strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.
We expect v86d_path to be NUL-terminated based on its use with the
C-string format specifier in printf-likes:
| pr_err("failed to execute %s\n", v86d_path);
and
| return snprintf(buf, PAGE_SIZE, "%s\n", v86d_path);
Let's also opt to pad v86d_path since it may get used in and around
userspace:
| return call_usermodehelper(v86d_path, argv, envp, UMH_WAIT_PROC);
Considering the above, strscpy_pad() is the best replacement as it
guarantees both NUL-termination and NUL-padding on the destination
buffer.
Note that this patch relies on the _new_ 2-argument versions of
strscpy() and strscpy_pad() introduced in Commit e6584c3964f2f ("string:
Allow 2-argument strscpy()").
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@xxxxxxxxxxxxxxx
Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>
---
Note: build-tested only.
Found with: $ rg "strncpy\("
---
drivers/video/fbdev/uvesafb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/uvesafb.c b/drivers/video/fbdev/uvesafb.c
index e1f421e91b4f..8b554fcf1bfb 100644
--- a/drivers/video/fbdev/uvesafb.c
+++ b/drivers/video/fbdev/uvesafb.c
@@ -1867,7 +1867,7 @@ static ssize_t v86d_show(struct device_driver *dev, char *buf)
static ssize_t v86d_store(struct device_driver *dev, const char *buf,
size_t count)
{
- strncpy(v86d_path, buf, PATH_MAX - 1);
+ strscpy_pad(v86d_path, buf);
return count;
}
static DRIVER_ATTR_RW(v86d);
---
base-commit: a4145ce1e7bc247fd6f2846e8699473448717b37
change-id: 20240320-strncpy-drivers-video-fbdev-uvesafb-c-43668c4ef6c8
Best regards,
--
Justin Stitt <justinstitt@xxxxxxxxxx>
