On Fri, Apr 12, 2019 at 08:21:26PM +0900, Tetsuo Handa wrote:
> On 2019/04/12 20:12, Neil Horman wrote:
> > On Fri, Apr 12, 2019 at 07:53:10PM +0900, Tetsuo Handa wrote:
> >> KMSAN will complain if valid address length passed to connect() is shorter
> >> than sizeof("struct sockaddr"->sa_family) bytes.
> >>
> >> Signed-off-by: Tetsuo Handa <[email protected]>
> >> ---
> >> net/sctp/socket.c | 3 ++-
> >> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> >> index 9874e60c9b0d..4583fa914e62 100644
> >> --- a/net/sctp/socket.c
> >> +++ b/net/sctp/socket.c
> >> @@ -4847,7 +4847,8 @@ static int sctp_connect(struct sock *sk, struct
> >> sockaddr *addr,
> >> }
> >>
> >> /* Validate addr_len before calling common connect/connectx routine. */
> >> - af = sctp_get_af_specific(addr->sa_family);
> >> + af = addr_len < offsetofend(struct sockaddr, sa_family) ? NULL :
> >> + sctp_get_af_specific(addr->sa_family);
> > I don't see anything wrong with the patch per se, but sctp_get_af_specific
> > will
> > always return a value that is greater than offsetofend(struct sockaddr,
> > sa_family). So while this patch doesn't do anything wrong, it seems your
> > fixing
> > an erroneous KMSAN warning in the SCTP code. Shouldn't KMSAN just be made
> > to
> > not complain if the address length is valid?
>
> KMSAN does not complain if the address length is valid. KMSAN complains
> at addr->sa_family if the address length passed to connect() is either 0 or 1.
> Thus, we need to verify addr_len >= 2 before accessing addr->sa_family.
>
Ah, ok, then with the subject change you note in your other email
Acked-by: Neil Horman <[email protected]>
> >
> > Neil
> >
> >> if (!af || addr_len < af->sockaddr_len) {
> >> err = -EINVAL;
> >> } else {
> >> --
> >> 2.16.5
> >>
> >>
> >
>
>
