From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
[ Upstream commit b12e924a2f5b960373459c8f8a514f887adf5cac ]
syzbot is hitting skb_assert_len() warning at __dev_queue_xmit() [1], for PF_IEEE802154 socket's zero-sized raw_sendmsg() request is hitting __dev_queue_xmit() with skb->len == 0.
Since PF_IEEE802154 socket's zero-sized raw_sendmsg() request was able to return 0, don't call __dev_queue_xmit() if packet length is 0.
---------- #include <sys/socket.h> #include <netinet/in.h>
int main(int argc, char *argv[]) { struct sockaddr_in addr = { .sin_family = AF_INET, .sin_addr.s_addr = htonl(INADDR_LOOPBACK) }; struct iovec iov = { }; struct msghdr hdr = { .msg_name = &addr, .msg_namelen = sizeof(addr), .msg_iov = &iov, .msg_iovlen = 1 }; sendmsg(socket(PF_IEEE802154, SOCK_RAW, 0), &hdr, 0); return 0; } ----------
Note that this might be a sign that commit fd1894224407c484 ("bpf: Don't redirect packets with invalid pkt_len") should be reverted, for skb->len == 0 was acceptable for at least PF_IEEE802154 socket.
Link: https://syzkaller.appspot.com/bug?extid=5ea725c25d06fb9114c4 [1] Reported-by: syzbot syzbot+5ea725c25d06fb9114c4@syzkaller.appspotmail.com Fixes: fd1894224407c484 ("bpf: Don't redirect packets with invalid pkt_len") Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Alexander Aring aahringo@redhat.com Link: https://lore.kernel.org/r/20221005014750.3685555-2-aahringo@redhat.com Signed-off-by: Stefan Schmidt stefan@datenfreihafen.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/ieee802154/socket.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/ieee802154/socket.c b/net/ieee802154/socket.c index 7889e1ef7fad..6e55fae4c686 100644 --- a/net/ieee802154/socket.c +++ b/net/ieee802154/socket.c @@ -272,6 +272,10 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) err = -EMSGSIZE; goto out_dev; } + if (!size) { + err = 0; + goto out_dev; + }
hlen = LL_RESERVED_SPACE(dev); tlen = dev->needed_tailroom;