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alistair23-linux
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ipv6: use READ_ONCE() for inet->hdrincl as in ipv4 

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>
hifive-unleashed-5.2
Olivier Matz 2019-06-06 09:15:18 +02:00 committed by David S. Miller
parent 4970b42d5c
commit 59e3e4b526
1 changed files with 10 additions and 2 deletions
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12
net/ipv6/raw.c
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@ -783,6 +783,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
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, 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.
*/
@ -908,7 +916,7 @@ 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)
@ -931,7 +939,7 @@ 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, &ipc6.sockc);
else {