ipv6: use READ_ONCE() for inet->hdrincl as in ipv4

[ Upstream commit 59e3e4b526 ]

As it was done in commit 8f659a03a0 ("net: ipv4: fix for a race
condition in raw_sendmsg") and commit 20b50d7997 ("net: ipv4: emulate
READ_ONCE() on ->hdrincl bit-field in raw_sendmsg()") for ipv4, copy the
value of inet->hdrincl in a local variable, to avoid introducing a race
condition in the next commit.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Olivier Matz 2019-06-06 09:15:18 +02:00 committed by Greg Kroah-Hartman
parent 4b83a95655
commit ee6e0cec59

View file

@ -782,6 +782,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
struct sockcm_cookie sockc;
struct ipcm6_cookie ipc6;
int addr_len = msg->msg_namelen;
int hdrincl;
u16 proto;
int err;
@ -795,6 +796,13 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
if (msg->msg_flags & MSG_OOB)
return -EOPNOTSUPP;
/* hdrincl should be READ_ONCE(inet->hdrincl)
* but READ_ONCE() doesn't work with bit fields.
* Doing this indirectly yields the same result.
*/
hdrincl = inet->hdrincl;
hdrincl = READ_ONCE(hdrincl);
/*
* Get and verify the address.
*/
@ -913,7 +921,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
fl6.flowi6_oif = np->ucast_oif;
security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
if (inet->hdrincl)
if (hdrincl)
fl6.flowi6_flags |= FLOWI_FLAG_KNOWN_NH;
if (ipc6.tclass < 0)
@ -936,7 +944,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
goto do_confirm;
back_from_confirm:
if (inet->hdrincl)
if (hdrincl)
err = rawv6_send_hdrinc(sk, msg, len, &fl6, &dst, msg->msg_flags);
else {
ipc6.opt = opt;