| From c4e9a5b16c8e044f25652be2ef8d900b8958126d Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 14 Aug 2023 11:29:01 -0700 |
| Subject: ext4: reject casefold inode flag without casefold feature |
| |
| From: Eric Biggers <ebiggers@google.com> |
| |
| [ Upstream commit 8216776ccff6fcd40e3fdaa109aa4150ebe760b3 ] |
| |
| It is invalid for the casefold inode flag to be set without the casefold |
| superblock feature flag also being set. e2fsck already considers this |
| case to be invalid and handles it by offering to clear the casefold flag |
| on the inode. __ext4_iget() also already considered this to be invalid, |
| sort of, but it only got so far as logging an error message; it didn't |
| actually reject the inode. Make it reject the inode so that other code |
| doesn't have to handle this case. This matches what f2fs does. |
| |
| Note: we could check 's_encoding != NULL' instead of |
| ext4_has_feature_casefold(). This would make the check robust against |
| the casefold feature being enabled by userspace writing to the page |
| cache of the mounted block device. However, it's unsolvable in general |
| for filesystems to be robust against concurrent writes to the page cache |
| of the mounted block device. Though this very particular scenario |
| involving the casefold feature is solvable, we should not pretend that |
| we can support this model, so let's just check the casefold feature. |
| tune2fs already forbids enabling casefold on a mounted filesystem. |
| |
| Signed-off-by: Eric Biggers <ebiggers@google.com> |
| Link: https://lore.kernel.org/r/20230814182903.37267-2-ebiggers@kernel.org |
| Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
| Stable-dep-of: 642335f3ea2b ("ext4: don't treat fhandle lookup of ea_inode as FS corruption") |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| fs/ext4/inode.c | 5 ++++- |
| 1 file changed, 4 insertions(+), 1 deletion(-) |
| |
| diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c |
| index c991955412a49..d0fcf91ec9d62 100644 |
| --- a/fs/ext4/inode.c |
| +++ b/fs/ext4/inode.c |
| @@ -5004,9 +5004,12 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, |
| "iget: bogus i_mode (%o)", inode->i_mode); |
| goto bad_inode; |
| } |
| - if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb)) |
| + if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb)) { |
| ext4_error_inode(inode, function, line, 0, |
| "casefold flag without casefold feature"); |
| + ret = -EFSCORRUPTED; |
| + goto bad_inode; |
| + } |
| if ((err_str = check_igot_inode(inode, flags)) != NULL) { |
| ext4_error_inode(inode, function, line, 0, err_str); |
| ret = -EFSCORRUPTED; |
| -- |
| 2.39.5 |
| |
