[PATCH] cxl: Fix possible null pointer dereference in read_handle()

[PATCH] cxl: Fix possible null pointer dereference in read_handle()

[Ma Ke]

In read_handle() of_get_address() may return NULL which is later
dereferenced. Fix this bug by adding NULL check.

Cc: stable@vger.kernel.org
Fixes: 14baf4d9c739 ("cxl: Add guest-specific code")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
---
 drivers/misc/cxl/of.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/cxl/of.c b/drivers/misc/cxl/of.c
index bcc005dff1c0..d8dbb3723951 100644
--- a/drivers/misc/cxl/of.c
+++ b/drivers/misc/cxl/of.c
@@ -58,7 +58,7 @@ static int read_handle(struct device_node *np, u64 *handle)
 
 	/* Get address and size of the node */
 	prop = of_get_address(np, 0, &size, NULL);
-	if (size)
+	if (!prop || size)
 		return -EINVAL;
 
 	/* Helper to read a big number; size is in cells (not bytes) */
-- 
2.25.1

Re: [PATCH] cxl: Fix possible null pointer dereference in read_handle()

[Greg KH]

On Tue, Jul 09, 2024 at 09:17:54PM +0800, Ma Ke wrote:
> In read_handle() of_get_address() may return NULL which is later
> dereferenced. Fix this bug by adding NULL check.
> 
> Cc: stable@vger.kernel.org
> Fixes: 14baf4d9c739 ("cxl: Add guest-specific code")
> Signed-off-by: Ma Ke <make24@iscas.ac.cn>
> ---
>  drivers/misc/cxl/of.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/misc/cxl/of.c b/drivers/misc/cxl/of.c
> index bcc005dff1c0..d8dbb3723951 100644
> --- a/drivers/misc/cxl/of.c
> +++ b/drivers/misc/cxl/of.c
> @@ -58,7 +58,7 @@ static int read_handle(struct device_node *np, u64 *handle)
>  
>  	/* Get address and size of the node */
>  	prop = of_get_address(np, 0, &size, NULL);
> -	if (size)
> +	if (!prop || size)
>  		return -EINVAL;

How was this issue found?

thanks,

greg k-h

Re: [PATCH] cxl: Fix possible null pointer dereference in read_handle()

[Markus Elfring]

…
> Signed-off-by: Ma Ke <make24@iscas.ac.cn>

Under which circumstances will this information be corrected anyhow?

The usage of mailing list addresses is probably undesirable for
the Developer's Certificate of Origin, isn't it?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.10-rc7#n398

Regards,
Markus