mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

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: 1da177e4c3 ("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>
This commit is contained in:
Gavrilov Ilia 2024-02-14 09:01:50 +00:00 committed by Jakub Kicinski
parent 4e45170d9a
commit dc34ebd5c0
1 changed files with 9 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
drivers/net/ppp/pppoe.c
View File

@ -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;
}