diff options
| author | Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru> | 2024-02-14 09:01:50 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-02-15 07:50:32 -0800 |
| commit | dc34ebd5c018b0edf47f39d11083ad8312733034 (patch) | |
| tree | 76d47d7e98d065898c8c12e55202373aae6a7e5b /drivers | |
| parent | 4e45170d9acc2d5ae8f545bf3f2f67504a361338 (diff) | |
pppoe: Fix memory leak in pppoe_sendmsg()
syzbot reports a memory leak in pppoe_sendmsg [1].
The problem is in the pppoe_recvmsg() function that handles errors
in the wrong order. For the skb_recv_datagram() function, check
the pointer to skb for NULL first, and then check the 'error' variable,
because the skb_recv_datagram() function can set 'error'
to -EAGAIN in a loop but return a correct pointer to socket buffer
after a number of attempts, though 'error' remains set to -EAGAIN.
skb_recv_datagram
__skb_recv_datagram // Loop. if (err == -EAGAIN) then
// go to the next loop iteration
__skb_try_recv_datagram // if (skb != NULL) then return 'skb'
// else if a signal is received then
// return -EAGAIN
Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with Syzkaller.
Link: https://syzkaller.appspot.com/bug?extid=6bdfd184eac7709e5cc9 [1]
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+6bdfd184eac7709e5cc9@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6bdfd184eac7709e5cc9
Signed-off-by: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Link: https://lore.kernel.org/r/20240214085814.3894917-1-Ilia.Gavrilov@infotecs.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/ppp/pppoe.c | 23 |
1 files changed, 9 insertions, 14 deletions
diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c index 8e7238e97d0a..2ea4f4890d23 100644 --- a/drivers/net/ppp/pppoe.c +++ b/drivers/net/ppp/pppoe.c @@ -1007,26 +1007,21 @@ static int pppoe_recvmsg(struct socket *sock, struct msghdr *m, struct sk_buff *skb; int error = 0; - if (sk->sk_state & PPPOX_BOUND) { - error = -EIO; - goto end; - } + if (sk->sk_state & PPPOX_BOUND) + return -EIO; skb = skb_recv_datagram(sk, flags, &error); - if (error < 0) - goto end; + if (!skb) + return error; - if (skb) { - total_len = min_t(size_t, total_len, skb->len); - error = skb_copy_datagram_msg(skb, 0, m, total_len); - if (error == 0) { - consume_skb(skb); - return total_len; - } + total_len = min_t(size_t, total_len, skb->len); + error = skb_copy_datagram_msg(skb, 0, m, total_len); + if (error == 0) { + consume_skb(skb); + return total_len; } kfree_skb(skb); -end: return error; } |