6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Rao Shoaib <Rao.Shoaib@xxxxxxxxxx>
[ Upstream commit a6736a0addd60fccc3a3508461d72314cc609772 ]
Read with MSG_PEEK flag loops if the first byte to read is an OOB byte.
commit 22dd70eb2c3d ("af_unix: Don't peek OOB data without MSG_OOB.")
addresses the loop issue but does not address the issue that no data
beyond OOB byte can be read.
>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
>>> c1.send(b'a', MSG_OOB)
1
>>> c1.send(b'b')
1
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
b'b'
>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
>>> c2.setsockopt(SOL_SOCKET, SO_OOBINLINE, 1)
>>> c1.send(b'a', MSG_OOB)
1
>>> c1.send(b'b')
1
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
b'a'
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
b'a'
>>> c2.recv(1, MSG_DONTWAIT)
b'a'
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
b'b'
>>>
Fixes: 314001f0bf92 ("af_unix: Add OOB support")
Signed-off-by: Rao Shoaib <Rao.Shoaib@xxxxxxxxxx>
Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240611084639.2248934-1-Rao.Shoaib@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/unix/af_unix.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2672,18 +2672,18 @@ static struct sk_buff *manage_oob(struct
if (skb == u->oob_skb) {
if (copied) {
skb = NULL;
- } else if (sock_flag(sk, SOCK_URGINLINE)) {
- if (!(flags & MSG_PEEK)) {
+ } else if (!(flags & MSG_PEEK)) {
+ if (sock_flag(sk, SOCK_URGINLINE)) {
WRITE_ONCE(u->oob_skb, NULL);
consume_skb(skb);
+ } else {
+ __skb_unlink(skb, &sk->sk_receive_queue);
+ WRITE_ONCE(u->oob_skb, NULL);
+ unlinked_skb = skb;
+ skb = skb_peek(&sk->sk_receive_queue);
}
- } else if (flags & MSG_PEEK) {
- skb = NULL;
- } else {
- __skb_unlink(skb, &sk->sk_receive_queue);
- WRITE_ONCE(u->oob_skb, NULL);
- unlinked_skb = skb;
- skb = skb_peek(&sk->sk_receive_queue);
+ } else if (!sock_flag(sk, SOCK_URGINLINE)) {
+ skb = skb_peek_next(skb, &sk->sk_receive_queue);
}
}
