btrfs: lzo: Harden inline lzo compressed extent decompression

For inlined extent, we only have one segment, thus less things to check.
And further more, inlined extent always has the csum in its leaf header,
it's less probable to have corrupted data.

Anyway, still check header and segment header.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index 464fbb96af1a01a7abc2f26b75eeff8ed00e83dc..b6a4cc178beefd3cee6ce5573f0954fa084b71f0 100644 (file)
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -430,15 +430,24 @@ static int lzo_decompress(struct list_head *ws, unsigned char *data_in,
        struct workspace *workspace = list_entry(ws, struct workspace, list);
        size_t in_len;
        size_t out_len;
+       size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
        int ret = 0;
        char *kaddr;
        unsigned long bytes;
 
-       BUG_ON(srclen < LZO_LEN);
+       if (srclen < LZO_LEN || srclen > max_segment_len + LZO_LEN * 2)
+               return -EUCLEAN;
 
+       in_len = read_compress_length(data_in);
+       if (in_len != srclen)
+               return -EUCLEAN;
        data_in += LZO_LEN;
 
        in_len = read_compress_length(data_in);
+       if (in_len != srclen - LZO_LEN * 2) {
+               ret = -EUCLEAN;
+               goto out;
+       }
        data_in += LZO_LEN;
 
        out_len = PAGE_SIZE;