[PATCH] CIFS: Fix a potencially linear read overflow

[Steve French]

tentatively merged into cifs-2.6.git for-next pending testing

On Tue, Aug 17, 2021 at 7:29 PM Paulo Alcantara <pc at cjr.nz> wrote:
>
> 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>



-- 
Thanks,

Steve