| Message ID | 1404927082-8647-1-git-send-email-blp@nicira.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Ben Pfaff <blp@nicira.com> Date: Wed, 9 Jul 2014 10:31:22 -0700 > netlink_dump() returns a negative errno value on error. Until now, > netlink_recvmsg() directly recorded that negative value in sk->sk_err, but > that's wrong since sk_err takes positive errno values. (This manifests as > userspace receiving a positive return value from the recv() system call, > falsely indicating success.) This bug was introduced in the commit that > started checking the netlink_dump() return value, commit b44d211 (netlink: > handle errors from netlink_dump()). > > Multithreaded Netlink dumps are one way to trigger this behavior in > practice, as described in the commit message for the userspace workaround > posted here: > http://openvswitch.org/pipermail/dev/2014-June/042339.html > > This commit also fixes the same bug in netlink_poll(), introduced in commit > cd1df525d (netlink: add flow control for memory mapped I/O). > > Signed-off-by: Ben Pfaff <blp@nicira.com> > --- > v1->v2: Fix same bug in another place, as requested by Dave Miller. Applied, thank you. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 15c731f..e6fac7e 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -636,7 +636,7 @@ static unsigned int netlink_poll(struct file *file, struct socket *sock, while (nlk->cb_running && netlink_dump_space(nlk)) { err = netlink_dump(sk); if (err < 0) { - sk->sk_err = err; + sk->sk_err = -err; sk->sk_error_report(sk); break; } @@ -2483,7 +2483,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock, atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { ret = netlink_dump(sk); if (ret) { - sk->sk_err = ret; + sk->sk_err = -ret; sk->sk_error_report(sk); } }
netlink_dump() returns a negative errno value on error. Until now, netlink_recvmsg() directly recorded that negative value in sk->sk_err, but that's wrong since sk_err takes positive errno values. (This manifests as userspace receiving a positive return value from the recv() system call, falsely indicating success.) This bug was introduced in the commit that started checking the netlink_dump() return value, commit b44d211 (netlink: handle errors from netlink_dump()). Multithreaded Netlink dumps are one way to trigger this behavior in practice, as described in the commit message for the userspace workaround posted here: http://openvswitch.org/pipermail/dev/2014-June/042339.html This commit also fixes the same bug in netlink_poll(), introduced in commit cd1df525d (netlink: add flow control for memory mapped I/O). Signed-off-by: Ben Pfaff <blp@nicira.com> --- v1->v2: Fix same bug in another place, as requested by Dave Miller. net/netlink/af_netlink.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)