[PATCH 4.19 118/190] ext4: protect journal inodes blocks using block_validity

Greg Kroah-Hartman
2019-09-13T13:30:06Z

[ Upstream commit 345c0dbf3a30872d9b204db96b5857cd00808cae ]

Add the blocks which belong to the journal inode to block_validity's
system zone so attempts to deallocate or overwrite the journal due a
corrupted file system where the journal blocks are also claimed by
another inode.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202879
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ext4/block_validity.c | 48 ++++++++++++++++++++++++++++++++++++++++
fs/ext4/inode.c | 4 ++++
2 files changed, 52 insertions(+)

diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index 913061c0de1b3..9409b1e11a22e 100644
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -137,6 +137,48 @@ static void debug_print_tree(struct ext4_sb_info *sbi)
printk(KERN_CONT "\n");
}

+static int ext4_protect_reserved_inode(struct super_block *sb, u32 ino)
+{
+ struct inode *inode;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_map_blocks map;
+ u32 i = 0, err = 0, num, n;
+
+ if ((ino < EXT4_ROOT_INO) ||
+ (ino > le32_to_cpu(sbi->s_es->s_inodes_count)))
+ return -EINVAL;
+ inode = ext4_iget(sb, ino, EXT4_IGET_SPECIAL);
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+ num = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+ while (i < num) {
+ map.m_lblk = i;
+ map.m_len = num - i;
+ n = ext4_map_blocks(NULL, inode, &map, 0);
+ if (n < 0) {
+ err = n;
+ break;
+ }
+ if (n == 0) {
+ i++;
+ } else {
+ if (!ext4_data_block_valid(sbi, map.m_pblk, n)) {
+ ext4_error(sb, "blocks %llu-%llu from inode %u "
+ "overlap system zone", map.m_pblk,
+ map.m_pblk + map.m_len - 1, ino);
+ err = -EFSCORRUPTED;
+ break;
+ }
+ err = add_system_zone(sbi, map.m_pblk, n);
+ if (err < 0)
+ break;
+ i += n;
+ }
+ }
+ iput(inode);
+ return err;
+}
+
int ext4_setup_system_zone(struct super_block *sb)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
@@ -171,6 +213,12 @@ int ext4_setup_system_zone(struct super_block *sb)
if (ret)
return ret;
}
+ if (ext4_has_feature_journal(sb) && sbi->s_es->s_journal_inum) {
+ ret = ext4_protect_reserved_inode(sb,
+ le32_to_cpu(sbi->s_es->s_journal_inum));
+ if (ret)
+ return ret;
+ }

if (test_opt(sb, DEBUG))
debug_print_tree(sbi);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e65559bf77281..cff6277f7a9ff 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -399,6 +399,10 @@ static int __check_block_validity(struct inode *inode, const char *func,
unsigned int line,
struct ext4_map_blocks *map)
{
+ if (ext4_has_feature_journal(inode->i_sb) &&
+ (inode->i_ino ==
+ le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
+ return 0;
if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
map->m_len)) {
ext4_error_inode(inode, func, line, map->m_pblk,
--
2.20.1