This is a note to let you know that I've just added the patch titled can: isotp: restore accidentally removed MSG_PEEK feature to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: can-isotp-restore-accidentally-removed-msg_peek-feat.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2750dae9a56fb3450fd29fdaa0e6c09c199595be Author: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Date: Mon Mar 28 13:36:11 2022 +0200 can: isotp: restore accidentally removed MSG_PEEK feature [ Upstream commit e382fea8ae54f5bb62869c6b69b33993d43adeca ] 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 Link: https://lore.kernel.org/all/20220328113611.3691-1-socketcan@xxxxxxxxxxxx Reported-by: Derek Will <derekrobertwill@xxxxxxxxx> Suggested-by: Derek Will <derekrobertwill@xxxxxxxxx> Tested-by: Derek Will <derekrobertwill@xxxxxxxxx> Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/can/isotp.c b/net/can/isotp.c index 671c3673b7ea..63e6e8923200 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1007,7 +1007,7 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, 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)