From 349fa7d6e1935f49bf4161c4900711b2989180a9 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 12 Apr 2018 11:48:09 -0400 Subject: ext4: prevent right-shifting extents beyond EXT_MAX_BLOCKS During the "insert range" fallocate operation, extents starting at the range offset are shifted "right" (to a higher file offset) by the range length. But, as shown by syzbot, it's not validated that this doesn't cause extents to be shifted beyond EXT_MAX_BLOCKS. In that case ->ee_block can wrap around, corrupting the extent tree. Fix it by returning an error if the space between the end of the last extent and EXT4_MAX_BLOCKS is smaller than the range being inserted. This bug can be reproduced by running the following commands when the current directory is on an ext4 filesystem with a 4k block size: fallocate -l 8192 file fallocate --keep-size -o 0xfffffffe000 -l 4096 -n file fallocate --insert-range -l 8192 file Then after unmounting the filesystem, e2fsck reports corruption. Reported-by: syzbot+06c885be0edcdaeab40c@syzkaller.appspotmail.com Fixes: 331573febb6a ("ext4: Add support FALLOC_FL_INSERT_RANGE for fallocate") Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o --- fs/ext4/extents.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'fs/ext4') diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 0a7315961bac..c969275ce3ee 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -5329,8 +5329,9 @@ ext4_ext_shift_extents(struct inode *inode, handle_t *handle, stop = le32_to_cpu(extent->ee_block); /* - * In case of left shift, Don't start shifting extents until we make - * sure the hole is big enough to accommodate the shift. + * For left shifts, make sure the hole on the left is big enough to + * accommodate the shift. For right shifts, make sure the last extent + * won't be shifted beyond EXT_MAX_BLOCKS. */ if (SHIFT == SHIFT_LEFT) { path = ext4_find_extent(inode, start - 1, &path, @@ -5350,9 +5351,14 @@ ext4_ext_shift_extents(struct inode *inode, handle_t *handle, if ((start == ex_start && shift > ex_start) || (shift > start - ex_end)) { - ext4_ext_drop_refs(path); - kfree(path); - return -EINVAL; + ret = -EINVAL; + goto out; + } + } else { + if (shift > EXT_MAX_BLOCKS - + (stop + ext4_ext_get_actual_len(extent))) { + ret = -EINVAL; + goto out; } } -- cgit v1.2.3 From 22be37acce25d66ecf6403fc8f44df9c5ded2372 Mon Sep 17 00:00:00 2001 From: Lukas Czerner Date: Tue, 24 Apr 2018 11:31:44 -0400 Subject: ext4: fix bitmap position validation 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(-) (limited to 'fs/ext4') 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), -- cgit v1.2.3 From 7ef79ad52136712172eb0525bf0b462516bf2f93 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Thu, 26 Apr 2018 00:44:46 -0400 Subject: ext4: add MODULE_SOFTDEP to ensure crc32c is included in the initramfs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fixes: a45403b51582 ("ext4: always initialize the crc32c checksum driver") Reported-by: François Valenduc Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org --- fs/ext4/super.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/ext4') diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 185f7e61f4cf..eb104e8476f0 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5886,5 +5886,6 @@ static void __exit ext4_exit_fs(void) MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others"); MODULE_DESCRIPTION("Fourth Extended Filesystem"); MODULE_LICENSE("GPL"); +MODULE_SOFTDEP("pre: crc32c"); module_init(ext4_init_fs) module_exit(ext4_exit_fs) -- cgit v1.2.3