4.18-stable review patch. If anyone has any objections, please let me know.
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From: Andrey Ryabinin aryabinin@virtuozzo.com
commit a2477b0e67c52f4364a47c3ad70902bc2a61bd4c upstream.
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 # v2.6.35 Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/fuse/dev.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1944,12 +1944,15 @@ static ssize_t fuse_dev_splice_write(str 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); return -ENOMEM; + }
- pipe_lock(pipe); nbuf = 0; rem = 0; for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)