On 6/12/19 11:57 AM, Vlastimil Babka wrote:
On 7/17/18 6:00 PM, Andrey Ryabinin wrote:
fuse_dev_splice_write() reads pipe->buffers to determine the size of 'bufs' array before taking the pipe_lock(). This is not safe as another thread might change the 'pipe->buffers' between the allocation and taking the pipe_lock(). So we end up with too small 'bufs' array.
Move the bufs allocations inside pipe_lock()/pipe_unlock() to fix this.
Fixes: dd3bb14f44a6 ("fuse: support splice() writing to fuse device") Signed-off-by: Andrey Ryabinin aryabinin@virtuozzo.com Cc: stable@vger.kernel.org
BTW, why don't we need to do the same in fuse_dev_splice_read()?
do_splice() already takes the pipe_lock() before calling ->splice_read()
Thanks, Vlastimil
fs/fuse/dev.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index c6b88fa85e2e..702592cce546 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1944,12 +1944,15 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, if (!fud) return -EPERM;
- pipe_lock(pipe);
- bufs = kmalloc_array(pipe->buffers, sizeof(struct pipe_buffer), GFP_KERNEL);
- if (!bufs)
- if (!bufs) {
pipe_unlock(pipe);- }
- pipe_lock(pipe); nbuf = 0; rem = 0; for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)