[PATCH] can: isotp: restore accidentally removed MSG_PEEK feature

* [PATCH] can: isotp: restore accidentally removed MSG_PEEK feature
@ 2022-03-28 11:36 Oliver Hartkopp
  2022-03-28 12:22 ` Marc Kleine-Budde
  0 siblings, 1 reply; 4+ messages in thread
From: Oliver Hartkopp @ 2022-03-28 11:36 UTC (permalink / raw)
  To: linux-can; +Cc: Oliver Hartkopp, Derek Will

In commit 42bf50a1795a ("can: isotp: support MSG_TRUNC flag when reading
from socket") a new check for recvmsg flags has been introduced that
only checked for the flags that are handled in isotp_recvmsg() itself.

This accidentally removed the MSG_PEEK feature flag which is processed
later in the call chain in __skb_try_recv_from_queue().

Add MSG_PEEK to the set of valid flags to restore the feature.

Fixes: 42bf50a1795a ("can: isotp: support MSG_TRUNC flag when reading from socket")
Link: https://github.com/linux-can/can-utils/issues/347#issuecomment-1079554254
From: Derek Will <derekrobertwill@gmail.com>
Tested-by: Derek Will <derekrobertwill@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 net/can/isotp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/can/isotp.c b/net/can/isotp.c
index f6f8ba1f816d..bafb0fb5f0e0 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1048,11 +1048,11 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 	struct sk_buff *skb;
 	struct isotp_sock *so = isotp_sk(sk);
 	int noblock = flags & MSG_DONTWAIT;
 	int ret = 0;
 
-	if (flags & ~(MSG_DONTWAIT | MSG_TRUNC))
+	if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK))
 		return -EINVAL;
 
 	if (!so->bound)
 		return -EADDRNOTAVAIL;
 
-- 
2.30.2


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