From: Olivier Matz olivier.matz@6wind.com
[ Upstream commit 59e3e4b52663a9d97efbce7307f62e4bc5c9ce91 ]
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 --- net/ipv6/raw.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
--- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -783,6 +783,7 @@ static int rawv6_sendmsg(struct sock *sk struct flowi6 fl6; struct ipcm6_cookie ipc6; int addr_len = msg->msg_namelen; + int hdrincl; u16 proto; int err;
@@ -796,6 +797,13 @@ static int rawv6_sendmsg(struct sock *sk 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. */ @@ -908,7 +916,7 @@ static int rawv6_sendmsg(struct sock *sk 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) @@ -931,7 +939,7 @@ static int rawv6_sendmsg(struct sock *sk goto do_confirm;
back_from_confirm: - if (inet->hdrincl) + if (hdrincl) err = rawv6_send_hdrinc(sk, msg, len, &fl6, &dst, msg->msg_flags, &ipc6.sockc); else {