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authorKuniyuki Iwashima2024-04-10 10:10:16 -0700
committerJakub Kicinski2024-04-12 19:05:49 -0700
commit22dd70eb2c3d754862964377a75abafd3167346b (patch)
treefd087e4e3dd8a3cc3c7dd8178f9d8b313ce312f8 /net
parent283454c8a123072e5c386a5a2b5fc576aa455b6f (diff)
af_unix: Don't peek OOB data without MSG_OOB.
Currently, we can read OOB data without MSG_OOB by using MSG_PEEK when OOB data is sitting on the front row, which is apparently wrong. >>> from socket import * >>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM) >>> c1.send(b'a', MSG_OOB) 1 >>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT) b'a' If manage_oob() is called when no data has been copied, we only check if the socket enables SO_OOBINLINE or MSG_PEEK is not used. Otherwise, the skb is returned as is. However, here we should return NULL if MSG_PEEK is set and no data has been copied. Also, in such a case, we should not jump to the redo label because we will be caught in the loop and hog the CPU until normal data comes in. Then, we need to handle skb == NULL case with the if-clause below the manage_oob() block. With this patch: >>> from socket import * >>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM) >>> c1.send(b'a', MSG_OOB) 1 >>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT) Traceback (most recent call last): File "<stdin>", line 1, in <module> BlockingIOError: [Errno 11] Resource temporarily unavailable Fixes: 314001f0bf92 ("af_unix: Add OOB support") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20240410171016.7621-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/unix/af_unix.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index f297320438bf..9a6ad5974dff 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2663,7 +2663,9 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
WRITE_ONCE(u->oob_skb, NULL);
consume_skb(skb);
}
- } else if (!(flags & MSG_PEEK)) {
+ } else if (flags & MSG_PEEK) {
+ skb = NULL;
+ } else {
skb_unlink(skb, &sk->sk_receive_queue);
WRITE_ONCE(u->oob_skb, NULL);
if (!WARN_ON_ONCE(skb_unref(skb)))
@@ -2745,11 +2747,9 @@ again:
#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
if (skb) {
skb = manage_oob(skb, sk, flags, copied);
- if (!skb) {
+ if (!skb && copied) {
unix_state_unlock(sk);
- if (copied)
- break;
- goto redo;
+ break;
}
}
#endif