net: fix rtnh_ok()

syzbot reported :

BUG: KMSAN: uninit-value in rtnh_ok include/net/nexthop.h:11 [inline]
BUG: KMSAN: uninit-value in fib_count_nexthops net/ipv4/fib_semantics.c:469 [inline]
BUG: KMSAN: uninit-value in fib_create_info+0x554/0x8d20 net/ipv4/fib_semantics.c:1091

@remaining is an integer, coming from user space.
If it is negative we want rtnh_ok() to return false.

Fixes: 4e902c5741 ("[IPv4]: FIB configuration using struct fib_config")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2018-04-07 13:42:38 -07:00 committed by David S. Miller
parent 6091f09c2f
commit b1993a2de1
1 changed files with 1 additions and 1 deletions

View File

@ -7,7 +7,7 @@
static inline int rtnh_ok(const struct rtnexthop *rtnh, int remaining)
{
return remaining >= sizeof(*rtnh) &&
return remaining >= (int)sizeof(*rtnh) &&
rtnh->rtnh_len >= sizeof(*rtnh) &&
rtnh->rtnh_len <= remaining;
}