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* [PATCH v5 iwl-next] i40e: Use correct buffer size in i40e_dbg_command_read
@ 2023-12-08  3:19 Kunwu Chan
  2023-12-08 15:00 ` Alexander Lobakin
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Kunwu Chan @ 2023-12-08  3:19 UTC (permalink / raw)
  To: jesse.brandeburg, anthony.l.nguyen, davem, edumazet, kuba, pabeni,
	jeffrey.t.kirsher, shannon.nelson
  Cc: intel-wired-lan, netdev, linux-kernel, Kunwu Chan, Simon Horman,
	Alexander Lobakin, Kunwu Chan

The size of "i40e_dbg_command_buf" is 256, the size of "name"
depends on "IFNAMSIZ", plus a null character and format size,
the total size is more than 256.

Improve readability and maintainability by replacing a hardcoded string
allocation and formatting by the use of the kasprintf() helper.

Fixes: 02e9c290814c ("i40e: debugfs interface")
Suggested-by: Simon Horman <horms@kernel.org>
Suggested-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Suggested-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Cc: Kunwu Chan <kunwu.chan@hotmail.com>
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
---
v2
   - Update the size calculation with IFNAMSIZ and sizeof(i40e_dbg_command_buf)
v3
   - Use kasprintf to improve readability and maintainability
v4
   - Fix memory leak in error path
v5
   - Change the order of labels
---
 .../net/ethernet/intel/i40e/i40e_debugfs.c    | 20 ++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_debugfs.c b/drivers/net/ethernet/intel/i40e/i40e_debugfs.c
index 88240571721a..78a7200211b2 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_debugfs.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_debugfs.c
@@ -72,29 +72,31 @@ static ssize_t i40e_dbg_command_read(struct file *filp, char __user *buffer,
 {
 	struct i40e_pf *pf = filp->private_data;
 	int bytes_not_copied;
-	int buf_size = 256;
 	char *buf;
 	int len;
 
 	/* don't allow partial reads */
 	if (*ppos != 0)
 		return 0;
-	if (count < buf_size)
-		return -ENOSPC;
 
-	buf = kzalloc(buf_size, GFP_KERNEL);
+	buf = kasprintf(GFP_KERNEL, "%s: %s\n",
+			pf->vsi[pf->lan_vsi]->netdev->name,
+			i40e_dbg_command_buf);
 	if (!buf)
 		return -ENOSPC;
 
-	len = snprintf(buf, buf_size, "%s: %s\n",
-		       pf->vsi[pf->lan_vsi]->netdev->name,
-		       i40e_dbg_command_buf);
+	len = strlen(buf) + 1;
+	if (count < len)
+		bytes_not_copied = -ENOSPC;
+	else if (copy_to_user(buffer, buf, len))
+		bytes_not_copied = -EFAULT;
+	else
+		bytes_not_copied = 0;
 
-	bytes_not_copied = copy_to_user(buffer, buf, len);
 	kfree(buf);
 
 	if (bytes_not_copied)
-		return -EFAULT;
+		return bytes_not_copied;
 
 	*ppos = len;
 	return len;
-- 
2.39.2


^ permalink raw reply related	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-12-20 22:12 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-12-08  3:19 [PATCH v5 iwl-next] i40e: Use correct buffer size in i40e_dbg_command_read Kunwu Chan
2023-12-08 15:00 ` Alexander Lobakin
2023-12-09 19:11 ` Simon Horman
2023-12-18  5:54 ` [Intel-wired-lan] " Pucha, HimasekharX Reddy
2023-12-20  1:32   ` Nelson, Shannon
2023-12-20 22:12     ` Tony Nguyen

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