diff options
| author | Matthew Wilcox <willy@infradead.org> | 2020-02-26 01:46:14 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-03-11 07:51:15 +0100 |
| commit | c326585619b99cce3240403faa56f599e06893cb (patch) | |
| tree | 6663a07016b0db5d424fe8c51df09726c95c8e37 /fs/fuse/dev.c | |
| parent | 842fc0ee42c4949eda996ed7fbe122e75110e919 (diff) | |
fs: prevent page refcount overflow in pipe_buf_get
commit 15fab63e1e57be9fdb5eec1bbc5916e9825e9acb upstream.
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 <jannh@google.com>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ 4.4.y backport notes:
Regarding the change in generic_pipe_buf_get(), note that
page_cache_get() is the same as get_page(). See mainline commit
09cbfeaf1a5a6 "mm, fs: get rid of PAGE_CACHE_* and
page_cache_{get,release} macros" for context. ]
Signed-off-by: Ajay Kaher <akaher@vmware.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/fuse/dev.c')
| -rw-r--r-- | fs/fuse/dev.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 36a5df92eb9c..16891f5364af 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -2031,10 +2031,8 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; ret = -EINVAL; - if (rem < len) { - pipe_unlock(pipe); - goto out; - } + if (rem < len) + goto out_free; rem = len; while (rem) { @@ -2052,7 +2050,9 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); pipe->nrbufs--; } else { - pipe_buf_get(pipe, ibuf); + if (!pipe_buf_get(pipe, ibuf)) + goto out_free; + *obuf = *ibuf; obuf->flags &= ~PIPE_BUF_FLAG_GIFT; obuf->len = rem; @@ -2075,13 +2075,13 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, ret = fuse_dev_do_write(fud, &cs, len); pipe_lock(pipe); +out_free: for (idx = 0; idx < nbuf; idx++) { struct pipe_buffer *buf = &bufs[idx]; buf->ops->release(pipe, buf); } pipe_unlock(pipe); -out: kfree(bufs); return ret; } |