4.14-stable review patch. If anyone has any objections, please let me know.
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commit f556faa46eb4e96d0d0772e74ecf66781e132f72 upstream.
Although we have tree level check at tree read runtime, it's completely based on its parent level. We still need to do accurate level check to avoid invalid tree blocks sneak into kernel space.
The check itself is simple, for leaf its level should always be 0. For nodes its level should be in range [1, BTRFS_MAX_LEVEL - 1].
Signed-off-by: Qu Wenruo wqu@suse.com Reviewed-by: Su Yue suy.fnst@cn.fujitsu.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com [bwh: Backported to 4.14: - Pass root instead of fs_info to generic_err() - Adjust context] Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/tree-checker.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index 31756bac75b4..fa8f64119e6f 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -447,6 +447,13 @@ static int check_leaf(struct btrfs_root *root, struct extent_buffer *leaf, u32 nritems = btrfs_header_nritems(leaf); int slot;
+ if (btrfs_header_level(leaf) != 0) { + generic_err(root, leaf, 0, + "invalid level for leaf, have %d expect 0", + btrfs_header_level(leaf)); + return -EUCLEAN; + } + /* * Extent buffers from a relocation tree have a owner field that * corresponds to the subvolume tree they are based on. So just from an @@ -589,9 +596,16 @@ int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node) unsigned long nr = btrfs_header_nritems(node); struct btrfs_key key, next_key; int slot; + int level = btrfs_header_level(node); u64 bytenr; int ret = 0;
+ if (level <= 0 || level >= BTRFS_MAX_LEVEL) { + generic_err(root, node, 0, + "invalid level for node, have %d expect [1, %d]", + level, BTRFS_MAX_LEVEL - 1); + return -EUCLEAN; + } if (nr == 0 || nr > BTRFS_NODEPTRS_PER_BLOCK(root->fs_info)) { btrfs_crit(root->fs_info, "corrupt node: root=%llu block=%llu, nritems too %s, have %lu expect range [1,%u]",