From 15fab63e1e57be9fdb5eec1bbc5916e9825e9acb Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 5 Apr 2019 14:02:10 -0700 Subject: fs: prevent page refcount overflow in pipe_buf_get Change pipe_buf_get() to return a bool indicating whether it succeeded in raising the refcount of the page (if the thing in the pipe is a page). This removes another mechanism for overflowing the page refcount. All callers converted to handle a failure. Reported-by: Jann Horn Signed-off-by: Matthew Wilcox Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- fs/splice.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'fs/splice.c') diff --git a/fs/splice.c b/fs/splice.c index de2ede048473..f30af82b850d 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1588,7 +1588,11 @@ retry: * Get a reference to this pipe buffer, * so we can copy the contents over. */ - pipe_buf_get(ipipe, ibuf); + if (!pipe_buf_get(ipipe, ibuf)) { + if (ret == 0) + ret = -EFAULT; + break; + } *obuf = *ibuf; /* @@ -1660,7 +1664,11 @@ static int link_pipe(struct pipe_inode_info *ipipe, * Get a reference to this pipe buffer, * so we can copy the contents over. */ - pipe_buf_get(ipipe, ibuf); + if (!pipe_buf_get(ipipe, ibuf)) { + if (ret == 0) + ret = -EFAULT; + break; + } obuf = opipe->bufs + nbuf; *obuf = *ibuf; -- cgit v1.2.3-59-g8ed1b