vfs: fix uninitialized flags in splice_to_pipe()

commit 5a81e6a171cdbd1fa8bc1fdd80c23d3d71816fac upstream.

Flags (PIPE_BUF_FLAG_PACKET, PIPE_BUF_FLAG_GIFT) could remain on the
unused part of the pipe ring buffer.  Previously splice_to_pipe() left
the flags value alone, which could result in incorrect behavior.

Uninitialized flags appears to have been there from the introduction of
the splice syscall.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/splice.c b/fs/splice.c
index 459128b..4cf2cba 100644 (file)
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -214,6 +214,7 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
                        buf->len = spd->partial[page_nr].len;
                        buf->private = spd->partial[page_nr].private;
                        buf->ops = spd->ops;
+                       buf->flags = 0;
                        if (spd->flags & SPLICE_F_GIFT)
                                buf->flags |= PIPE_BUF_FLAG_GIFT;