From: Eric Biggers ebiggers@google.com

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: aa75f4d3daae ("ext4: main fast-commit commit path") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Eric Biggers ebiggers@google.com --- fs/ext4/fast_commit.c | 41 ++++++++++++++++++++++--------------- fs/ext4/fast_commit.h | 1 + include/trace/events/ext4.h | 7 +++++-- 3 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c index 0f6d0a80467d7..6d98f2b39b775 100644 --- a/fs/ext4/fast_commit.c +++ b/fs/ext4/fast_commit.c @@ -420,25 +420,34 @@ 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, + NULL); + 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, NULL); + ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_NOMEM, NULL); 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, NULL); + ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_NOMEM, NULL); mutex_lock(&ei->i_fc_lock); return -ENOMEM; } @@ -2249,17 +2258,17 @@ 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) diff --git a/fs/ext4/fast_commit.h b/fs/ext4/fast_commit.h index a6154c3ed1357..256f2ad27204a 100644 --- a/fs/ext4/fast_commit.h +++ b/fs/ext4/fast_commit.h @@ -96,6 +96,7 @@ enum { EXT4_FC_REASON_RENAME_DIR, EXT4_FC_REASON_FALLOC_RANGE, EXT4_FC_REASON_INODE_JOURNAL_DATA, + EXT4_FC_REASON_ENCRYPTED_FILENAME, EXT4_FC_REASON_MAX };

diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h index 229e8fae66a34..ced95fec3367d 100644 --- a/include/trace/events/ext4.h +++ b/include/trace/events/ext4.h @@ -104,6 +104,7 @@ TRACE_DEFINE_ENUM(EXT4_FC_REASON_RESIZE); TRACE_DEFINE_ENUM(EXT4_FC_REASON_RENAME_DIR); TRACE_DEFINE_ENUM(EXT4_FC_REASON_FALLOC_RANGE); TRACE_DEFINE_ENUM(EXT4_FC_REASON_INODE_JOURNAL_DATA); +TRACE_DEFINE_ENUM(EXT4_FC_REASON_ENCRYPTED_FILENAME); TRACE_DEFINE_ENUM(EXT4_FC_REASON_MAX);

#define show_fc_reason(reason) \ @@ -116,7 +117,8 @@ TRACE_DEFINE_ENUM(EXT4_FC_REASON_MAX); { EXT4_FC_REASON_RESIZE, "RESIZE"}, \ { EXT4_FC_REASON_RENAME_DIR, "RENAME_DIR"}, \ { EXT4_FC_REASON_FALLOC_RANGE, "FALLOC_RANGE"}, \ - { EXT4_FC_REASON_INODE_JOURNAL_DATA, "INODE_JOURNAL_DATA"}) + { EXT4_FC_REASON_INODE_JOURNAL_DATA, "INODE_JOURNAL_DATA"}, \ + { EXT4_FC_REASON_ENCRYPTED_FILENAME, "ENCRYPTED_FILENAME"})

TRACE_EVENT(ext4_other_inode_update_time, TP_PROTO(struct inode *inode, ino_t orig_ino), @@ -2764,7 +2766,7 @@ TRACE_EVENT(ext4_fc_stats, ),

TP_printk("dev %d,%d fc ineligible reasons:\n" - "%s:%u, %s:%u, %s:%u, %s:%u, %s:%u, %s:%u, %s:%u, %s:%u, %s:%u " + "%s:%u, %s:%u, %s:%u, %s:%u, %s:%u, %s:%u, %s:%u, %s:%u, %s:%u, %s:%u" "num_commits:%lu, ineligible: %lu, numblks: %lu", MAJOR(__entry->dev), MINOR(__entry->dev), FC_REASON_NAME_STAT(EXT4_FC_REASON_XATTR), @@ -2776,6 +2778,7 @@ TRACE_EVENT(ext4_fc_stats, FC_REASON_NAME_STAT(EXT4_FC_REASON_RENAME_DIR), FC_REASON_NAME_STAT(EXT4_FC_REASON_FALLOC_RANGE), FC_REASON_NAME_STAT(EXT4_FC_REASON_INODE_JOURNAL_DATA), + FC_REASON_NAME_STAT(EXT4_FC_REASON_ENCRYPTED_FILENAME), __entry->fc_commits, __entry->fc_ineligible_commits, __entry->fc_numblks) );