Thomas Graf 57c374d382 netlink: Don't reorder loads/stores before marking mmap netlink frame as available ... [ Upstream commit a18e6a186f53af06937a2c268c72443336f4ab56 ] Each mmap Netlink frame contains a status field which indicates whether the frame is unused, reserved, contains data or needs to be skipped. Both loads and stores may not be reordeded and must complete before the status field is changed and another CPU might pick up the frame for use. Use an smp_mb() to cover needs of both types of callers to netlink_set_status(), callers which have been reading data frame from the frame, and callers which have been filling or releasing and thus writing to the frame. - Example code path requiring a smp_rmb(): memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len); netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED); - Example code path requiring a smp_wmb(): hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid); hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid); netlink_frame_flush_dcache(hdr); netlink_set_status(hdr, NL_MMAP_STATUS_VALID); Fixes: f9c228 ("netlink: implement memory mapped recvmsg()") Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2015-01-27 07:52:30 -08:00
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af_netlink.c	netlink: Don't reorder loads/stores before marking mmap netlink frame as available	2015-01-27 07:52:30 -08:00
af_netlink.h	netlink: mmaped netlink: ring setup	2013-04-19 14:57:57 -04:00
diag.c	netlink: Fix build with mmap disabled.	2013-04-23 15:39:03 -04:00
genetlink.c	net: Use netlink_ns_capable to verify the permisions of netlink messages	2014-06-26 15:12:37 -04:00
Kconfig	netlink: kconfig: move mmap i/o into netlink kconfig	2013-05-01 15:02:42 -04:00
Makefile	netlink: Diag core and basic socket info dumping (v2)	2013-03-21 12:38:03 -04:00