6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Rao Shoaib Rao.Shoaib@oracle.com
[ 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@oracle.com Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://lore.kernel.org/r/20240611084639.2248934-1-Rao.Shoaib@oracle.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 @@ -2596,18 +2596,18 @@ 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); } }