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ext4: disable fast-commit of encrypted dir operations

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commit 0fbcb5251fc81b58969b272c4fb7374a7b922e3e upstream.

fast-commit of create, link, and unlink operations in encrypted
directories is completely broken because the unencrypted filenames are
being written to the fast-commit journal instead of the encrypted
filenames.  These operations can't be replayed, as encryption keys
aren't present at journal replay time.  It is also an information leak.

Until if/when we can get this working properly, make encrypted directory
operations ineligible for fast-commit.

Note that fast-commit operations on encrypted regular files continue to
be allowed, as they seem to work.

Fixes: aa75f4d3da ("ext4: main fast-commit commit path")
Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221106224841.279231-2-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eric Biggers
2022-11-06 14:48:35 -08:00
committed by Greg Kroah-Hartman
parent 5b700b9c04
commit d9ff5ad203
3 changed files with 30 additions and 18 deletions
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40
fs/ext4/fast_commit.c
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@@ -371,25 +371,33 @@ static int __track_dentry_update(struct inode *inode, void *arg, bool update)
struct __track_dentry_update_args *dentry_update =
(struct __track_dentry_update_args *)arg;
struct dentry *dentry = dentry_update->dentry;
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct inode *dir = dentry->d_parent->d_inode;
struct super_block *sb = inode->i_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
mutex_unlock(&ei->i_fc_lock);
if (IS_ENCRYPTED(dir)) {
ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_ENCRYPTED_FILENAME);
mutex_lock(&ei->i_fc_lock);
return -EOPNOTSUPP;
}
node = kmem_cache_alloc(ext4_fc_dentry_cachep, GFP_NOFS);
if (!node) {
ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM);
ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_NOMEM);
mutex_lock(&ei->i_fc_lock);
return -ENOMEM;
}
node->fcd_op = dentry_update->op;
node->fcd_parent = dentry->d_parent->d_inode->i_ino;
node->fcd_parent = dir->i_ino;
node->fcd_ino = inode->i_ino;
if (dentry->d_name.len > DNAME_INLINE_LEN) {
node->fcd_name.name = kmalloc(dentry->d_name.len, GFP_NOFS);
if (!node->fcd_name.name) {
kmem_cache_free(ext4_fc_dentry_cachep, node);
ext4_fc_mark_ineligible(inode->i_sb,
EXT4_FC_REASON_NOMEM);
ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_NOMEM);
mutex_lock(&ei->i_fc_lock);
return -ENOMEM;
}
@@ -2142,17 +2150,17 @@ void ext4_fc_init(struct super_block *sb, journal_t *journal)
journal->j_fc_cleanup_callback = ext4_fc_cleanup;
}
static const char *fc_ineligible_reasons[] = {
"Extended attributes changed",
"Cross rename",
"Journal flag changed",
"Insufficient memory",
"Swap boot",
"Resize",
"Dir renamed",
"Falloc range op",
"Data journalling",
"FC Commit Failed"
static const char * const fc_ineligible_reasons[] = {
[EXT4_FC_REASON_XATTR] = "Extended attributes changed",
[EXT4_FC_REASON_CROSS_RENAME] = "Cross rename",
[EXT4_FC_REASON_JOURNAL_FLAG_CHANGE] = "Journal flag changed",
[EXT4_FC_REASON_NOMEM] = "Insufficient memory",
[EXT4_FC_REASON_SWAP_BOOT] = "Swap boot",
[EXT4_FC_REASON_RESIZE] = "Resize",
[EXT4_FC_REASON_RENAME_DIR] = "Dir renamed",
[EXT4_FC_REASON_FALLOC_RANGE] = "Falloc range op",
[EXT4_FC_REASON_INODE_JOURNAL_DATA] = "Data journalling",
[EXT4_FC_REASON_ENCRYPTED_FILENAME] = "Encrypted filename",
};
int ext4_fc_info_show(struct seq_file *seq, void *v)