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Revert "ext4: add validity checks for bitmap block numbers", which caused a regression

This commit is contained in:
Ben Hutchings 2018-04-25 21:15:48 +01:00
parent 98017b2bd7
commit 9f2182e09a
3 changed files with 2 additions and 97 deletions
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2
debian/changelog vendored
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@ -18,6 +18,8 @@ linux (4.16.4-1) UNRELEASED; urgency=medium
* [x86,arm64] Disable code signing for upload to unstable
* debian/lib/python/debian_linux/debian.py: Fix binNMU changelog parsing
* debian/lib/python/debian_linux/debian.py: Fix binNMU revision parsing
* Revert "ext4: add validity checks for bitmap block numbers", which
caused a regression
[ Vagrant Cascadian ]
* [arm64] Add patches to support SATA on Tegra210/Jetson-TX1.

96
debian/patches/bugfix/all/ext4-add-validity-checks-for-bitmap-block-numbers.patch vendored
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@ -1,96 +0,0 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Mon, 26 Mar 2018 23:54:10 -0400
Subject: ext4: add validity checks for bitmap block numbers
Origin: https://git.kernel.org/linus/7dac4a1726a9c64a517d595c40e95e2d0d135f6f
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-1093
An privileged attacker can cause a crash by mounting a crafted ext4
image which triggers a out-of-bounds read in the function
ext4_valid_block_bitmap() in fs/ext4/balloc.c.
This issue has been assigned CVE-2018-1093.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=199181
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1560782
Reported-by: Wen Xu <wen.xu@gatech.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
---
fs/ext4/balloc.c | 16 ++++++++++++++--
fs/ext4/ialloc.c | 7 +++++++
2 files changed, 21 insertions(+), 2 deletions(-)
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -340,20 +340,25 @@ static ext4_fsblk_t ext4_valid_block_bit
/* check whether block bitmap block number is set */
blk = ext4_block_bitmap(sb, desc);
offset = blk - group_first_block;
- if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
+ if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize ||
+ !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
/* bad block bitmap */
return blk;
/* check whether the inode bitmap block number is set */
blk = ext4_inode_bitmap(sb, desc);
offset = blk - group_first_block;
- if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
+ if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize ||
+ !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
/* bad block bitmap */
return blk;
/* check whether the inode table block number is set */
blk = ext4_inode_table(sb, desc);
offset = blk - group_first_block;
+ if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize ||
+ EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= sb->s_blocksize)
+ return blk;
next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
EXT4_B2C(sbi, offset + sbi->s_itb_per_group),
EXT4_B2C(sbi, offset));
@@ -419,6 +424,7 @@ struct buffer_head *
ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
{
struct ext4_group_desc *desc;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
struct buffer_head *bh;
ext4_fsblk_t bitmap_blk;
int err;
@@ -427,6 +433,12 @@ ext4_read_block_bitmap_nowait(struct sup
if (!desc)
return ERR_PTR(-EFSCORRUPTED);
bitmap_blk = ext4_block_bitmap(sb, desc);
+ if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
+ (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
+ ext4_error(sb, "Invalid block bitmap block %llu in "
+ "block_group %u", bitmap_blk, block_group);
+ return ERR_PTR(-EFSCORRUPTED);
+ }
bh = sb_getblk(sb, bitmap_blk);
if (unlikely(!bh)) {
ext4_error(sb, "Cannot get buffer for block bitmap - "
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -160,6 +160,7 @@ static struct buffer_head *
ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
{
struct ext4_group_desc *desc;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
struct buffer_head *bh = NULL;
ext4_fsblk_t bitmap_blk;
int err;
@@ -169,6 +170,12 @@ ext4_read_inode_bitmap(struct super_bloc
return ERR_PTR(-EFSCORRUPTED);
bitmap_blk = ext4_inode_bitmap(sb, desc);
+ if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
+ (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
+ ext4_error(sb, "Invalid inode bitmap blk %llu in "
+ "block_group %u", bitmap_blk, block_group);
+ return ERR_PTR(-EFSCORRUPTED);
+ }
bh = sb_getblk(sb, bitmap_blk);
if (unlikely(!bh)) {
ext4_error(sb, "Cannot read inode bitmap - "

1
debian/patches/series vendored
View File

@ -139,7 +139,6 @@ features/all/lockdown/arm64-add-kernel-config-option-to-lock-down-when.patch
# Security fixes
debian/i386-686-pae-pci-set-pci-nobios-by-default.patch
bugfix/all/ext4-add-validity-checks-for-bitmap-block-numbers.patch
# Fix exported symbol versions
bugfix/all/module-disable-matching-missing-version-crc.patch