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Message-Id: <20210325181220.1118705-1-leah.rumancik@gmail.com>
Date: Thu, 25 Mar 2021 18:12:19 +0000
From: Leah Rumancik <leah.rumancik@...il.com>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, Leah Rumancik <leah.rumancik@...il.com>
Subject: [PATCH 1/2] ext4: wipe filename upon file deletion
Zero out filename field when file is deleted. Also, add mount option
nowipe_filename to disable this filename wipeout if desired.
Signed-off-by: Leah Rumancik <leah.rumancik@...il.com>
---
fs/ext4/ext4.h | 1 +
fs/ext4/namei.c | 4 ++++
fs/ext4/super.c | 11 ++++++++++-
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 826a56e3bbd2..8011418176bc 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1247,6 +1247,7 @@ struct ext4_inode_info {
#define EXT4_MOUNT2_JOURNAL_FAST_COMMIT 0x00000010 /* Journal fast commit */
#define EXT4_MOUNT2_DAX_NEVER 0x00000020 /* Do not allow Direct Access */
#define EXT4_MOUNT2_DAX_INODE 0x00000040 /* For printing options only */
+#define EXT4_MOUNT2_WIPE_FILENAME 0x00000080 /* Wipe filename on del entry */
#define clear_opt(sb, opt) EXT4_SB(sb)->s_mount_opt &= \
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 883e2a7cd4ab..ae6ecabd4d97 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2492,6 +2492,10 @@ int ext4_generic_delete_entry(struct inode *dir,
else
de->inode = 0;
inode_inc_iversion(dir);
+
+ if (test_opt2(dir->i_sb, WIPE_FILENAME))
+ memset(de_del->name, 0, de_del->name_len);
+
return 0;
}
i += ext4_rec_len_from_disk(de->rec_len, blocksize);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index b9693680463a..5e8737b3f171 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1688,7 +1688,7 @@ enum {
Opt_dioread_nolock, Opt_dioread_lock,
Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
Opt_max_dir_size_kb, Opt_nojournal_checksum, Opt_nombcache,
- Opt_prefetch_block_bitmaps,
+ Opt_prefetch_block_bitmaps, Opt_nowipe_filename,
#ifdef CONFIG_EXT4_DEBUG
Opt_fc_debug_max_replay, Opt_fc_debug_force
#endif
@@ -1787,6 +1787,7 @@ static const match_table_t tokens = {
{Opt_test_dummy_encryption, "test_dummy_encryption"},
{Opt_inlinecrypt, "inlinecrypt"},
{Opt_nombcache, "nombcache"},
+ {Opt_nowipe_filename, "nowipe_filename"},
{Opt_nombcache, "no_mbcache"}, /* for backward compatibility */
{Opt_prefetch_block_bitmaps, "prefetch_block_bitmaps"},
{Opt_removed, "check=none"}, /* mount option from ext2/3 */
@@ -2007,6 +2008,8 @@ static const struct mount_opts {
{Opt_max_dir_size_kb, 0, MOPT_GTE0},
{Opt_test_dummy_encryption, 0, MOPT_STRING},
{Opt_nombcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
+ {Opt_nowipe_filename, EXT4_MOUNT2_WIPE_FILENAME, MOPT_CLEAR | MOPT_2 |
+ MOPT_EXT4_ONLY},
{Opt_prefetch_block_bitmaps, EXT4_MOUNT_PREFETCH_BLOCK_BITMAPS,
MOPT_SET},
#ifdef CONFIG_EXT4_DEBUG
@@ -2621,6 +2624,10 @@ static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
} else if (test_opt2(sb, DAX_INODE)) {
SEQ_OPTS_PUTS("dax=inode");
}
+
+ if (!test_opt2(sb, WIPE_FILENAME))
+ SEQ_OPTS_PUTS("nowipe_filename");
+
ext4_show_quota_options(seq, sb);
return 0;
}
@@ -4161,6 +4168,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
if (def_mount_opts & EXT4_DEFM_DISCARD)
set_opt(sb, DISCARD);
+ set_opt2(sb, WIPE_FILENAME);
+
sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
--
2.31.0.291.g576ba9dcdaf-goog
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