From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:55120 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932350AbdHVLAh (ORCPT ); Tue, 22 Aug 2017 07:00:37 -0400 Subject: Re: [PATCH 3/3] btrfs: Add sanity check for EXTENT_DATA when reading out leaf From: Nikolay Borisov To: Qu Wenruo , linux-btrfs@vger.kernel.org Cc: dsterba@suse.cz References: <20170822073717.13081-1-quwenruo.btrfs@gmx.com> <20170822073717.13081-4-quwenruo.btrfs@gmx.com> Message-ID: Date: Tue, 22 Aug 2017 14:00:33 +0300 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 22.08.2017 13:57, Nikolay Borisov wrote: > > > On 22.08.2017 10:37, Qu Wenruo wrote: >> Add extra checker for item with EXTENT_DATA type. >> This checks the following thing: >> 1) Item size >> Plain text inline file extent size must match item size. >> (compressed inline file extent has no info about its on-disk size) >> Regular/preallocated file extent size must be a fixed value. >> >> 2) Every member of regular file extent item >> Including alignment for bytenr and offset, possible value for >> compression/encryption/type. >> >> 3) Type/compression/encode must be one of the valid values. >> >> This should be the most comprehensive and restrict check in the context >> of btrfs_item for EXTENT_DATA. >> >> Signed-off-by: Qu Wenruo >> --- >> fs/btrfs/disk-io.c | 88 +++++++++++++++++++++++++++++++++++++++++ >> include/uapi/linux/btrfs_tree.h | 1 + >> 2 files changed, 89 insertions(+) >> >> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c >> index 59ee7b959bf0..557f9a520e2a 100644 >> --- a/fs/btrfs/disk-io.c >> +++ b/fs/btrfs/disk-io.c >> @@ -549,6 +549,83 @@ static int check_tree_block_fsid(struct btrfs_fs_info *fs_info, >> btrfs_header_level(eb) == 0 ? "leaf" : "node", \ >> reason, btrfs_header_bytenr(eb), root->objectid, slot) >> >> +static int check_extent_data_item(struct btrfs_root *root, >> + struct extent_buffer *leaf, int slot) >> +{ >> + struct btrfs_file_extent_item *fi; >> + u32 sectorsize = root->fs_info->sectorsize; >> + u32 item_size = btrfs_item_size_nr(leaf, slot); >> + >> + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); >> + >> + if (btrfs_file_extent_type(leaf, fi) >= BTRFS_FILE_EXTENT_LAST_TYPE) { >> + CORRUPT("invalid file extent type", leaf, root, slot); >> + return -EIO; >> + } >> + if (btrfs_file_extent_compression(leaf, fi) >= BTRFS_COMPRESS_LAST) { >> + CORRUPT("invalid file extent compression", leaf, root, slot); >> + return -EIO; >> + } >> + if (btrfs_file_extent_encryption(leaf, fi)) { >> + CORRUPT("invalid file extent encryption", leaf, root, slot); >> + return -EIO; >> + } >> + if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) { >> + if (btrfs_file_extent_compression(leaf, fi) != >> + BTRFS_COMPRESS_NONE) >> + return 0; >> + /* Plaintext inline extent size must match item size */ >> + if (item_size != BTRFS_FILE_EXTENT_INLINE_DATA_START + >> + btrfs_file_extent_ram_bytes(leaf, fi)) { >> + CORRUPT("plaintext inline extent has invalid size", >> + leaf, root, slot); >> + return -EIO; >> + } >> + return 0; >> + } One more thing - don't we really want to use -EUCLEAN rather than -EIO? >> + >> + >> + /* regular or preallocated extent has fixed item size */ >> + if (item_size != sizeof(*fi)) { >> + CORRUPT( >> + "regluar or preallocated extent data item size is invalid", >> + leaf, root, slot); >> + return -EIO; >> + } >> + if (!IS_ALIGNED(btrfs_file_extent_ram_bytes(leaf, fi), sectorsize) || >> + !IS_ALIGNED(btrfs_file_extent_disk_bytenr(leaf, fi), sectorsize) || >> + !IS_ALIGNED(btrfs_file_extent_disk_num_bytes(leaf, fi), >> + sectorsize) || >> + !IS_ALIGNED(btrfs_file_extent_offset(leaf, fi), sectorsize) || >> + !IS_ALIGNED(btrfs_file_extent_num_bytes(leaf, fi), sectorsize)) { >> + CORRUPT( >> + "regular or preallocated extent data item has unaligned value", >> + leaf, root, slot); >> + return -EIO; >> + } >> + >> + return 0; >> +} >> + >> +static int check_leaf_item(struct btrfs_root *root, >> + struct extent_buffer *leaf, int slot) >> +{ >> + struct btrfs_key key; >> + int ret = 0; >> + >> + btrfs_item_key_to_cpu(leaf, &key, slot); > > nit: We already have the key in the proper format in the caller of this > function. Why not just pass in the type as an argument and save a > redundant call for every item in a leaf? Perhaps it's a > microoptimisation but for very densely populated trees the miniature > cost might build up. > >> + /* >> + * Considering how overcrowded the code will be inside the switch, >> + * complex verification is better to moved its own function. >> + */ >> + switch (key.type) { >> + case BTRFS_EXTENT_DATA_KEY: >> + ret = check_extent_data_item(root, leaf, slot); >> + break; >> + } >> + return ret; >> +} >> + >> static noinline int check_leaf(struct btrfs_root *root, >> struct extent_buffer *leaf) >> { >> @@ -605,9 +682,13 @@ static noinline int check_leaf(struct btrfs_root *root, >> * 1) key order >> * 2) item offset and size >> * No overlap, no hole, all inside the leaf. >> + * 3) item content >> + * If possible, do comprehensive sanity check. >> + * NOTE: All check must only rely on the item data itself. >> */ >> for (slot = 0; slot < nritems; slot++) { >> u32 item_end_expected; >> + int ret; >> >> btrfs_item_key_to_cpu(leaf, &key, slot); >> >> @@ -650,6 +731,13 @@ static noinline int check_leaf(struct btrfs_root *root, >> return -EIO; >> } >> >> + /* >> + * Check if the item size and content meets other limitation >> + */ >> + ret = check_leaf_item(root, leaf, slot); >> + if (ret < 0) >> + return ret; >> + >> prev_key.objectid = key.objectid; >> prev_key.type = key.type; >> prev_key.offset = key.offset; >> diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h >> index 10689e1fdf11..3aadbb74a024 100644 >> --- a/include/uapi/linux/btrfs_tree.h >> +++ b/include/uapi/linux/btrfs_tree.h >> @@ -732,6 +732,7 @@ struct btrfs_balance_item { >> #define BTRFS_FILE_EXTENT_INLINE 0 >> #define BTRFS_FILE_EXTENT_REG 1 >> #define BTRFS_FILE_EXTENT_PREALLOC 2 >> +#define BTRFS_FILE_EXTENT_LAST_TYPE 3 >> >> struct btrfs_file_extent_item { >> /* >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >