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Message-Id: <20231205095844.2532859-1-chentao@kylinos.cn>
Date: Tue, 5 Dec 2023 17:58:44 +0800
From: Kunwu Chan <chentao@...inos.cn>
To: jesse.brandeburg@...el.com,
anthony.l.nguyen@...el.com,
davem@...emloft.net,
edumazet@...gle.com,
kuba@...nel.org,
pabeni@...hat.com,
jeffrey.t.kirsher@...el.com,
shannon.nelson@....com
Cc: kunwu.chan@...mail.com,
netdev@...r.kernel.org,
linux-kernel@...r.kernel.org,
Kunwu Chan <chentao@...inos.cn>,
Simon Horman <horms@...nel.org>,
Alexander Lobakin <aleksander.lobakin@...el.com>
Subject: [PATCH v4 iwl-next] i40e: Use correct buffer size in i40e_dbg_command_read
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")
Signed-off-by: Kunwu Chan <chentao@...inos.cn>
Suggested-by: Simon Horman <horms@...nel.org>
Suggested-by: Alexander Lobakin <aleksander.lobakin@...el.com>
---
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
---
.../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;
--
2.34.1
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