2024-05-28 13:33:48

by Arnd Bergmann

Subject: [PATCH] drm/xe: replace format-less snprintf() with strscpy()

From: Arnd Bergmann <[email protected]>

Using snprintf() with a format string from task->comm is a bit
dangerous since the string may be controlled by unprivileged
userspace:

drivers/gpu/drm/xe/xe_devcoredump.c: In function 'devcoredump_snapshot':
drivers/gpu/drm/xe/xe_devcoredump.c:184:9: error: format not a string literal and no format arguments [-Werror=format-security]
184 | snprintf(ss->process_name, sizeof(ss->process_name), process_name);
| ^~~~~~~~

In this case there is no reason for an snprintf(), so use a simpler
string copy.

Fixes: b10d0c5e9df7 ("drm/xe: Add process name to devcoredump")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/gpu/drm/xe/xe_devcoredump.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
index 1643d44f8bc4..1973bfaece40 100644
--- a/drivers/gpu/drm/xe/xe_devcoredump.c
+++ b/drivers/gpu/drm/xe/xe_devcoredump.c
@@ -181,7 +181,7 @@ static void devcoredump_snapshot(struct xe_devcoredump *coredump,
if (task)
process_name = task->comm;
}
- snprintf(ss->process_name, sizeof(ss->process_name), process_name);
+ strscpy(ss->process_name, process_name);
if (task)
put_task_struct(task);

--
2.39.2

2024-05-28 17:50:49

by Thomas Hellström

Subject: Re: [PATCH] drm/xe: replace format-less snprintf() with strscpy()

On Tue, 2024-05-28 at 15:32 +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> Using snprintf() with a format string from task->comm is a bit
> dangerous since the string may be controlled by unprivileged
> userspace:
>
> drivers/gpu/drm/xe/xe_devcoredump.c: In function
> 'devcoredump_snapshot':
> drivers/gpu/drm/xe/xe_devcoredump.c:184:9: error: format not a string
> literal and no format arguments [-Werror=format-security]
>   184 |         snprintf(ss->process_name, sizeof(ss->process_name),
> process_name);
>       |         ^~~~~~~~
>
> In this case there is no reason for an snprintf(), so use a simpler
> string copy.
>
> Fixes: b10d0c5e9df7 ("drm/xe: Add process name to devcoredump")
> Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Thomas Hellström <[email protected]>

Thanks,

Will pick up and apply as soon as our CI is fit for fight.
/Thomas



> ---
>  drivers/gpu/drm/xe/xe_devcoredump.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c
> b/drivers/gpu/drm/xe/xe_devcoredump.c
> index 1643d44f8bc4..1973bfaece40 100644
> --- a/drivers/gpu/drm/xe/xe_devcoredump.c
> +++ b/drivers/gpu/drm/xe/xe_devcoredump.c
> @@ -181,7 +181,7 @@ static void devcoredump_snapshot(struct
> xe_devcoredump *coredump,
>   if (task)
>   process_name = task->comm;
>   }
> - snprintf(ss->process_name, sizeof(ss->process_name),
> process_name);
> + strscpy(ss->process_name, process_name);
>   if (task)
>   put_task_struct(task);
>