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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-06-29 16:06:58 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-21 16:15:47 +0300 |
| commit | 36ba38996001ffc0690c79f74a6daad0ea4dae7e (patch) | |
| tree | c3d259db8600d72ea824507316d57c37e3e1259c /fs/splice.c | |
| parent | 7430e587643af437058ce0b92545dedf0a07957b (diff) | |
| download | linux-36ba38996001ffc0690c79f74a6daad0ea4dae7e.tar.xz | |
fs: check FMODE_LSEEK to control internal pipe splicing
[ Upstream commit 97ef77c52b789ec1411d360ed99dca1efe4b2c81 ]
The original direct splicing mechanism from Jens required the input to
be a regular file because it was avoiding the special socket case. It
also recognized blkdevs as being close enough to a regular file. But it
forgot about chardevs, which behave the same way and work fine here.
This is an okayish heuristic, but it doesn't totally work. For example,
a few chardevs should be spliceable here. And a few regular files
shouldn't. This patch fixes this by instead checking whether FMODE_LSEEK
is set, which represents decently enough what we need rewinding for when
splicing to internal pipes.
Fixes: b92ce5589374 ("[PATCH] splice: add direct fd <-> fd splicing support")
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/splice.c')
| -rw-r--r-- | fs/splice.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/fs/splice.c b/fs/splice.c index 866d5c2367b2..6610e55c0e2a 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -806,17 +806,15 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, { struct pipe_inode_info *pipe; long ret, bytes; - umode_t i_mode; size_t len; int i, flags, more; /* - * We require the input being a regular file, as we don't want to - * randomly drop data for eg socket -> socket splicing. Use the - * piped splicing for that! + * We require the input to be seekable, as we don't want to randomly + * drop data for eg socket -> socket splicing. Use the piped splicing + * for that! */ - i_mode = file_inode(in)->i_mode; - if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) + if (unlikely(!(in->f_mode & FMODE_LSEEK))) return -EINVAL; /* |