[IPV6] fix ipv6_getsockopt_sticky copy_to_user leak

User supplied len < 0 can cause leak of kernel memory.
Use unsigned compare instead.

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index b82333b9228fdb6e405351cfe32ad6f431cc62a6..f5f9582a8d39554c120ed147ddc9f71105d6a889 100644 (file)
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -804,7 +804,7 @@ static int ipv6_getsockopt_sticky(struct sock *sk, struct ipv6_txoptions *opt,
                return 0;
        hdr = opt->hopopt;
 
-       len = min_t(int, len, ipv6_optlen(hdr));
+       len = min_t(unsigned int, len, ipv6_optlen(hdr));
        if (copy_to_user(optval, hdr, ipv6_optlen(hdr)))
                return -EFAULT;
        return len;