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authorAndrey Ryabinin <aryabinin@virtuozzo.com>2018-07-17 12:00:33 -0400
committerMiklos Szeredi <mszeredi@redhat.com>2018-07-26 10:13:11 -0400
commita2477b0e67c52f4364a47c3ad70902bc2a61bd4c (patch)
treecb4724a138dccddd5f972b3174d075bf02cf2914
parent63576c13bd17848376c8ba4a98f5d5151140c4ac (diff)
fuse: Don't access pipe->buffers without pipe_lock()
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>
-rw-r--r--fs/fuse/dev.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ec83b107c1a0..4a9ace7280b9 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1955,12 +1955,15 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1955 if (!fud) 1955 if (!fud)
1956 return -EPERM; 1956 return -EPERM;
1957 1957
1958 pipe_lock(pipe);
1959
1958 bufs = kmalloc_array(pipe->buffers, sizeof(struct pipe_buffer), 1960 bufs = kmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
1959 GFP_KERNEL); 1961 GFP_KERNEL);
1960 if (!bufs) 1962 if (!bufs) {
1963 pipe_unlock(pipe);
1961 return -ENOMEM; 1964 return -ENOMEM;
1965 }
1962 1966
1963 pipe_lock(pipe);
1964 nbuf = 0; 1967 nbuf = 0;
1965 rem = 0; 1968 rem = 0;
1966 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++) 1969 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)