Re: [PATCH] mount.cifs: fix buffer overrun in set_password

Steve French
2026-04-01T02:03:27Z

Good catch. Fixed the RB tag

On Tue, Mar 31, 2026 at 7:58 PM David Disseldorp <ddiss@suse.de> wrote:
>
> On Tue, 31 Mar 2026 18:56:05 -0500, Steve French wrote:
>
> > added RB from Henrique and updated
> > git.samba.org/data/git/cifs-utils.git and
> > https://github.com/smfrench/smb3-utils for-next
>
> Thanks Steve. FWIW, the reviewed-by tag has an incorrect email address:
> Reviewed-by: Henrique Carvalho <[2]henrique.carvalho@suse.com>
> Should be
> Reviewed-by: Henrique Carvalho <henrique.carvalho@suse.com>
>
> I'll close the corresponding PR at
> https://github.com/smfrench/smb3-utils/pull/16
>
> Cheers, David
>
> > On Mon, Mar 30, 2026 at 7:10 PM David Disseldorp <ddiss@suse.de> wrote:
> > >
> > > The existing (j > pass_length) check is insufficient to avoid dst buffer
> > > overrun into the start of the adjacent struct parsed_mount_info field.
> > > Check for overrun before writing to dst, and account for comma-expansion
> > > and null-termination.
> > >
> > > Bug: https://bugzilla.samba.org/show_bug.cgi?id=16044
> > >
> > > Reported-by: Bruno Bierbaumer <bruno@bierbaumer.net>
> > > Signed-off-by: David Disseldorp <ddiss@suse.de>
> > > ---
> > > mount.cifs.c | 8 ++++----
> > > 1 file changed, 4 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/mount.cifs.c b/mount.cifs.c
> > > index 1923913..d41ca6a 100644
> > > --- a/mount.cifs.c
> > > +++ b/mount.cifs.c
> > > @@ -350,13 +350,13 @@ set_password(struct parsed_mount_info *parsed_info, const char *src,
> > > unsigned int i = 0, j = 0;
> > >
> > > while (src[i]) {
> > > - if (src[i] == ',')
> > > - dst[j++] = ',';
> > > - dst[j++] = src[i++];
> > > - if (j > pass_length) {
> > > + if (j + 2 >= pass_length) {
> > > fprintf(stderr, "Converted password too long!\n");
> > > return EX_USAGE;
> > > }
> > > + if (src[i] == ',')
> > > + dst[j++] = ',';
> > > + dst[j++] = src[i++];
> > > }
> > > dst[j] = '\0';
> > > if (is_pass2)
> > > --
> > > 2.51.0
> > >
> >
> >
>

--
Thanks,

Steve