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

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commit 59e3e4b52663a9d97efbce7307f62e4bc5c9ce91 upstream.

As it was done in commit 8f659a03a0ba ("net: ipv4: fix for a race
condition in raw_sendmsg") and commit 20b50d79974e ("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 d44ee5417e
commit 9e68a660e9
1 changed files with 10 additions and 2 deletions
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12
net/ipv6/raw.c
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@ -757,6 +757,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
int hlimit = -1;
int tclass = -1;
int dontfrag = -1;
int hdrincl;
u16 proto;
int err;
@ -770,6 +771,13 @@ 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.
*/
@ -878,7 +886,7 @@ 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;
dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
@ -899,7 +907,7 @@ 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 {
lock_sock(sk);