diff options
| author | Michal Luczaj <mhal@rbox.co> | 2025-07-25 12:33:04 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-30 18:01:26 -0700 |
| commit | 9063de636cee235bd736ab3e4895e2826e606dea (patch) | |
| tree | 0840834e29d795cc587d6f60f7c4c62dc65502a5 /net/kcm/kcmsock.c | |
| parent | d9104cec3e8fe4b458b74709853231385779001f (diff) | |
kcm: Fix splice support
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>
Diffstat (limited to 'net/kcm/kcmsock.c')
| -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 a0be3896a934..a4971e6fa943 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> @@ -1029,6 +1030,11 @@ 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); |