[v2] drivers/misc: Add NULL check in aspeed_lpc_enable_snoop

[PATCH v2] drivers/misc: Add NULL check in aspeed_lpc_enable_snoop

Posted by Henry Martin 8 months, 3 weeks ago

devm_kasprintf() returns NULL if memory allocation fails. Currently,
aspeed_lpc_enable_snoop() does not check for this case, leading to a NULL
pointer dereference.

Add NULL check after devm_kasprintf() to prevent this issue.

Fixes: 3772e5da4454 ("drivers/misc: Aspeed LPC snoop output using misc chardev")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
---
V1 -> V2: Removed blank line between tags.

Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
---
 drivers/soc/aspeed/aspeed-lpc-snoop.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c b/drivers/soc/aspeed/aspeed-lpc-snoop.c
index 9ab5ba9cf1d6..376b3a910797 100644
--- a/drivers/soc/aspeed/aspeed-lpc-snoop.c
+++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
@@ -200,6 +200,8 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 	lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
 	lpc_snoop->chan[channel].miscdev.name =
 		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
+	if (!lpc_snoop->chan[channel].miscdev.name)
+		return -ENOMEM;
 	lpc_snoop->chan[channel].miscdev.fops = &snoop_fops;
 	lpc_snoop->chan[channel].miscdev.parent = dev;
 	rc = misc_register(&lpc_snoop->chan[channel].miscdev);
-- 
2.34.1

Re: [PATCH v2] drivers/misc: Add NULL check in aspeed_lpc_enable_snoop

Posted by Markus Elfring 8 months, 3 weeks ago

> devm_kasprintf() returns NULL if memory allocation fails. Currently,
…
                 call?                               failed?


An other subsystem specification might be more desirable.
https://web.git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/log/drivers/soc/aspeed/aspeed-lpc-snoop.c?h=next-20250331


…
> +++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
> @@ -200,6 +200,8 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
>  	lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
>  	lpc_snoop->chan[channel].miscdev.name =
>  		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
> +	if (!lpc_snoop->chan[channel].miscdev.name)
> +		return -ENOMEM;
…

Can a blank line be preferred after such a statement?


* May the array access be simplified another bit here?
* How do you think about to store a pointer to a corresponding data structure member
  in an additional local variable?


Regards,
Markus