net: sctp: fix bug in sctp_poll for SOCK_SELECT_ERR_QUEUE
authorDaniel Borkmann <dborkman@redhat.com>
Sat, 7 Sep 2013 14:44:59 +0000 (16:44 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 13 Oct 2013 23:08:28 +0000 (16:08 -0700)
commit8b1ada497191ab2be429c74817a8de63f9aa2bf6
treef4179e473031db3008dd01f987c53af4ef93dabb
parent45d268c6b87c0c80fda9960a8b850ee0e82b71dc
net: sctp: fix bug in sctp_poll for SOCK_SELECT_ERR_QUEUE

[ Upstream commit a0fb05d1aef0f5df936f80b726d1b3bfd4275f95 ]

If we do not add braces around ...

  mask |= POLLERR |
          sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0;

... then this condition always evaluates to true as POLLERR is
defined as 8 and binary or'd with whatever result comes out of
sock_flag(). Hence instead of (X | Y) ? A : B, transform it into
X | (Y ? A : B). Unfortunatelty, commit 8facd5fb73 ("net: fix
smatch warnings inside datagram_poll") forgot about SCTP. :-(

Introduced by 7d4c04fc170 ("net: add option to enable error queue
packets waking select").

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/sctp/socket.c