[PATCH 4.17 023/101] net/mlx5: Fix incorrect raw command length parsing

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alex Vesker <va...@mellanox.com>

[ Upstream commit 603b7bcff824740500ddfa001d7a7168b0b38542 ]

The NULL character was not set correctly for the string containing
the command length, this caused failures reading the output of the
command due to a random length. The fix is to initialize the output
length string.

Fixes: e126ba97dba9 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: Alex Vesker <va...@mellanox.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/cmd.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
@@ -1276,7 +1276,7 @@ static ssize_t outlen_write(struct file
 {
        struct mlx5_core_dev *dev = filp->private_data;
        struct mlx5_cmd_debug *dbg = &dev->cmd.dbg;
-       char outlen_str[8];
+       char outlen_str[8] = {0};
        int outlen;
        void *ptr;
        int err;
@@ -1291,8 +1291,6 @@ static ssize_t outlen_write(struct file
        if (copy_from_user(outlen_str, buf, count))
                return -EFAULT;
 
-       outlen_str[7] = 0;
-
        err = sscanf(outlen_str, "%d", &outlen);
        if (err < 0)
                return err;