* [PATCH 5.10 1/2] ext4: disable fast-commit of encrypted dir operations
2023-01-07 20:37 [PATCH 5.10 0/2] Selected ext4 fast-commit fixes for 5.10-stable Eric Biggers
@ 2023-01-07 20:37 ` Eric Biggers
2023-01-07 20:37 ` [PATCH 5.10 2/2] ext4: don't set up encryption key during jbd2 transaction Eric Biggers
2023-01-12 12:40 ` [PATCH 5.10 0/2] Selected ext4 fast-commit fixes for 5.10-stable Greg KH
2 siblings, 0 replies; 4+ messages in thread
From: Eric Biggers @ 2023-01-07 20:37 UTC (permalink / raw)
To: stable; +Cc: linux-ext4, Theodore Ts'o
From: Eric Biggers <ebiggers@google.com>
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: aa75f4d3daae ("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>
---
fs/ext4/fast_commit.c | 40 ++++++++++++++++++++++---------------
fs/ext4/fast_commit.h | 1 +
include/trace/events/ext4.h | 7 +++++--
3 files changed, 30 insertions(+), 18 deletions(-)
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 41dcf21558c4e..e26020598e194 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -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;
}
@@ -2137,17 +2145,17 @@ 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 d8d0998a5c163..4a5f96a9c9d72 100644
--- a/fs/ext4/fast_commit.h
+++ b/fs/ext4/fast_commit.h
@@ -104,6 +104,7 @@ enum {
EXT4_FC_REASON_FALLOC_RANGE,
EXT4_FC_REASON_INODE_JOURNAL_DATA,
EXT4_FC_COMMIT_FAILED,
+ EXT4_FC_REASON_ENCRYPTED_FILENAME,
EXT4_FC_REASON_MAX
};
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 4973265655a7f..1a91d5789df3b 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),
@@ -2940,7 +2942,7 @@ 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),
@@ -2952,6 +2954,7 @@ 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)
);
--
2.39.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 5.10 2/2] ext4: don't set up encryption key during jbd2 transaction
2023-01-07 20:37 [PATCH 5.10 0/2] Selected ext4 fast-commit fixes for 5.10-stable Eric Biggers
2023-01-07 20:37 ` [PATCH 5.10 1/2] ext4: disable fast-commit of encrypted dir operations Eric Biggers
@ 2023-01-07 20:37 ` Eric Biggers
2023-01-12 12:40 ` [PATCH 5.10 0/2] Selected ext4 fast-commit fixes for 5.10-stable Greg KH
2 siblings, 0 replies; 4+ messages in thread
From: Eric Biggers @ 2023-01-07 20:37 UTC (permalink / raw)
To: stable; +Cc: linux-ext4, syzbot+1a748d0007eeac3ab079, Theodore Ts'o
From: Eric Biggers <ebiggers@google.com>
commit 4c0d5778385cb3618ff26a561ce41de2b7d9de70 upstream.
Commit a80f7fcf1867 ("ext4: fixup ext4_fc_track_* functions' signature")
extended the scope of the transaction in ext4_unlink() too far, making
it include the call to ext4_find_entry(). However, ext4_find_entry()
can deadlock when called from within a transaction because it may need
to set up the directory's encryption key.
Fix this by restoring the transaction to its original scope.
Reported-by: syzbot+1a748d0007eeac3ab079@syzkaller.appspotmail.com
Fixes: a80f7fcf1867 ("ext4: fixup ext4_fc_track_* functions' signature")
Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221106224841.279231-3-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/ext4.h | 4 ++--
fs/ext4/fast_commit.c | 2 +-
fs/ext4/namei.c | 44 +++++++++++++++++++++++--------------------
3 files changed, 27 insertions(+), 23 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index fb9c9e1813bc5..81dc61f1c557f 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3486,8 +3486,8 @@ extern int ext4_handle_dirty_dirblock(handle_t *handle, struct inode *inode,
extern int ext4_ci_compare(const struct inode *parent,
const struct qstr *fname,
const struct qstr *entry, bool quick);
-extern int __ext4_unlink(handle_t *handle, struct inode *dir, const struct qstr *d_name,
- struct inode *inode);
+extern int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
+ struct inode *inode, struct dentry *dentry);
extern int __ext4_link(struct inode *dir, struct inode *inode,
struct dentry *dentry);
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index e26020598e194..be96f5ccc55dd 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1295,7 +1295,7 @@ static int ext4_fc_replay_unlink(struct super_block *sb, struct ext4_fc_tl *tl,
return 0;
}
- ret = __ext4_unlink(NULL, old_parent, &entry, inode);
+ ret = __ext4_unlink(old_parent, &entry, inode, NULL);
/* -ENOENT ok coz it might not exist anymore. */
if (ret == -ENOENT)
ret = 0;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index c17d5f399f9ea..e296b3587bb38 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3244,14 +3244,20 @@ static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
return retval;
}
-int __ext4_unlink(handle_t *handle, struct inode *dir, const struct qstr *d_name,
- struct inode *inode)
+int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
+ struct inode *inode,
+ struct dentry *dentry /* NULL during fast_commit recovery */)
{
int retval = -ENOENT;
struct buffer_head *bh;
struct ext4_dir_entry_2 *de;
+ handle_t *handle;
int skip_remove_dentry = 0;
+ /*
+ * Keep this outside the transaction; it may have to set up the
+ * directory's encryption key, which isn't GFP_NOFS-safe.
+ */
bh = ext4_find_entry(dir, d_name, &de, NULL);
if (IS_ERR(bh))
return PTR_ERR(bh);
@@ -3268,7 +3274,14 @@ int __ext4_unlink(handle_t *handle, struct inode *dir, const struct qstr *d_name
if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
skip_remove_dentry = 1;
else
- goto out;
+ goto out_bh;
+ }
+
+ handle = ext4_journal_start(dir, EXT4_HT_DIR,
+ EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
+ if (IS_ERR(handle)) {
+ retval = PTR_ERR(handle);
+ goto out_bh;
}
if (IS_DIRSYNC(dir))
@@ -3277,12 +3290,12 @@ int __ext4_unlink(handle_t *handle, struct inode *dir, const struct qstr *d_name
if (!skip_remove_dentry) {
retval = ext4_delete_entry(handle, dir, de, bh);
if (retval)
- goto out;
+ goto out_handle;
dir->i_ctime = dir->i_mtime = current_time(dir);
ext4_update_dx_flag(dir);
retval = ext4_mark_inode_dirty(handle, dir);
if (retval)
- goto out;
+ goto out_handle;
} else {
retval = 0;
}
@@ -3295,15 +3308,17 @@ int __ext4_unlink(handle_t *handle, struct inode *dir, const struct qstr *d_name
ext4_orphan_add(handle, inode);
inode->i_ctime = current_time(inode);
retval = ext4_mark_inode_dirty(handle, inode);
-
-out:
+ if (dentry && !retval)
+ ext4_fc_track_unlink(handle, dentry);
+out_handle:
+ ext4_journal_stop(handle);
+out_bh:
brelse(bh);
return retval;
}
static int ext4_unlink(struct inode *dir, struct dentry *dentry)
{
- handle_t *handle;
int retval;
if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
@@ -3321,16 +3336,7 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry)
if (retval)
goto out_trace;
- handle = ext4_journal_start(dir, EXT4_HT_DIR,
- EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
- if (IS_ERR(handle)) {
- retval = PTR_ERR(handle);
- goto out_trace;
- }
-
- retval = __ext4_unlink(handle, dir, &dentry->d_name, d_inode(dentry));
- if (!retval)
- ext4_fc_track_unlink(handle, dentry);
+ retval = __ext4_unlink(dir, &dentry->d_name, d_inode(dentry), dentry);
#ifdef CONFIG_UNICODE
/* VFS negative dentries are incompatible with Encoding and
* Case-insensitiveness. Eventually we'll want avoid
@@ -3341,8 +3347,6 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry)
if (IS_CASEFOLDED(dir))
d_invalidate(dentry);
#endif
- if (handle)
- ext4_journal_stop(handle);
out_trace:
trace_ext4_unlink_exit(dentry, retval);
--
2.39.0
^ permalink raw reply related [flat|nested] 4+ messages in thread