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Date: Sun, 6 Nov 2022 14:48:35 -0800
From: Eric Biggers <ebiggers@...nel.org>
To: linux-ext4@...r.kernel.org
Cc: linux-fscrypt@...r.kernel.org,
Harshad Shirwadkar <harshadshirwadkar@...il.com>,
stable@...r.kernel.org
Subject: [PATCH 1/7] ext4: disable fast-commit of encrypted dir operations
From: Eric Biggers <ebiggers@...gle.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@...r.kernel.org> # v5.10+
Signed-off-by: Eric Biggers <ebiggers@...gle.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)
);
--
2.38.1
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