109 lines
4.1 KiB
Diff
109 lines
4.1 KiB
Diff
From fe8715e1337a1bad5c49e165ab77c033c334efbc Mon Sep 17 00:00:00 2001
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From: Qu Wenruo <wqu@suse.com>
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Date: Mon, 20 Jul 2020 20:51:08 +0800
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Subject: [PATCH 1/2] btrfs-progs: convert: prevent 32bit overflow for
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cctx->total_bytes
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[BUG]
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When convert is called on a 64GiB ext4 fs, it fails like this:
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$ btrfs-convert /dev/loop0p1
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create btrfs filesystem:
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blocksize: 4096
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nodesize: 16384
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features: extref, skinny-metadata (default)
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checksum: crc32c
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creating ext2 image file
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ERROR: missing data block for bytenr 1048576
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ERROR: failed to create ext2_saved/image: -2
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WARNING: an error occurred during conversion, filesystem is partially created but not finalized and not mountable
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Btrfs-convert also corrupts the source fs:
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$ LANG=C e2fsck /dev/loop0p1 -f
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e2fsck 1.45.6 (20-Mar-2020)
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Resize inode not valid. Recreate<y>? yes
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Pass 1: Checking inodes, blocks, and sizes
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Deleted inode 3681 has zero dtime. Fix<y>? yes
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Inodes that were part of a corrupted orphan linked list found. Fix<y>? yes
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Inode 3744 was part of the orphaned inode list. FIXED.
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Deleted inode 3745 has zero dtime. Fix<y>? yes
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Inode 3747 has INLINE_DATA_FL flag on filesystem without inline data support.
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Clear<y>? yes
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...
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[CAUSE]
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After some debugging, the first strange behavior is, the value of
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cctx->total_bytes is 0 in ext2_open_fs().
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It turns out that, the value assign for cctx->total_bytes could lead to
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bit overflow for the unsigned int value.
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And that 0 cctx->total_bytes leads to various problems for later free
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space calculation.
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For example, in calculate_available_space(), we use cctx->total_bytes to
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ensure we won't create a data chunk beyond device end:
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cue_len = min(cctx->total_bytes - cur_off, cur_len);
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If that cur_offset is also 0, we will create a cache_extent with 0 size,
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which could cause a lot of problems for cache tree search.
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[FIX]
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Do manual casting for the multiply operation, so we could got a real u64
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result. The fix will be applied to all supported fses (ext* and
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reiserfs).
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Reported-by: Christian Zangl <coralllama@gmail.com>
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Reviewed-by: Nikolay Borisov <nborisov@suse.com>
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Signed-off-by: Qu Wenruo <wqu@suse.com>
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Signed-off-by: David Sterba <dsterba@suse.com>
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(cherry picked from commit 670a19828ad40004d05ad70cdd45d58008d3fb51)
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---
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convert/main.c | 1 +
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convert/source-ext2.c | 2 +-
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convert/source-reiserfs.c | 2 +-
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3 files changed, 3 insertions(+), 2 deletions(-)
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diff --git a/convert/main.c b/convert/main.c
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index 7709e9a6..df6a2ae3 100644
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--- a/convert/main.c
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+++ b/convert/main.c
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@@ -1136,6 +1136,7 @@ static int do_convert(const char *devname, u32 convert_flags, u32 nodesize,
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if (ret)
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goto fail;
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+ ASSERT(cctx.total_bytes);
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blocksize = cctx.blocksize;
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total_bytes = (u64)blocksize * (u64)cctx.block_count;
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if (blocksize < 4096) {
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diff --git a/convert/source-ext2.c b/convert/source-ext2.c
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index f11ef651..d73684ef 100644
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--- a/convert/source-ext2.c
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+++ b/convert/source-ext2.c
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@@ -87,7 +87,7 @@ static int ext2_open_fs(struct btrfs_convert_context *cctx, const char *name)
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cctx->fs_data = ext2_fs;
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cctx->blocksize = ext2_fs->blocksize;
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cctx->block_count = ext2_fs->super->s_blocks_count;
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- cctx->total_bytes = ext2_fs->blocksize * ext2_fs->super->s_blocks_count;
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+ cctx->total_bytes = (u64)ext2_fs->super->s_blocks_count * ext2_fs->blocksize;
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cctx->volume_name = strndup((char *)ext2_fs->super->s_volume_name, 16);
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cctx->first_data_block = ext2_fs->super->s_first_data_block;
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cctx->inodes_count = ext2_fs->super->s_inodes_count;
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diff --git a/convert/source-reiserfs.c b/convert/source-reiserfs.c
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index 9fd6b9ab..3b4cb5ad 100644
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--- a/convert/source-reiserfs.c
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+++ b/convert/source-reiserfs.c
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@@ -82,7 +82,7 @@ static int reiserfs_open_fs(struct btrfs_convert_context *cxt, const char *name)
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cxt->fs_data = fs;
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cxt->blocksize = fs->fs_blocksize;
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cxt->block_count = get_sb_block_count(fs->fs_ondisk_sb);
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- cxt->total_bytes = cxt->blocksize * cxt->block_count;
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+ cxt->total_bytes = (u64)cxt->block_count * cxt->blocksize;
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cxt->volume_name = strndup(fs->fs_ondisk_sb->s_label, 16);
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cxt->first_data_block = 0;
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cxt->inodes_count = reiserfs_count_objectids(fs);
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--
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2.26.2
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