2009-04-24 20:46:06

by Theodore Ts'o

Subject: [PATCH] ext4: Fix softlockup caused by illegal i_file_acl value in on-disk inode

If the block containing external extended attributes (which is stored
in i_file_acl and i_file_acl_high) is larger than the on-disk
filesystem, the process which tried to access the extended attributes
will endlessly issue kernel printks complaining that
"__find_get_block_slow() failed", locking up that CPU until the system
is forcibly rebooted.

So when we read in the inode, make sure the i_file_acl value is legal,
and if not, flag the filesystem as being corrupted.

Signed-off-by: "Theodore Ts'o" <[email protected]>
---
fs/ext4/inode.c | 12 +++++++++++-
1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c6bd6ce..cab75bb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4409,7 +4409,17 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
(__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
}

- if (ei->i_flags & EXT4_EXTENTS_FL) {
+ if (ei->i_file_acl &&
+ ((ei->i_file_acl <
+ (le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) +
+ EXT4_SB(sb)->s_gdb_count)) ||
+ (ei->i_file_acl >= ext4_blocks_count(EXT4_SB(sb)->s_es)))) {
+ ext4_error(sb, __func__,
+ "bad extended attribute block %llu in inode #%lu",
+ ei->i_file_acl, inode->i_ino);
+ ret = -EIO;
+ goto bad_inode;
+ } else if (ei->i_flags & EXT4_EXTENTS_FL) {
/* Validate extent which is part of inode */
ret = ext4_ext_check_inode(inode);
} else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
--
1.5.6.3

2009-04-24 20:46:06

by Theodore Ts'o

Subject: [PATCH] ext4: Ignore i_file_acl_high unless EXT4_FEATURE_INCOMPAT_64BIT is present

Don't try to look at i_file_acl_high unless the INCOMPAT_64BIT feature
bit is set. The field is normally zero, but older versions of e2fsck
didn't automatically check to make sure of this, so in the spirit of
"be liberal in what you accept", don't look at i_file_acl_high unless
we are using a 64-bit filesystem.

Signed-off-by: "Theodore Ts'o" <[email protected]>
---
fs/ext4/inode.c | 4 +---
1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index cab75bb..1146003 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4357,11 +4357,9 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
ei->i_flags = le32_to_cpu(raw_inode->i_flags);
inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
- if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
- cpu_to_le32(EXT4_OS_HURD)) {
+ if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
ei->i_file_acl |=
((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
- }
inode->i_size = ext4_isize(raw_inode);
ei->i_disksize = inode->i_size;
inode->i_generation = le32_to_cpu(raw_inode->i_generation);
--
1.5.6.3