> -----Original Message----- > From: linux-btrfs-ow...@vger.kernel.org > [mailto:linux-btrfs-ow...@vger.kernel.org] On Behalf Of Qu Wenruo > Sent: Tuesday, July 03, 2018 5:10 PM > To: linux-btrfs@vger.kernel.org > Subject: [PATCH 2/5] btrfs: tree-checker: Detect invalid empty essential tree > > A crafted image has empty root tree block, which will cause later NULL > pointer dereference. > > The following trees should never be empty: > 1) Tree root > Must contain at least root items for extent tree, device tree and fs > tree > > 2) Chunk tree > Or we can't even bootstrap. > > 3) Fs tree > At least inode item for top level inode (.). > > 4) Device tree > Dev extents for chunks > > 5) Extent tree > Must has corresponding extent for each chunk. > > If any is empty, we are sure the fs is corrupted and no need to mount > it. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=199847 > Reported-by: Xu Wen <wen...@gatech.edu> > Signed-off-by: Qu Wenruo <w...@suse.com> > --- > fs/btrfs/tree-checker.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c > index 1cd735b099df..3a307efab46b 100644 > --- a/fs/btrfs/tree-checker.c > +++ b/fs/btrfs/tree-checker.c > @@ -497,8 +497,20 @@ static int check_leaf(struct btrfs_fs_info *fs_info, > struct extent_buffer *leaf, > * skip this check for relocation trees. > */ > if (nritems == 0 && !btrfs_header_flag(leaf, BTRFS_HEADER_FLAG_RELOC)) { > + u64 owner = btrfs_header_owner(leaf); > struct btrfs_root *check_root; > > + /* These trees should never be empty */ > + if (owner == BTRFS_ROOT_TREE_OBJECTID || > + owner == BTRFS_CHUNK_TREE_OBJECTID || > + owner == BTRFS_EXTENT_TREE_OBJECTID || > + owner == BTRFS_DEV_TREE_OBJECTID || > + owner == BTRFS_FS_TREE_OBJECTID) { > + generic_err(fs_info, leaf, 0, > + "invalid root, root %llu should never be empty", > + owner); > + return -EUCLEAN; > + } > key.objectid = btrfs_header_owner(leaf); > key.type = BTRFS_ROOT_ITEM_KEY; > key.offset = (u64)-1; > --
Reviewed-by: Gu Jinxiang <g...@cn.fujitsu.com> > 2.18.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > N�Р骒r��y����b�X�肚�v�^�)藓{.n�+�伐�{�n谶�)��骅w* jg�报 �����茛j/�赇z罐���2���ㄨ��&�)摺�a囤�� �G���h��j:+v���w��佶
