[patch] mlx5: use after free in mlx5_cmd_comp_handler()

[patch] mlx5: use after free in mlx5_cmd_comp_handler()

[Dan Carpenter]

We can't dereference "ent" after passing it to free_cmd().

Signed-off-by: Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
index 205753a..4037406 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
@@ -1113,7 +1113,13 @@ void mlx5_cmd_comp_handler(struct mlx5_core_dev *dev, unsigned long vector)
 
 	for (i = 0; i < (1 << cmd->log_sz); i++) {
 		if (test_bit(i, &vector)) {
+			struct semaphore *sem;
+
 			ent = cmd->ent_arr[i];
+			if (ent->page_queue)
+				sem = &cmd->pages_sem;
+			else
+				sem = &cmd->sem;
 			ktime_get_ts(&ent->ts2);
 			memcpy(ent->out->first.data, ent->lay->out, sizeof(ent->lay->out));
 			dump_command(dev, ent, 0);
@@ -1136,10 +1142,7 @@ void mlx5_cmd_comp_handler(struct mlx5_core_dev *dev, unsigned long vector)
 			} else {
 				complete(&ent->done);
 			}
-			if (ent->page_queue)
-				up(&cmd->pages_sem);
-			else
-				up(&cmd->sem);
+			up(sem);
 		}
 	}
 }
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Re: [patch] mlx5: use after free in mlx5_cmd_comp_handler()

[Eli Cohen]

This race has been spotted and fixed by Moshe Lazer two weeks ago.
Anyways,

Acked by Eli Cohen <eli@mellanox.com>

On Mon, Jul 22, 2013 at 11:02:01AM +0300, Dan Carpenter wrote:
> We can't dereference "ent" after passing it to free_cmd().
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
> index 205753a..4037406 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
> @@ -1113,7 +1113,13 @@ void mlx5_cmd_comp_handler(struct mlx5_core_dev *dev, unsigned long vector)
>  
>  	for (i = 0; i < (1 << cmd->log_sz); i++) {
>  		if (test_bit(i, &vector)) {
> +			struct semaphore *sem;
> +
>  			ent = cmd->ent_arr[i];
> +			if (ent->page_queue)
> +				sem = &cmd->pages_sem;
> +			else
> +				sem = &cmd->sem;
>  			ktime_get_ts(&ent->ts2);
>  			memcpy(ent->out->first.data, ent->lay->out, sizeof(ent->lay->out));
>  			dump_command(dev, ent, 0);
> @@ -1136,10 +1142,7 @@ void mlx5_cmd_comp_handler(struct mlx5_core_dev *dev, unsigned long vector)
>  			} else {
>  				complete(&ent->done);
>  			}
> -			if (ent->page_queue)
> -				up(&cmd->pages_sem);
> -			else
> -				up(&cmd->sem);
> +			up(sem);
>  		}
>  	}
>  }
> --
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Re: [patch] mlx5: use after free in mlx5_cmd_comp_handler()

[David Miller]

From: Eli Cohen <eli-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
Date: Wed, 24 Jul 2013 19:35:44 +0300

> This race has been spotted and fixed by Moshe Lazer two weeks ago.
> Anyways,
> 
> Acked by Eli Cohen <eli-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

Applied.
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