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author | Theodore Ts'o <tytso@mit.edu> | 2018-10-02 18:21:19 -0400 |
---|---|---|
committer | Ben Hutchings <ben@decadent.org.uk> | 2019-02-11 17:53:25 +0000 |
commit | c82376e6b9a215539771aec03a95f0aa8f2e48a6 (patch) | |
tree | bfa55a3daca8e1e397f6a39f7505b31093f5ecc5 /fs | |
parent | 7a6fe647fd5468d4b94f29b30fc009cb2d80ba3c (diff) | |
download | linux-stable-c82376e6b9a215539771aec03a95f0aa8f2e48a6.tar.gz linux-stable-c82376e6b9a215539771aec03a95f0aa8f2e48a6.tar.bz2 linux-stable-c82376e6b9a215539771aec03a95f0aa8f2e48a6.zip |
ext4: fix EXT4_IOC_SWAP_BOOT
commit 18aded17492088962ef43f00825179598b3e8c58 upstream.
The code EXT4_IOC_SWAP_BOOT ioctl hasn't been updated in a while, and
it's a bit broken with respect to more modern ext4 kernels, especially
metadata checksums.
Other problems fixed with this commit:
* Don't allow installing a DAX, swap file, or an encrypted file as a
boot loader.
* Respect the immutable and append-only flags.
* Wait until any DIO operations are finished *before* calling
truncate_inode_pages().
* Don't swap inode->i_flags, since these flags have nothing to do with
the inode blocks --- and it will give the IMA/audit code heartburn
when the inode is evicted.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: syzbot+e81ccd4744c6c4f71354@syzkaller.appspotmail.com
[bwh: Backported to 3.16:
- Drop IS_ENCRYPTED() check
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/ext4/ioctl.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index bfda18a15592..723a2307a9e8 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -64,7 +64,6 @@ static void swap_inode_data(struct inode *inode1, struct inode *inode2) ei1 = EXT4_I(inode1); ei2 = EXT4_I(inode2); - memswap(&inode1->i_flags, &inode2->i_flags, sizeof(inode1->i_flags)); memswap(&inode1->i_version, &inode2->i_version, sizeof(inode1->i_version)); memswap(&inode1->i_blocks, &inode2->i_blocks, @@ -86,6 +85,21 @@ static void swap_inode_data(struct inode *inode1, struct inode *inode2) i_size_write(inode2, isize); } +static void reset_inode_seed(struct inode *inode) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + __le32 inum = cpu_to_le32(inode->i_ino); + __le32 gen = cpu_to_le32(inode->i_generation); + __u32 csum; + + if (!ext4_has_metadata_csum(inode->i_sb)) + return; + + csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum, sizeof(inum)); + ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen, sizeof(gen)); +} + /** * Swap the information from the given @inode and the inode * EXT4_BOOT_LOADER_INO. It will basically swap i_data and all other @@ -104,10 +118,13 @@ static long swap_inode_boot_loader(struct super_block *sb, struct ext4_inode_info *ei_bl; struct ext4_sb_info *sbi = EXT4_SB(sb); - if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode)) + if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode) || + IS_SWAPFILE(inode) || + ext4_has_inline_data(inode)) return -EINVAL; - if (!inode_owner_or_capable(inode) || !capable(CAP_SYS_ADMIN)) + if (IS_RDONLY(inode) || IS_APPEND(inode) || IS_IMMUTABLE(inode) || + !inode_owner_or_capable(inode) || !capable(CAP_SYS_ADMIN)) return -EPERM; inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO); @@ -122,15 +139,15 @@ static long swap_inode_boot_loader(struct super_block *sb, * that only 1 swap_inode_boot_loader is running. */ lock_two_nondirectories(inode, inode_bl); - truncate_inode_pages(&inode->i_data, 0); - truncate_inode_pages(&inode_bl->i_data, 0); - /* Wait for all existing dio workers */ ext4_inode_block_unlocked_dio(inode); ext4_inode_block_unlocked_dio(inode_bl); inode_dio_wait(inode); inode_dio_wait(inode_bl); + truncate_inode_pages(&inode->i_data, 0); + truncate_inode_pages(&inode_bl->i_data, 0); + handle = ext4_journal_start(inode_bl, EXT4_HT_MOVE_EXTENTS, 2); if (IS_ERR(handle)) { err = -EINVAL; @@ -166,6 +183,8 @@ static long swap_inode_boot_loader(struct super_block *sb, inode->i_generation = sbi->s_next_generation++; inode_bl->i_generation = sbi->s_next_generation++; spin_unlock(&sbi->s_next_gen_lock); + reset_inode_seed(inode); + reset_inode_seed(inode_bl); ext4_discard_preallocations(inode); @@ -176,6 +195,7 @@ static long swap_inode_boot_loader(struct super_block *sb, inode->i_ino, err); /* Revert all changes: */ swap_inode_data(inode, inode_bl); + ext4_mark_inode_dirty(handle, inode); } else { err = ext4_mark_inode_dirty(handle, inode_bl); if (err < 0) { @@ -185,6 +205,7 @@ static long swap_inode_boot_loader(struct super_block *sb, /* Revert all changes: */ swap_inode_data(inode, inode_bl); ext4_mark_inode_dirty(handle, inode); + ext4_mark_inode_dirty(handle, inode_bl); } } ext4_journal_stop(handle); |