This is a note to let you know that I've just added the patch titled
net: ipv4: fix for a race condition in raw_sendmsg
to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: net-ipv4-fix-for-a-race-condition-in-raw_sendmsg.patch and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Sun Dec 31 11:31:10 CET 2017
From: Mohamed Ghannam simo.ghannam@gmail.com Date: Sun, 10 Dec 2017 03:50:58 +0000 Subject: net: ipv4: fix for a race condition in raw_sendmsg
From: Mohamed Ghannam simo.ghannam@gmail.com
[ Upstream commit 8f659a03a0ba9289b9aeb9b4470e6fb263d6f483 ]
inet->hdrincl is racy, and could lead to uninitialized stack pointer usage, so its value should be read only once.
Fixes: c008ba5bdc9f ("ipv4: Avoid reading user iov twice after raw_probe_proto_opt") Signed-off-by: Mohamed Ghannam simo.ghannam@gmail.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/raw.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)
--- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -483,11 +483,16 @@ static int raw_sendmsg(struct kiocb *ioc u8 tos; int err; struct ip_options_data opt_copy; + int hdrincl;
err = -EMSGSIZE; if (len > 0xFFFF) goto out;
+ /* hdrincl should be READ_ONCE(inet->hdrincl) + * but READ_ONCE() doesn't work with bit fields + */ + hdrincl = inet->hdrincl; /* * Check the flags. */ @@ -560,7 +565,7 @@ static int raw_sendmsg(struct kiocb *ioc /* Linux does not mangle headers on raw sockets, * so that IP options + IP_HDRINCL is non-sense. */ - if (inet->hdrincl) + if (hdrincl) goto done; if (ipc.opt->opt.srr) { if (!daddr) @@ -582,12 +587,12 @@ static int raw_sendmsg(struct kiocb *ioc
flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, - inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, + hdrincl ? IPPROTO_RAW : sk->sk_protocol, inet_sk_flowi_flags(sk) | - (inet->hdrincl ? FLOWI_FLAG_KNOWN_NH : 0), + (hdrincl ? FLOWI_FLAG_KNOWN_NH : 0), daddr, saddr, 0, 0);
- if (!inet->hdrincl) { + if (!hdrincl) { err = raw_probe_proto_opt(&fl4, msg); if (err) goto done; @@ -609,7 +614,7 @@ static int raw_sendmsg(struct kiocb *ioc goto do_confirm; back_from_confirm:
- if (inet->hdrincl) + if (hdrincl) err = raw_send_hdrinc(sk, &fl4, msg->msg_iov, len, &rt, msg->msg_flags);
Patches currently in stable-queue which might be from simo.ghannam@gmail.com are
queue-3.18/net-ipv4-fix-for-a-race-condition-in-raw_sendmsg.patch