Re: [PATCH] bna: integer overflow bug in debugfs

2017-03-21 Thread David Miller 
From: Dan Carpenter 
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 

Applied.

RE: [PATCH] bna: integer overflow bug in debugfs

2017-03-20 Thread Mody, Rasesh 
> From: Dan Carpenter [mailto:dan.carpen...@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 
> 
> 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", , );
> - 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

[PATCH] bna: integer overflow bug in debugfs

2017-03-17 Thread Dan Carpenter 
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 

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", , );
-   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;