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* ext4: always check block group bounds in ext4_init_block_bitmap()Theodore Ts'o2018-12-021-7/+3
| | | | | | | | | | | | | | | | commit 819b23f1c501b17b9694325471789e6b5cc2d0d2 upstream. Regardless of whether the flex_bg feature is set, we should always check to make sure the bits we are setting in the block bitmap are within the block group bounds. https://bugzilla.kernel.org/show_bug.cgi?id=199865 Signed-off-by: Theodore Ts'o <tytso@mit.edu> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ext4: only look at the bg_flags field if it is validTheodore Ts'o2018-12-021-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 8844618d8aa7a9973e7b527d038a2a589665002c upstream. The bg_flags field in the block group descripts is only valid if the uninit_bg or metadata_csum feature is enabled. We were not consistently looking at this field; fix this. Also block group #0 must never have uninitialized allocation bitmaps, or need to be zeroed, since that's where the root inode, and other special inodes are set up. Check for these conditions and mark the file system as corrupted if they are detected. This addresses CVE-2018-10876. https://bugzilla.kernel.org/show_bug.cgi?id=199403 Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org [bwh: Backported to 3.16: - ext4_read_block_bitmap_nowait() and ext4_read_inode_bitmap() return a pointer (NULL on error) instead of an error code - Open-code sb_rdonly() - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> [ghackmann@google.com: forward-port to 3.18: adjust context] Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ext4: fix bitmap position validationLukas Czerner2018-12-021-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 22be37acce25d66ecf6403fc8f44df9c5ded2372 upstream. 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 <lczerner@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reported-by: Ilya Dryomov <idryomov@gmail.com> Fixes: 7dac4a1726a9 ("ext4: add validity checks for bitmap block numbers") Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ext4: add validity checks for bitmap block numbersTheodore Ts'o2018-12-021-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | commit 7dac4a1726a9c64a517d595c40e95e2d0d135f6f upstream. 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. Backport notes: 3.18.y is missing commit 6a797d273783 ("ext4: call out CRC and corruption errors with specific error codes") so the EFSCORRUPTED label doesn't exist. Replaced all instances of EFSCORRUPTED with EUCLEAN since that's what 6a797d273783 defined it as. 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 [harsh@prjkt.io: s/EFSCORRUPTED/EUCLEAN/ fs/ext4/balloc.c] Signed-off-by: Harsh Shandilya <harsh@prjkt.io> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ext4: don't update checksum of new initialized bitmapsTheodore Ts'o2018-12-011-2/+1
| | | | | | | | | | | | | | | | | | | commit 044e6e3d74a3d7103a0c8a9305dfd94d64000660 upstream. When reading the inode or block allocation bitmap, if the bitmap needs to be initialized, do not update the checksum in the block group descriptor. That's because we're not set up to journal those changes. Instead, just set the verified bit on the bitmap block, so that it's not necessary to validate the checksum. When a block or inode allocation actually happens, at that point the checksum will be calculated, and update of the bg descriptor block will be properly journalled. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org Signed-off-by: Harsh Shandilya <harsh@prjkt.io> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ext4: validate s_reserved_gdt_blocks on mountTheodore Ts'o2017-12-311-0/+3
| | | | | | | | | | | | | | | | | If s_reserved_gdt_blocks is extremely large, it's possible for ext4_init_block_bitmap(), which is called when ext4 sets up an uninitialized block bitmap, to corrupt random kernel memory. Add the same checks which e2fsck has --- it must never be larger than blocksize / sizeof(__u32) --- and then add a backup check in ext4_init_block_bitmap() in case the superblock gets modified after the file system is mounted. Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org [@nathanchance: fixed conflicts] Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Joe Maples <joe@frap129.org>
* BACKPORT: ext4 from 3.18 to mtk-3.10Mister Oyster2017-05-271-52/+97
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* first commitMeizu OpenSource2016-08-151-0/+838