bpf: Check address length before reading address family

KMSAN will complain if valid address length passed to bpf_bind() is
shorter than sizeof("struct sockaddr"->sa_family) bytes.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/filter.c b/net/core/filter.c
index fc92ebc..27e61ff 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4383,6 +4383,8 @@ BPF_CALL_3(bpf_bind, struct bpf_sock_addr_kern *, ctx, struct sockaddr *, addr,
         * Only binding to IP is supported.
         */
        err = -EINVAL;
+       if (addr_len < offsetofend(struct sockaddr, sa_family))
+               return err;
        if (addr->sa_family == AF_INET) {
                if (addr_len < sizeof(struct sockaddr_in))
                        return err;