diff options
| author | Michal Luczaj <mhal@rbox.co> | 2025-07-25 13:33:04 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-15 17:39:23 +0300 |
| commit | 932a6714d6bb05c35cbc0656559d72693696bd95 (patch) | |
| tree | 7f55b8eb40dc8e13c2bfaa1e1f9c2146c9e36f34 | |
| parent | 424ad833e27e7f9706798b02a324d60e080a9908 (diff) | |
| download | linux-932a6714d6bb05c35cbc0656559d72693696bd95.tar.xz | |
kcm: Fix splice support
[ Upstream commit 9063de636cee235bd736ab3e4895e2826e606dea ]
Flags passed in for splice() syscall should not end up in
skb_recv_datagram(). As SPLICE_F_NONBLOCK == MSG_PEEK, kernel gets
confused: skb isn't unlinked from a receive queue, while strp_msg::offset
and strp_msg::full_len are updated.
Unbreak the logic a bit more by mapping both O_NONBLOCK and
SPLICE_F_NONBLOCK to MSG_DONTWAIT. This way we align with man splice(2) in
regard to errno EAGAIN:
SPLICE_F_NONBLOCK was specified in flags or one of the file descriptors
had been marked as nonblocking (O_NONBLOCK), and the operation would
block.
Fixes: 5121197ecc5d ("kcm: close race conditions on sk_receive_queue")
Fixes: 91687355b927 ("kcm: Splice support")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Link: https://patch.msgid.link/20250725-kcm-splice-v1-1-9a725ad2ee71@rbox.co
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/kcm/kcmsock.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c index 24aec295a51c..c05047dad62d 100644 --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -19,6 +19,7 @@ #include <linux/rculist.h> #include <linux/skbuff.h> #include <linux/socket.h> +#include <linux/splice.h> #include <linux/uaccess.h> #include <linux/workqueue.h> #include <linux/syscalls.h> @@ -1030,6 +1031,11 @@ static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos, ssize_t copied; struct sk_buff *skb; + if (sock->file->f_flags & O_NONBLOCK || flags & SPLICE_F_NONBLOCK) + flags = MSG_DONTWAIT; + else + flags = 0; + /* Only support splice for SOCKSEQPACKET */ skb = skb_recv_datagram(sk, flags, &err); |