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Revert "Revert "ipv4: fix memory leaks in ip_cmsg_send() callers""

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This reverts commit d7807a9adf.

As mentioned in https://lkml.org/lkml/2021/9/13/1819
5 years old commit 919483096b ("ipv4: fix memory leaks in ip_cmsg_send() callers")
was a correct fix.

  ip_cmsg_send() can loop over multiple cmsghdr()

  If IP_RETOPTS has been successful, but following cmsghdr generates an error,
  we do not free ipc.ok

  If IP_RETOPTS is not successful, we have freed the allocated temporary space,
  not the one currently in ipc.opt.

Sure, code could be refactored, but let's not bring back old bugs.

Fixes: d7807a9adf ("Revert "ipv4: fix memory leaks in ip_cmsg_send() callers"")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2021-09-13 22:18:51 -07:00 committed by David S. Miller
parent 4f884f3962
commit d198b27762
4 changed files with 10 additions and 7 deletions
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2
net/ipv4/ip_sockglue.c
View File

@ -279,7 +279,7 @@ int ip_cmsg_send(struct sock *sk, struct msghdr *msg, struct ipcm_cookie *ipc,
case IP_RETOPTS:
err = cmsg->cmsg_len - sizeof(struct cmsghdr);
/* Our caller is responsible for freeing ipc->opt when err = 0 */
/* Our caller is responsible for freeing ipc->opt */
err = ip_options_get(net, &ipc->opt,
KERNEL_SOCKPTR(CMSG_DATA(cmsg)),
err < 40 ? err : 40);

5
net/ipv4/ping.c
View File

@ -727,9 +727,10 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
if (msg->msg_controllen) {
err = ip_cmsg_send(sk, msg, &ipc, false);
if (unlikely(err))
if (unlikely(err)) {
kfree(ipc.opt);
return err;
}
if (ipc.opt)
free = 1;
}

5
net/ipv4/raw.c
View File

@ -562,9 +562,10 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
if (msg->msg_controllen) {
err = ip_cmsg_send(sk, msg, &ipc, false);
if (unlikely(err))
if (unlikely(err)) {
kfree(ipc.opt);
goto out;
}
if (ipc.opt)
free = 1;
}

5
net/ipv4/udp.c
View File

@ -1122,9 +1122,10 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
if (err > 0)
err = ip_cmsg_send(sk, msg, &ipc,
sk->sk_family == AF_INET6);
if (unlikely(err < 0))
if (unlikely(err < 0)) {
kfree(ipc.opt);
return err;
}
if (ipc.opt)
free = 1;
connected = 0;