diff --git a/debian/changelog b/debian/changelog index a65561926..b601c2f92 100644 --- a/debian/changelog +++ b/debian/changelog @@ -18,12 +18,11 @@ 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 * xfs: enhance dinode verifier (CVE-2018-10322) * xfs: set format back to extents if xfs_bmap_extents_to_btree (CVE-2018-10323) * udeb: Add algif_skcipher to crypto-modules (Closes: #896968) + * ext4: fix bitmap position validation (fixes regression in 4.15.17-1) [ Vagrant Cascadian ] * [arm64] Add patches to support SATA on Tegra210/Jetson-TX1. diff --git a/debian/patches/bugfix/all/ext4-add-validity-checks-for-bitmap-block-numbers.patch b/debian/patches/bugfix/all/ext4-add-validity-checks-for-bitmap-block-numbers.patch new file mode 100644 index 000000000..b7f943954 --- /dev/null +++ b/debian/patches/bugfix/all/ext4-add-validity-checks-for-bitmap-block-numbers.patch @@ -0,0 +1,96 @@ +From: Theodore Ts'o +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 +Signed-off-by: Theodore Ts'o +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 +@@ -338,20 +338,25 @@ 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)); +@@ -417,6 +422,7 @@ 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; +@@ -425,6 +431,12 @@ 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 +@@ -122,6 +122,7 @@ 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; +@@ -131,6 +132,12 @@ 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 - " diff --git a/debian/patches/bugfix/all/ext4-fix-bitmap-position-validation.patch b/debian/patches/bugfix/all/ext4-fix-bitmap-position-validation.patch new file mode 100644 index 000000000..14b3dab08 --- /dev/null +++ b/debian/patches/bugfix/all/ext4-fix-bitmap-position-validation.patch @@ -0,0 +1,76 @@ +From: Lukas Czerner +Date: Tue, 24 Apr 2018 11:31:44 -0400 +Subject: ext4: fix bitmap position validation +Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=22be37acce25d66ecf6403fc8f44df9c5ded2372 + +Currently in ext4_valid_block_bitmap() we expect the bitmap to be +positioned anywhere between 0 and s_blocksize clusters, but that's +wrong because the bitmap can be placed anywhere in the block group. This +causes false positives when validating bitmaps on perfectly valid file +system layouts. Fix it by checking whether the bitmap is within the group +boundary. + +The problem can be reproduced using the following + +mkfs -t ext3 -E stride=256 /dev/vdb1 +mount /dev/vdb1 /mnt/test +cd /mnt/test +wget https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.16.3.tar.xz +tar xf linux-4.16.3.tar.xz + +This will result in the warnings in the logs + +EXT4-fs error (device vdb1): ext4_validate_block_bitmap:399: comm tar: bg 84: block 2774529: invalid block bitmap + +[ Changed slightly for clarity and to not drop a overflow test -- TYT ] + +Signed-off-by: Lukas Czerner +Signed-off-by: Theodore Ts'o +Reported-by: Ilya Dryomov +Fixes: 7dac4a1726a9 ("ext4: add validity checks for bitmap block numbers") +Cc: stable@vger.kernel.org +--- + fs/ext4/balloc.c | 9 +++++---- + 1 file changed, 5 insertions(+), 4 deletions(-) + +diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c +index a33d8fb1bf2a..508b905d744d 100644 +--- a/fs/ext4/balloc.c ++++ b/fs/ext4/balloc.c +@@ -321,6 +321,7 @@ static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_grpblk_t offset; + ext4_grpblk_t next_zero_bit; ++ ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); + ext4_fsblk_t blk; + ext4_fsblk_t group_first_block; + +@@ -338,7 +339,7 @@ static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, + /* check whether block bitmap block number is set */ + blk = ext4_block_bitmap(sb, desc); + offset = blk - group_first_block; +- if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize || ++ if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || + !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) + /* bad block bitmap */ + return blk; +@@ -346,7 +347,7 @@ static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, + /* check whether the inode bitmap block number is set */ + blk = ext4_inode_bitmap(sb, desc); + offset = blk - group_first_block; +- if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize || ++ if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || + !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) + /* bad block bitmap */ + return blk; +@@ -354,8 +355,8 @@ static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, + /* 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) ++ if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || ++ EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit) + return blk; + next_zero_bit = ext4_find_next_zero_bit(bh->b_data, + EXT4_B2C(sbi, offset + sbi->s_itb_per_group), diff --git a/debian/patches/series b/debian/patches/series index b4e988379..5b097a58c 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -141,6 +141,8 @@ features/all/lockdown/arm64-add-kernel-config-option-to-lock-down-when.patch debian/i386-686-pae-pci-set-pci-nobios-by-default.patch bugfix/all/xfs-enhance-dinode-verifier.patch bugfix/all/xfs-set-format-back-to-extents-if-xfs_bmap_extents_t.patch +bugfix/all/ext4-add-validity-checks-for-bitmap-block-numbers.patch +bugfix/all/ext4-fix-bitmap-position-validation.patch # Fix exported symbol versions bugfix/all/module-disable-matching-missing-version-crc.patch