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* [PATCH] bna: integer overflow bug in debugfs
@ 2017-03-17 20:52 ` Dan Carpenter
  0 siblings, 0 replies; 5+ messages in thread
From: Dan Carpenter @ 2017-03-17 20:52 UTC (permalink / raw)
  To: Rasesh Mody, Krishna Gudipati
  Cc: Sudarsana Kalluru, Dept-GELinuxNICDev, netdev, kernel-janitors

We could allocate less memory than intended because we do:

	bnad->regdata = kzalloc(len << 2, GFP_KERNEL);

The shift can overflow leading to a crash.  This is debugfs code so the
impact is very small.

Fixes: 7afc5dbde091 ("bna: Add debugfs interface.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
index 05c1c1dd7751..cebfe3bd086e 100644
--- a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
+++ b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
@@ -325,7 +325,7 @@ bnad_debugfs_write_regrd(struct file *file, const char __user *buf,
 		return PTR_ERR(kern_buf);
 
 	rc = sscanf(kern_buf, "%x:%x", &addr, &len);
-	if (rc < 2) {
+	if (rc < 2 || len > UINT_MAX >> 2) {
 		netdev_warn(bnad->netdev, "failed to read user buffer\n");
 		kfree(kern_buf);
 		return -EINVAL;

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* [PATCH] bna: integer overflow bug in debugfs
@ 2017-03-17 20:52 ` Dan Carpenter
  0 siblings, 0 replies; 5+ messages in thread
From: Dan Carpenter @ 2017-03-17 20:52 UTC (permalink / raw)
  To: Rasesh Mody, Krishna Gudipati
  Cc: Sudarsana Kalluru, Dept-GELinuxNICDev, netdev, kernel-janitors

We could allocate less memory than intended because we do:

	bnad->regdata = kzalloc(len << 2, GFP_KERNEL);

The shift can overflow leading to a crash.  This is debugfs code so the
impact is very small.

Fixes: 7afc5dbde091 ("bna: Add debugfs interface.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
index 05c1c1dd7751..cebfe3bd086e 100644
--- a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
+++ b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
@@ -325,7 +325,7 @@ bnad_debugfs_write_regrd(struct file *file, const char __user *buf,
 		return PTR_ERR(kern_buf);
 
 	rc = sscanf(kern_buf, "%x:%x", &addr, &len);
-	if (rc < 2) {
+	if (rc < 2 || len > UINT_MAX >> 2) {
 		netdev_warn(bnad->netdev, "failed to read user buffer\n");
 		kfree(kern_buf);
 		return -EINVAL;

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* RE: [PATCH] bna: integer overflow bug in debugfs
  2017-03-17 20:52 ` Dan Carpenter
  (?)
@ 2017-03-21  1:14 ` Mody, Rasesh
  -1 siblings, 0 replies; 5+ messages in thread
From: Mody, Rasesh @ 2017-03-21  1:14 UTC (permalink / raw)
  To: Dan Carpenter, Krishna Gudipati
  Cc: Kalluru, Sudarsana, Dept-GE Linux NIC Dev, netdev, kernel-janitors

> From: Dan Carpenter [mailto:dan.carpenter@oracle.com]
> Sent: Friday, March 17, 2017 1:53 PM
> 
> We could allocate less memory than intended because we do:
> 
> 	bnad->regdata = kzalloc(len << 2, GFP_KERNEL);
> 
> The shift can overflow leading to a crash.  This is debugfs code so the impact
> is very small.
> 
> Fixes: 7afc5dbde091 ("bna: Add debugfs interface.")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
> b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
> index 05c1c1dd7751..cebfe3bd086e 100644
> --- a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
> +++ b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
> @@ -325,7 +325,7 @@ bnad_debugfs_write_regrd(struct file *file, const
> char __user *buf,
>  		return PTR_ERR(kern_buf);
> 
>  	rc = sscanf(kern_buf, "%x:%x", &addr, &len);
> -	if (rc < 2) {
> +	if (rc < 2 || len > UINT_MAX >> 2) {
>  		netdev_warn(bnad->netdev, "failed to read user buffer\n");
>  		kfree(kern_buf);
>  		return -EINVAL;

You are correct, thanks Dan for adding the check.

Acked-by: Rasesh Mody <rasesh.mody@cavium.com>

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] bna: integer overflow bug in debugfs
  2017-03-17 20:52 ` Dan Carpenter
@ 2017-03-22  0:43   ` David Miller
  -1 siblings, 0 replies; 5+ messages in thread
From: David Miller @ 2017-03-22  0:43 UTC (permalink / raw)
  To: dan.carpenter
  Cc: rasesh.mody, kgudipat, sudarsana.kalluru, Dept-GELinuxNICDev,
	netdev, kernel-janitors

From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 17 Mar 2017 23:52:35 +0300

> We could allocate less memory than intended because we do:
> 
> 	bnad->regdata = kzalloc(len << 2, GFP_KERNEL);
> 
> The shift can overflow leading to a crash.  This is debugfs code so the
> impact is very small.
> 
> Fixes: 7afc5dbde091 ("bna: Add debugfs interface.")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Applied.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] bna: integer overflow bug in debugfs
@ 2017-03-22  0:43   ` David Miller
  0 siblings, 0 replies; 5+ messages in thread
From: David Miller @ 2017-03-22  0:43 UTC (permalink / raw)
  To: dan.carpenter
  Cc: rasesh.mody, kgudipat, sudarsana.kalluru, Dept-GELinuxNICDev,
	netdev, kernel-janitors

From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 17 Mar 2017 23:52:35 +0300

> We could allocate less memory than intended because we do:
> 
> 	bnad->regdata = kzalloc(len << 2, GFP_KERNEL);
> 
> The shift can overflow leading to a crash.  This is debugfs code so the
> impact is very small.
> 
> Fixes: 7afc5dbde091 ("bna: Add debugfs interface.")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Applied.

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2017-03-22  0:44 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-03-17 20:52 [PATCH] bna: integer overflow bug in debugfs Dan Carpenter
2017-03-17 20:52 ` Dan Carpenter
2017-03-21  1:14 ` Mody, Rasesh
2017-03-22  0:43 ` David Miller
2017-03-22  0:43   ` David Miller

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