| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 118/165] fuse: Dont access pipe->buffers without pipe_lock() | Date | Mon, 3 Sep 2018 18:56:44 +0200 |
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4.14-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 @@ -1941,11 +1941,14 @@ static ssize_t fuse_dev_splice_write(str if (!fud) return -EPERM; + pipe_lock(pipe); + bufs = kmalloc(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++)
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