (event) {
net/ieee802154/6lowpan/core.c static int lowpan_device_event(struct notifier_block *unused, · line 228
Quoted 10 lines
net/ieee802154/6lowpan/core.c +2 -2
@@ -217,8 +221,8 @@ static int lowpan_device_event(struct notifier_block *unused,
 		 * also delete possible lowpan interfaces which belongs
 		 * to the wpan interface.
 		 */
-		if (wdev->ieee802154_ptr->lowpan_dev)
-			lowpan_dellink(wdev->ieee802154_ptr->lowpan_dev, NULL);
+		if (wpan_dev->lowpan_dev)
+			lowpan_dellink(wpan_dev->lowpan_dev, NULL);
 		break;
 	default:
 		return NOTIFY_DONE;
Thanks a lot for fixing this and syzbot for finding it.

Quoted 5 lines

Acked-by Stefan Schmidt <[email protected]>
Dave, could you take this one directly? I have no other patches pending for your net tree (only net-next) and having a pull request for just this patch does not make much sense.

Did you miss this or would you prefer if I do a pull request for this single patch? Either way would be fine with me.

regards
Stefan Schmidt

David Miller

maintainer

2018-03-09 16:19 UTC #4 lore raw

From: Stefan Schmidt <[email protected]>
Date: Thu, 8 Mar 2018 17:21:49 +0100

Quoted 2 lines

Did you miss this or would you prefer if I do a pull request for this single patch? Either way would be fine with me.

Sorry, this escaped me.

Applied and queued up for -stable, thanks.