From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:56753 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758797AbcIWIGk (ORCPT ); Fri, 23 Sep 2016 04:06:40 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: Daeho Jeong , Youngjin Gil , Theodore Ts'o , Jiri Slaby Subject: [patch added to 3.12-stable] ext4: avoid modifying checksum fields directly during checksum verification Date: Fri, 23 Sep 2016 10:06:25 +0200 Message-Id: <20160923080636.9957-2-jslaby@suse.cz> In-Reply-To: <20160923080636.9957-1-jslaby@suse.cz> References: <20160923080636.9957-1-jslaby@suse.cz> Sender: stable-owner@vger.kernel.org List-ID: From: Daeho Jeong This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== commit b47820edd1634dc1208f9212b7ecfb4230610a23 upstream. We temporally change checksum fields in buffers of some types of metadata into '0' for verifying the checksum values. By doing this without locking the buffer, some metadata's checksums, which are being committed or written back to the storage, could be damaged. In our test, several metadata blocks were found with damaged metadata checksum value during recovery process. When we only verify the checksum value, we have to avoid modifying checksum fields directly. Signed-off-by: Daeho Jeong Signed-off-by: Youngjin Gil Signed-off-by: Theodore Ts'o Reviewed-by: Darrick J. Wong Signed-off-by: Jiri Slaby --- fs/ext4/inode.c | 38 ++++++++++++++++++++++---------------- fs/ext4/namei.c | 9 ++++----- fs/ext4/super.c | 18 +++++++++--------- fs/ext4/xattr.c | 13 +++++++------ 4 files changed, 42 insertions(+), 36 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 98ba65482e46..aa9a1e7b0255 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -53,25 +53,31 @@ static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw, struct ext4_inode_info *ei) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); - __u16 csum_lo; - __u16 csum_hi = 0; __u32 csum; + __u16 dummy_csum = 0; + int offset = offsetof(struct ext4_inode, i_checksum_lo); + unsigned int csum_size = sizeof(dummy_csum); - csum_lo = le16_to_cpu(raw->i_checksum_lo); - raw->i_checksum_lo = 0; - if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE && - EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) { - csum_hi = le16_to_cpu(raw->i_checksum_hi); - raw->i_checksum_hi = 0; - } + csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, offset); + csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, csum_size); + offset += csum_size; + csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset, + EXT4_GOOD_OLD_INODE_SIZE - offset); - csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, - EXT4_INODE_SIZE(inode->i_sb)); - - raw->i_checksum_lo = cpu_to_le16(csum_lo); - if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE && - EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) - raw->i_checksum_hi = cpu_to_le16(csum_hi); + if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { + offset = offsetof(struct ext4_inode, i_checksum_hi); + csum = ext4_chksum(sbi, csum, (__u8 *)raw + + EXT4_GOOD_OLD_INODE_SIZE, + offset - EXT4_GOOD_OLD_INODE_SIZE); + if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) { + csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, + csum_size); + offset += csum_size; + csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset, + EXT4_INODE_SIZE(inode->i_sb) - + offset); + } + } return csum; } diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 4587a1b31c93..d2b971da417c 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -414,15 +414,14 @@ static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent, struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); struct ext4_inode_info *ei = EXT4_I(inode); __u32 csum; - __le32 save_csum; int size; + __u32 dummy_csum = 0; + int offset = offsetof(struct dx_tail, dt_checksum); size = count_offset + (count * sizeof(struct dx_entry)); - save_csum = t->dt_checksum; - t->dt_checksum = 0; csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size); - csum = ext4_chksum(sbi, csum, (__u8 *)t, sizeof(struct dx_tail)); - t->dt_checksum = save_csum; + csum = ext4_chksum(sbi, csum, (__u8 *)t, offset); + csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum)); return cpu_to_le32(csum); } diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 2fadd3fa1acc..584d22c58329 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1987,22 +1987,24 @@ failed: static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group, struct ext4_group_desc *gdp) { - int offset; + int offset = offsetof(struct ext4_group_desc, bg_checksum); __u16 crc = 0; __le32 le_group = cpu_to_le32(block_group); if (ext4_has_metadata_csum(sbi->s_sb)) { /* Use new metadata_csum algorithm */ - __le16 save_csum; __u32 csum32; + __u16 dummy_csum = 0; - save_csum = gdp->bg_checksum; - gdp->bg_checksum = 0; csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group, sizeof(le_group)); - csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp, - sbi->s_desc_size); - gdp->bg_checksum = save_csum; + csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp, offset); + csum32 = ext4_chksum(sbi, csum32, (__u8 *)&dummy_csum, + sizeof(dummy_csum)); + offset += sizeof(dummy_csum); + if (offset < sbi->s_desc_size) + csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp + offset, + sbi->s_desc_size - offset); crc = csum32 & 0xFFFF; goto out; @@ -2013,8 +2015,6 @@ static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group, cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM))) return 0; - offset = offsetof(struct ext4_group_desc, bg_checksum); - crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid)); crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group)); crc = crc16(crc, (__u8 *)gdp, offset); diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index a5d2f1b6c5c5..e5835f6e1466 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -123,17 +123,18 @@ static __le32 ext4_xattr_block_csum(struct inode *inode, { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); __u32 csum; - __le32 save_csum; __le64 dsk_block_nr = cpu_to_le64(block_nr); + __u32 dummy_csum = 0; + int offset = offsetof(struct ext4_xattr_header, h_checksum); - save_csum = hdr->h_checksum; - hdr->h_checksum = 0; csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr, sizeof(dsk_block_nr)); - csum = ext4_chksum(sbi, csum, (__u8 *)hdr, - EXT4_BLOCK_SIZE(inode->i_sb)); + csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset); + csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum)); + offset += sizeof(dummy_csum); + csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset, + EXT4_BLOCK_SIZE(inode->i_sb) - offset); - hdr->h_checksum = save_csum; return cpu_to_le32(csum); } -- 2.10.0