| From foo@baz Sun 09 Jun 2019 09:24:16 AM CEST |
| From: Olivier Matz <olivier.matz@6wind.com> |
| Date: Thu, 6 Jun 2019 09:15:18 +0200 |
| Subject: ipv6: use READ_ONCE() for inet->hdrincl as in ipv4 |
| |
| 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 { |