[PATCH] net: qrtr: fix memory leak in qrtr_local_enqueue

Syzbot reported memory leak in qrtr. The problem was in unputted
struct sock. qrtr_local_enqueue() function calls qrtr_port_lookup()
which takes sock reference if port was found. Then there is the following
check:

if (!ipc || &ipc->sk == skb->sk) {
	...
	return -ENODEV;
}

Since we should drop the reference before returning from this function and
ipc can be non-NULL inside this if, we should add qrtr_port_put() inside
this if.

Fixes: bdabad3e363d ("net: Add Qualcomm IPC router")
Reported-and-tested-by: syzbot+35a511c72ea7356cdcf3@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---
 net/qrtr/qrtr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index e6f4a6202f82..d5ce428d0b25 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c

@@ -839,6 +839,8 @@ static int qrtr_local_enqueue(struct qrtr_node *node, struct sk_buff *skb,
 
 	ipc = qrtr_port_lookup(to->sq_port);
 	if (!ipc || &ipc->sk == skb->sk) { /* do not send to self */
+		if (ipc)
+			qrtr_port_put(ipc);
 		kfree_skb(skb);
 		return -ENODEV;
 	}

-- 
2.32.0

On Thu, Jul 22, 2021 at 07:16:25PM +0300, Pavel Skripkin wrote:

Syzbot reported memory leak in qrtr. The problem was in unputted
struct sock. qrtr_local_enqueue() function calls qrtr_port_lookup()
which takes sock reference if port was found. Then there is the following
check:

if (!ipc || &ipc->sk == skb->sk) {
	...
	return -ENODEV;
}

Since we should drop the reference before returning from this function and
ipc can be non-NULL inside this if, we should add qrtr_port_put() inside
this if.

Fixes: bdabad3e363d ("net: Add Qualcomm IPC router")
Reported-and-tested-by: syzbot+35a511c72ea7356cdcf3@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>

Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>

It'd be good if this patch can be extended to fix one more corner case here:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/qrtr/qrtr.c#n522

Thanks,
Mani

On Fri, 23 Jul 2021 17:57:53 +0530
Manivannan Sadhasivam [off-list ref] wrote:

On Thu, Jul 22, 2021 at 07:16:25PM +0300, Pavel Skripkin wrote:

quoted

Syzbot reported memory leak in qrtr. The problem was in unputted
struct sock. qrtr_local_enqueue() function calls qrtr_port_lookup()
which takes sock reference if port was found. Then there is the
following check:

if (!ipc || &ipc->sk == skb->sk) {
	...
	return -ENODEV;
}

Since we should drop the reference before returning from this
function and ipc can be non-NULL inside this if, we should add
qrtr_port_put() inside this if.

Fixes: bdabad3e363d ("net: Add Qualcomm IPC router")
Reported-and-tested-by:
syzbot+35a511c72ea7356cdcf3@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>

Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>

It'd be good if this patch can be extended to fix one more corner
case here:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/qrtr/qrtr.c#n522

Thanks,
Mani

Hi, Manivannan!

I will fix leak there too in v2, thank you! 



With regards,
Pavel Skripkin

quoted

---
 net/qrtr/qrtr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index e6f4a6202f82..d5ce428d0b25 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c

@@ -839,6 +839,8 @@ static int qrtr_local_enqueue(struct qrtr_node

*node, struct sk_buff *skb, 
 	ipc = qrtr_port_lookup(to->sq_port);
 	if (!ipc || &ipc->sk == skb->sk) { /* do not send to self
*/
+		if (ipc)
+			qrtr_port_put(ipc);
 		kfree_skb(skb);
 		return -ENODEV;
 	}
-- 
2.32.0

Syzbot reported memory leak in qrtr. The problem was in unputted
struct sock. qrtr_local_enqueue() function calls qrtr_port_lookup()
which takes sock reference if port was found. Then there is the following
check:

if (!ipc || &ipc->sk == skb->sk) {
	...
	return -ENODEV;
}

Since we should drop the reference before returning from this function and
ipc can be non-NULL inside this if, we should add qrtr_port_put() inside
this if.

The similar corner case is in qrtr_endpoint_post() as Manivannan
reported. In case of sock_queue_rcv_skb() failure we need to put
port reference to avoid leaking struct sock pointer.

Fixes: e04df98adf7d ("net: qrtr: Remove receive worker")
Fixes: bdabad3e363d ("net: Add Qualcomm IPC router")
Reported-and-tested-by: syzbot+35a511c72ea7356cdcf3@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---

Changes in v2:
	Added missing qrtr_port_put() in qrtr_endpoint_post() as Manivannan
	reported.

---
 net/qrtr/qrtr.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index b34358282f37..a8b2c9b21a8d 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c

@@ -514,8 +514,10 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
 		if (!ipc)
 			goto err;
 
-		if (sock_queue_rcv_skb(&ipc->sk, skb))
+		if (sock_queue_rcv_skb(&ipc->sk, skb)) {
+			qrtr_port_put(ipc);
 			goto err;
+		}
 
 		qrtr_port_put(ipc);
 	}

@@ -850,6 +852,8 @@ static int qrtr_local_enqueue(struct qrtr_node *node, struct sk_buff *skb,
 
 	ipc = qrtr_port_lookup(to->sq_port);
 	if (!ipc || &ipc->sk == skb->sk) { /* do not send to self */
+		if (ipc)
+			qrtr_port_put(ipc);
 		kfree_skb(skb);
 		return -ENODEV;
 	}

-- 
2.32.0

On Fri, Jul 23, 2021 at 06:31:32PM +0300, Pavel Skripkin wrote:

Syzbot reported memory leak in qrtr. The problem was in unputted
struct sock. qrtr_local_enqueue() function calls qrtr_port_lookup()
which takes sock reference if port was found. Then there is the following
check:

if (!ipc || &ipc->sk == skb->sk) {
	...
	return -ENODEV;
}

Since we should drop the reference before returning from this function and
ipc can be non-NULL inside this if, we should add qrtr_port_put() inside
this if.

The similar corner case is in qrtr_endpoint_post() as Manivannan
reported. In case of sock_queue_rcv_skb() failure we need to put
port reference to avoid leaking struct sock pointer.

Fixes: e04df98adf7d ("net: qrtr: Remove receive worker")
Fixes: bdabad3e363d ("net: Add Qualcomm IPC router")
Reported-and-tested-by: syzbot+35a511c72ea7356cdcf3@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>

Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>

Thanks,
Mani

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Fri, 23 Jul 2021 18:31:32 +0300 you wrote:

Syzbot reported memory leak in qrtr. The problem was in unputted
struct sock. qrtr_local_enqueue() function calls qrtr_port_lookup()
which takes sock reference if port was found. Then there is the following
check:

if (!ipc || &ipc->sk == skb->sk) {
	...
	return -ENODEV;
}

[...]

Here is the summary with links:
  - [v2] net: qrtr: fix memory leaks
    https://git.kernel.org/netdev/net/c/52f3456a96c0

You are awesome, thank you!
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