[PATCH] libertas_tf: prevent underflow in process_cmdrequest()

[PATCH] libertas_tf: prevent underflow in process_cmdrequest()

[Dan Carpenter]

If recvlength is less than MESSAGE_HEADER_LEN (4) we would end up
corrupting memory.

Fixes: c305a19a0d0a ("libertas_tf: usb specific functions")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
This is from static analysis.  I'm not positive that this is a real
bug, but it's harmless to check.

diff --git a/drivers/net/wireless/marvell/libertas_tf/if_usb.c b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
index e92fc5001171..789337ea676a 100644
--- a/drivers/net/wireless/marvell/libertas_tf/if_usb.c
+++ b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
@@ -605,9 +605,10 @@ static inline void process_cmdrequest(int recvlength, uint8_t *recvbuff,
 {
 	unsigned long flags;
 
-	if (recvlength > LBS_CMD_BUFFER_SIZE) {
+	if (recvlength < MESSAGE_HEADER_LEN ||
+	    recvlength > LBS_CMD_BUFFER_SIZE) {
 		lbtf_deb_usbd(&cardp->udev->dev,
-			     "The receive buffer is too large\n");
+			     "The receive buffer is invalid: %d\n", recvlength);
 		kfree_skb(skb);
 		return;
 	}

[PATCH] libertas_tf: prevent underflow in process_cmdrequest()

[Dan Carpenter]

If recvlength is less than MESSAGE_HEADER_LEN (4) we would end up
corrupting memory.

Fixes: c305a19a0d0a ("libertas_tf: usb specific functions")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
This is from static analysis.  I'm not positive that this is a real
bug, but it's harmless to check.

diff --git a/drivers/net/wireless/marvell/libertas_tf/if_usb.c b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
index e92fc5001171..789337ea676a 100644
--- a/drivers/net/wireless/marvell/libertas_tf/if_usb.c
+++ b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
@@ -605,9 +605,10 @@ static inline void process_cmdrequest(int recvlength, uint8_t *recvbuff,
 {
 	unsigned long flags;
 
-	if (recvlength > LBS_CMD_BUFFER_SIZE) {
+	if (recvlength < MESSAGE_HEADER_LEN ||
+	    recvlength > LBS_CMD_BUFFER_SIZE) {
 		lbtf_deb_usbd(&cardp->udev->dev,
-			     "The receive buffer is too large\n");
+			     "The receive buffer is invalid: %d\n", recvlength);
 		kfree_skb(skb);
 		return;
 	}

re:[PATCH] libertas_tf: prevent underflow in process_cmdrequest()

[Walter Harms]

If recvlength is less than MESSAGE_HEADER_LEN (4) we would end up
corrupting memory.

Fixes: c305a19a0d0a ("libertas_tf: usb specific functions")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
This is from static analysis.  I'm not positive that this is a real
bug, but it's harmless to check.

diff --git a/drivers/net/wireless/marvell/libertas_tf/if_usb.c
b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
index e92fc5001171..789337ea676a 100644
--- a/drivers/net/wireless/marvell/libertas_tf/if_usb.c
+++ b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
@@ -605,9 +605,10 @@ static inline void process_cmdrequest(int recvlength,
uint8_t *recvbuff,
 {
 	unsigned long flags;
 -	if (recvlength > LBS_CMD_BUFFER_SIZE) {
+	if (recvlength < MESSAGE_HEADER_LEN ||
+	    recvlength > LBS_CMD_BUFFER_SIZE) {
 		lbtf_deb_usbd(&cardp->udev->dev,
-			     "The receive buffer is too large\n");
+			     "The receive buffer is invalid: %d\n", recvlength);

The wording here is a bit unfortunate, and give the user a false impression (at
least me).
The problem is the paketsize not the buffer.
therefor i suggest to change that into:
 "received invalid paketsize %d\n"

just my 2 cents,

re,
 wh
 		kfree_skb(skb);
 		return;
 	}

re:[PATCH] libertas_tf: prevent underflow in process_cmdrequest()

[Walter Harms]

If recvlength is less than MESSAGE_HEADER_LEN (4) we would end up
corrupting memory.

Fixes: c305a19a0d0a ("libertas_tf: usb specific functions")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
This is from static analysis.  I'm not positive that this is a real
bug, but it's harmless to check.

diff --git a/drivers/net/wireless/marvell/libertas_tf/if_usb.c
b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
index e92fc5001171..789337ea676a 100644
--- a/drivers/net/wireless/marvell/libertas_tf/if_usb.c
+++ b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
@@ -605,9 +605,10 @@ static inline void process_cmdrequest(int recvlength,
uint8_t *recvbuff,
 {
 	unsigned long flags;
 -	if (recvlength > LBS_CMD_BUFFER_SIZE) {
+	if (recvlength < MESSAGE_HEADER_LEN ||
+	    recvlength > LBS_CMD_BUFFER_SIZE) {
 		lbtf_deb_usbd(&cardp->udev->dev,
-			     "The receive buffer is too large\n");
+			     "The receive buffer is invalid: %d\n", recvlength);

The wording here is a bit unfortunate, and give the user a false impression (at
least me).
The problem is the paketsize not the buffer.
therefor i suggest to change that into:
 "received invalid paketsize %d\n"

just my 2 cents,

re,
 wh
 		kfree_skb(skb);
 		return;
 	}

Re: [PATCH] libertas_tf: prevent underflow in process_cmdrequest()

[Kalle Valo]

Dan Carpenter <dan.carpenter@oracle.com> wrote:

> If recvlength is less than MESSAGE_HEADER_LEN (4) we would end up
> corrupting memory.
> 
> Fixes: c305a19a0d0a ("libertas_tf: usb specific functions")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Patch applied to wireless-drivers-next.git, thanks.

3348ef6a6a12 libertas_tf: prevent underflow in process_cmdrequest()

-- 
https://patchwork.kernel.org/patch/10565197/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Re: [PATCH] libertas_tf: prevent underflow in process_cmdrequest()

[Kalle Valo]

Dan Carpenter <dan.carpenter@oracle.com> wrote:

> If recvlength is less than MESSAGE_HEADER_LEN (4) we would end up
> corrupting memory.
> 
> Fixes: c305a19a0d0a ("libertas_tf: usb specific functions")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Patch applied to wireless-drivers-next.git, thanks.

3348ef6a6a12 libertas_tf: prevent underflow in process_cmdrequest()

-- 
https://patchwork.kernel.org/patch/10565197/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches