[PATCH] CIFS: Fix a potencially linear read overflow

Paulo Alcantara pc at cjr.nz
Wed Aug 18 00:28:40 UTC 2021

Len Baker <len.baker at gmx.com> writes:

> strlcpy() reads the entire source buffer first. This read may exceed the
> destination size limit. This is both inefficient and can lead to linear
> read overflows if a source string is not NUL-terminated.
> Also, the strnlen() call does not avoid the read overflow in the strlcpy
> function when a not NUL-terminated string is passed.
> So, replace this block by a call to kstrndup() that avoids this type of
> overflow and does the same.
> Fixes: 066ce6899484d ("cifs: rename cifs_strlcpy_to_host and make it use new functions")
> Signed-off-by: Len Baker <len.baker at gmx.com>
> ---
>  fs/cifs/cifs_unicode.c | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)

Reviewed-by: Paulo Alcantara (SUSE) <pc at cjr.nz>

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