3.16.63-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Theodore Ts'o <[email protected]> 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 <[email protected]> Reported-by: [email protected] [bwh: Backported to 3.16: - Drop IS_ENCRYPTED() check - Adjust context] Signed-off-by: Ben Hutchings <[email protected]> --- fs/ext4/ioctl.c | 33 +++++++++++++++++++++++++++------ 1 file changed, 27 insertions(+), 6 deletions(-) --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -64,7 +64,6 @@ static void swap_inode_data(struct inode 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 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(struc 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(struc * 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(struc 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(struc 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(struc /* 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);
