[PATCH v8 0/8] Support for Casefolding and Encryption

[PATCH v8 0/8] Support for Casefolding and Encryption

[Daniel Rosenberg]

These patches are all on top of torvalds/master

Ext4 and F2FS currently both support casefolding and encryption, but not at
the same time. These patches aim to rectify that.

I've left off the Ext4 patches that enable casefolding and ecryption from
this revision since they still need some fixups, and I haven't gotten around
to the fsck changes yet.

I moved the identical casefolding dcache operations for ext4 and f2fs into
fs/libfs.c, as all filesystems using casefolded names will want them.

I've also adjust fscrypt to not set it's d_revalidate operation during it's
prepare lookup, instead having the calling filesystem set it up. This is
done to that the filesystem may have it's own dentry_operations. Also added
a helper function in libfs.c that will work for filesystems supporting both
casefolding and fscrypt.

For Ext4, since the hash for encrypted casefolded directory names cannot be
computed without the key, we need to store the hash on disk. We only do so
for encrypted and casefolded directories to avoid on disk format changes.
Previously encryption and casefolding could not be on the same filesystem,
and we're relaxing that requirement. F2fs is a bit more straightforward
since it already stores hashes on disk.

I've updated the related tools with just enough to enable the feature. I
still need to adjust ext4's fsck's, although without access to the keys,
neither fsck will be able to verify the hashes of casefolded and encrypted
names.

v8 changes:
Fixed issue with non-strict_mode fallback for hashing dentry op
Fixed potential RCU/unicode issue in casefolding dentry_ops.
Split "fscrypt: Have filesystems handle their d_ops" into a few smaller patches
Switched ubifs change to also use the dentry op function added in libfs.c
Added hash function in fs/unicode
changed super_block s_encoding_flags to u16. Didn't make unsigned int since
both filesystems using them use them as 16 bits, and want to avoid possible
confusion. Wouldn't really be opposed to that change though
Added kernel doc comments
misc other small adjustments
TODO:
 Investigate moving to a dentry flag to check for casefolding, or otherwise
 conditionally setting the casefolding dentry ops as needed, like fscrypt.
 Currently not done due to some issues with cached negative dentries and
 toggling casefolding on an empty directory.

 Ext4 fsck changes/debugging ext4 patches


v7 changes:
Moved dentry operations from unicode to libfs, added new iterator function
to unicode to allow this.
Added libfs function for setting dentries to remove code duplication between
ext4 and f2fs.

v6 changes:
Went back to using dentry_operations for casefolding. Provided standard
implementations in fs/unicode, avoiding extra allocation in d_hash op.
Moved fscrypt d_ops setting to be filesystem's responsibility to maintain
compatibility with casefolding and overlayfs if casefolding is not used
fixes some f2fs error handling

v4-5: patches submitted on fscrypt

v3 changes:
fscrypt patch only creates hash key if it will be needed.
Rebased on top of fscrypt branch, reconstified match functions in ext4/f2fs

v2 changes:
fscrypt moved to separate thread to rebase on fscrypt dev branch
addressed feedback, plus some minor fixes

Daniel Rosenberg (8):
  unicode: Add utf8_casefold_hash
  fs: Add standard casefolding support
  f2fs: Use generic casefolding support
  ext4: Use generic casefolding support
  fscrypt: Export fscrypt_d_revalidate
  libfs: Add generic function for setting dentry_ops
  fscrypt: Have filesystems handle their d_ops
  f2fs: Handle casefolding with Encryption

 fs/crypto/fname.c           |   7 +-
 fs/crypto/fscrypt_private.h |   1 -
 fs/crypto/hooks.c           |   1 -
 fs/ext4/dir.c               |  51 -----------
 fs/ext4/ext4.h              |  16 ----
 fs/ext4/hash.c              |   2 +-
 fs/ext4/namei.c             |  21 ++---
 fs/ext4/super.c             |  15 ++--
 fs/f2fs/dir.c               | 127 +++++++++++-----------------
 fs/f2fs/f2fs.h              |  18 +---
 fs/f2fs/hash.c              |  27 ++++--
 fs/f2fs/inline.c            |   9 +-
 fs/f2fs/namei.c             |   1 +
 fs/f2fs/super.c             |  17 ++--
 fs/f2fs/sysfs.c             |  10 ++-
 fs/libfs.c                  | 164 ++++++++++++++++++++++++++++++++++++
 fs/ubifs/dir.c              |   1 +
 fs/unicode/utf8-core.c      |  23 ++++-
 include/linux/f2fs_fs.h     |   3 -
 include/linux/fs.h          |  24 ++++++
 include/linux/fscrypt.h     |   6 +-
 include/linux/unicode.h     |   3 +
 22 files changed, 321 insertions(+), 226 deletions(-)

-- 
2.25.1.481.gfbce0eb801-goog

[PATCH v8 1/8] unicode: Add utf8_casefold_hash

[Daniel Rosenberg]

This adds a case insensitive hash function to allow taking the hash
without needing to allocate a casefolded copy of the string.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/unicode/utf8-core.c  | 23 ++++++++++++++++++++++-
 include/linux/unicode.h |  3 +++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/fs/unicode/utf8-core.c b/fs/unicode/utf8-core.c
index 2a878b739115d..90656b9980720 100644
--- a/fs/unicode/utf8-core.c
+++ b/fs/unicode/utf8-core.c
@@ -6,6 +6,7 @@
 #include <linux/parser.h>
 #include <linux/errno.h>
 #include <linux/unicode.h>
+#include <linux/stringhash.h>
 
 #include "utf8n.h"
 
@@ -122,9 +123,29 @@ int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
 	}
 	return -EINVAL;
 }
-
 EXPORT_SYMBOL(utf8_casefold);
 
+int utf8_casefold_hash(const struct unicode_map *um, const void *salt,
+		       struct qstr *str)
+{
+	const struct utf8data *data = utf8nfdicf(um->version);
+	struct utf8cursor cur;
+	int c;
+	unsigned long hash = init_name_hash(salt);
+
+	if (utf8ncursor(&cur, data, str->name, str->len) < 0)
+		return -EINVAL;
+
+	while ((c = utf8byte(&cur))) {
+		if (c < 0)
+			return c;
+		hash = partial_name_hash((unsigned char)c, hash);
+	}
+	str->hash = end_name_hash(hash);
+	return 0;
+}
+EXPORT_SYMBOL(utf8_casefold_hash);
+
 int utf8_normalize(const struct unicode_map *um, const struct qstr *str,
 		   unsigned char *dest, size_t dlen)
 {
diff --git a/include/linux/unicode.h b/include/linux/unicode.h
index 990aa97d80496..74484d44c7554 100644
--- a/include/linux/unicode.h
+++ b/include/linux/unicode.h
@@ -27,6 +27,9 @@ int utf8_normalize(const struct unicode_map *um, const struct qstr *str,
 int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
 		  unsigned char *dest, size_t dlen);
 
+int utf8_casefold_hash(const struct unicode_map *um, const void *salt,
+		       struct qstr *str);
+
 struct unicode_map *utf8_load(const char *version);
 void utf8_unload(struct unicode_map *um);
 
-- 
2.25.1.481.gfbce0eb801-goog

[PATCH v8 2/8] fs: Add standard casefolding support

[Daniel Rosenberg]

This adds general supporting functions for filesystems that use
utf8 casefolding. It provides standard dentry_operations and adds the
necessary structures in struct super_block to allow this standardization.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/libfs.c         | 114 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h |  22 +++++++++
 2 files changed, 136 insertions(+)

diff --git a/fs/libfs.c b/fs/libfs.c
index c686bd9caac67..0eaa63a9ae037 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -20,6 +20,8 @@
 #include <linux/fs_context.h>
 #include <linux/pseudo_fs.h>
 #include <linux/fsnotify.h>
+#include <linux/unicode.h>
+#include <linux/fscrypt.h>
 
 #include <linux/uaccess.h>
 
@@ -1361,3 +1363,115 @@ bool is_empty_dir_inode(struct inode *inode)
 	return (inode->i_fop == &empty_dir_operations) &&
 		(inode->i_op == &empty_dir_inode_operations);
 }
+
+#ifdef CONFIG_UNICODE
+/**
+ * needs_casefold - determine if casefolding applies for a given directory
+ * @dir:	Folder to check
+ *
+ * This function returns true if dentries within this folder should be
+ * casefolded. If a folder is encrypted, but we don't have the key, it is not
+ * meaningful to casefold the no-key token name.
+ */
+bool needs_casefold(const struct inode *dir)
+{
+	return IS_CASEFOLDED(dir) && dir->i_sb->s_encoding &&
+			(!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir));
+}
+EXPORT_SYMBOL(needs_casefold);
+
+/*
+ * Under RCU, small names may change, but utf8 expects a stable name
+ * This operates similarly to take_dentry_name_snapshot, except that there
+ * is no guarantee that it grabs a coherent string.
+ */
+static int make_name_stable(const struct unicode_map *um,
+			   const struct dentry *dentry, struct qstr *entry,
+			   char *buff)
+{
+	if (dentry->d_iname != (const unsigned char *)entry->name)
+		return 0;
+
+	memcpy(buff, entry->name, entry->len + 1);
+	entry->name = buff;
+	return utf8_validate(um, entry);
+}
+
+/**
+ * generic_ci_d_compare - generic implementation of d_compare for casefolding
+ * @dentry: Entry we are comparing against
+ * @len: length of str
+ * @str: name of the dentry, safely paired with len
+ * @name: qstr to test against
+ *
+ * This performs a case insensitive comparison between the given name and str.
+ * It can be used as d_compare for dentry_operations.
+ */
+int generic_ci_d_compare(const struct dentry *dentry, unsigned int len,
+			  const char *str, const struct qstr *name)
+{
+	const struct dentry *parent = READ_ONCE(dentry->d_parent);
+	const struct inode *inode = READ_ONCE(parent->d_inode);
+	const struct super_block *sb = dentry->d_sb;
+	const struct unicode_map *um = sb->s_encoding;
+	char small_name[DNAME_INLINE_LEN];
+	struct qstr entry = QSTR_INIT(str, len);
+	int ret;
+
+	if (!inode || !needs_casefold(inode))
+		goto fallback;
+
+	/* Under RCU, small names may change, but utf8 expects a stable name */
+	if (make_name_stable(um, dentry, &entry, small_name))
+		goto err;
+	ret = utf8_strncasecmp(um, name, &entry);
+	if (ret >= 0)
+		return ret;
+err:
+	if (sb_has_enc_strict_mode(sb))
+		return -EINVAL;
+fallback:
+	if (len != name->len)
+		return 1;
+	return !!memcmp(str, name->name, len);
+}
+EXPORT_SYMBOL(generic_ci_d_compare);
+
+/**
+ * generic_ci_d_hash - generic implementation of d_hash for casefolding
+ * @dentry: Entry whose name we are hashing
+ * @len: length of str
+ * @qstr: name of the dentry, safely paired with len
+ * @str: qstr to set hash of
+ *
+ * This performs a case insensitive hash of the given str.
+ * If casefolding is not required, it leaves the hash unchanged.
+ */
+int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str)
+{
+	const struct inode *inode = READ_ONCE(dentry->d_inode);
+	struct super_block *sb = dentry->d_sb;
+	const struct unicode_map *um = sb->s_encoding;
+	char small_name[DNAME_INLINE_LEN];
+	struct qstr entry = QSTR_INIT(str->name, str->len);
+	int ret = 0;
+
+	if (!inode || !needs_casefold(inode))
+		return 0;
+
+	if (make_name_stable(um, dentry, &entry, small_name))
+		goto err;
+	ret = utf8_casefold_hash(um, dentry, &entry);
+	if (ret < 0)
+		goto err;
+
+	return 0;
+err:
+	if (sb_has_enc_strict_mode(sb))
+		ret = -EINVAL;
+	else
+		ret = 0;
+	return ret;
+}
+EXPORT_SYMBOL(generic_ci_d_hash);
+#endif
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3cd4fe6b845e7..8d20a3daa49a0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1382,6 +1382,12 @@ extern int send_sigurg(struct fown_struct *fown);
 #define SB_ACTIVE	(1<<30)
 #define SB_NOUSER	(1<<31)
 
+/* These flags relate to encoding and casefolding, and are stored on disk */
+#define SB_ENC_STRICT_MODE_FL	(1 << 0)
+
+#define sb_has_enc_strict_mode(sb) \
+	(sb->s_encoding_flags & SB_ENC_STRICT_MODE_FL)
+
 /*
  *	Umount options
  */
@@ -1449,6 +1455,10 @@ struct super_block {
 #endif
 #ifdef CONFIG_FS_VERITY
 	const struct fsverity_operations *s_vop;
+#endif
+#ifdef CONFIG_UNICODE
+	struct unicode_map *s_encoding;
+	u16 s_encoding_flags;
 #endif
 	struct hlist_bl_head	s_roots;	/* alternate root dentries for NFS */
 	struct list_head	s_mounts;	/* list of mounts; _not_ for fs use */
@@ -3368,6 +3378,18 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
 
 extern int generic_check_addressable(unsigned, u64);
 
+#ifdef CONFIG_UNICODE
+extern int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str);
+extern int generic_ci_d_compare(const struct dentry *dentry, unsigned int len,
+				const char *str, const struct qstr *name);
+extern bool needs_casefold(const struct inode *dir);
+#else
+static inline bool needs_casefold(const struct inode *dir)
+{
+	return false;
+}
+#endif
+
 #ifdef CONFIG_MIGRATION
 extern int buffer_migrate_page(struct address_space *,
 				struct page *, struct page *,
-- 
2.25.1.481.gfbce0eb801-goog

[PATCH v8 3/8] f2fs: Use generic casefolding support

[Daniel Rosenberg]

This switches f2fs over to the generic casefolded support provided in
the previous patch

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/f2fs/dir.c           | 63 +++++++----------------------------------
 fs/f2fs/f2fs.h          |  4 ---
 fs/f2fs/hash.c          |  2 +-
 fs/f2fs/super.c         | 10 +++----
 fs/f2fs/sysfs.c         | 10 ++++---
 include/linux/f2fs_fs.h |  3 --
 6 files changed, 22 insertions(+), 70 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 27d0dd7a16d6d..d822c0d5eb182 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -114,8 +114,8 @@ static struct f2fs_dir_entry *find_in_block(struct inode *dir,
 int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,
 				const struct qstr *entry, bool quick)
 {
-	const struct f2fs_sb_info *sbi = F2FS_SB(parent->i_sb);
-	const struct unicode_map *um = sbi->s_encoding;
+	const struct super_block *sb = parent->i_sb;
+	const struct unicode_map *um = sb->s_encoding;
 	int ret;
 
 	if (quick)
@@ -127,7 +127,7 @@ int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,
 		/* Handle invalid character sequence as either an error
 		 * or as an opaque byte sequence.
 		 */
-		if (f2fs_has_strict_mode(sbi))
+		if (sb_has_enc_strict_mode(sb))
 			return -EINVAL;
 
 		if (name->len != entry->len)
@@ -154,7 +154,7 @@ static void f2fs_fname_setup_ci_filename(struct inode *dir,
 	if (!cf_name->name)
 		return;
 
-	cf_name->len = utf8_casefold(sbi->s_encoding,
+	cf_name->len = utf8_casefold(dir->i_sb->s_encoding,
 					iname, cf_name->name,
 					F2FS_NAME_LEN);
 	if ((int)cf_name->len <= 0) {
@@ -173,7 +173,7 @@ static inline bool f2fs_match_name(struct f2fs_dentry_ptr *d,
 {
 #ifdef CONFIG_UNICODE
 	struct inode *parent = d->inode;
-	struct f2fs_sb_info *sbi = F2FS_I_SB(parent);
+	struct super_block *sb = parent->i_sb;
 	struct qstr entry;
 #endif
 
@@ -184,7 +184,7 @@ static inline bool f2fs_match_name(struct f2fs_dentry_ptr *d,
 	entry.name = d->filename[bit_pos];
 	entry.len = de->name_len;
 
-	if (sbi->s_encoding && IS_CASEFOLDED(parent)) {
+	if (sb->s_encoding && IS_CASEFOLDED(parent)) {
 		if (cf_str->name) {
 			struct qstr cf = {.name = cf_str->name,
 					  .len = cf_str->len};
@@ -357,8 +357,8 @@ struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 	int err;
 
 #ifdef CONFIG_UNICODE
-	if (f2fs_has_strict_mode(F2FS_I_SB(dir)) && IS_CASEFOLDED(dir) &&
-			utf8_validate(F2FS_I_SB(dir)->s_encoding, child)) {
+	if (sb_has_enc_strict_mode(dir->i_sb) && IS_CASEFOLDED(dir) &&
+			utf8_validate(dir->i_sb->s_encoding, child)) {
 		*res_page = ERR_PTR(-EINVAL);
 		return NULL;
 	}
@@ -1079,51 +1079,8 @@ const struct file_operations f2fs_dir_operations = {
 };
 
 #ifdef CONFIG_UNICODE
-static int f2fs_d_compare(const struct dentry *dentry, unsigned int len,
-			  const char *str, const struct qstr *name)
-{
-	struct qstr qstr = {.name = str, .len = len };
-	const struct dentry *parent = READ_ONCE(dentry->d_parent);
-	const struct inode *inode = READ_ONCE(parent->d_inode);
-
-	if (!inode || !IS_CASEFOLDED(inode)) {
-		if (len != name->len)
-			return -1;
-		return memcmp(str, name->name, len);
-	}
-
-	return f2fs_ci_compare(inode, name, &qstr, false);
-}
-
-static int f2fs_d_hash(const struct dentry *dentry, struct qstr *str)
-{
-	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
-	const struct unicode_map *um = sbi->s_encoding;
-	const struct inode *inode = READ_ONCE(dentry->d_inode);
-	unsigned char *norm;
-	int len, ret = 0;
-
-	if (!inode || !IS_CASEFOLDED(inode))
-		return 0;
-
-	norm = f2fs_kmalloc(sbi, PATH_MAX, GFP_ATOMIC);
-	if (!norm)
-		return -ENOMEM;
-
-	len = utf8_casefold(um, str, norm, PATH_MAX);
-	if (len < 0) {
-		if (f2fs_has_strict_mode(sbi))
-			ret = -EINVAL;
-		goto out;
-	}
-	str->hash = full_name_hash(dentry, norm, len);
-out:
-	kvfree(norm);
-	return ret;
-}
-
 const struct dentry_operations f2fs_dentry_ops = {
-	.d_hash = f2fs_d_hash,
-	.d_compare = f2fs_d_compare,
+	.d_hash = generic_ci_d_hash,
+	.d_compare = generic_ci_d_compare,
 };
 #endif
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 5355be6b6755c..e73b8752f9c8d 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1284,10 +1284,6 @@ struct f2fs_sb_info {
 	int valid_super_block;			/* valid super block no */
 	unsigned long s_flag;				/* flags for sbi */
 	struct mutex writepages;		/* mutex for writepages() */
-#ifdef CONFIG_UNICODE
-	struct unicode_map *s_encoding;
-	__u16 s_encoding_flags;
-#endif
 
 #ifdef CONFIG_BLK_DEV_ZONED
 	unsigned int blocks_per_blkz;		/* F2FS blocks per zone */
diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
index 5bc4dcd8fc03f..28acb24e7a7a8 100644
--- a/fs/f2fs/hash.c
+++ b/fs/f2fs/hash.c
@@ -110,7 +110,7 @@ f2fs_hash_t f2fs_dentry_hash(const struct inode *dir,
 {
 #ifdef CONFIG_UNICODE
 	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
-	const struct unicode_map *um = sbi->s_encoding;
+	const struct unicode_map *um = dir->i_sb->s_encoding;
 	int r, dlen;
 	unsigned char *buff;
 	struct qstr folded;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 65a7a432dfee2..89b52629bd437 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1213,7 +1213,7 @@ static void f2fs_put_super(struct super_block *sb)
 	for (i = 0; i < NR_PAGE_TYPE; i++)
 		kvfree(sbi->write_io[i]);
 #ifdef CONFIG_UNICODE
-	utf8_unload(sbi->s_encoding);
+	utf8_unload(sb->s_encoding);
 #endif
 	kvfree(sbi);
 }
@@ -3223,7 +3223,7 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 static int f2fs_setup_casefold(struct f2fs_sb_info *sbi)
 {
 #ifdef CONFIG_UNICODE
-	if (f2fs_sb_has_casefold(sbi) && !sbi->s_encoding) {
+	if (f2fs_sb_has_casefold(sbi) && !sbi->sb->s_encoding) {
 		const struct f2fs_sb_encodings *encoding_info;
 		struct unicode_map *encoding;
 		__u16 encoding_flags;
@@ -3254,8 +3254,8 @@ static int f2fs_setup_casefold(struct f2fs_sb_info *sbi)
 			 "%s-%s with flags 0x%hx", encoding_info->name,
 			 encoding_info->version?:"\b", encoding_flags);
 
-		sbi->s_encoding = encoding;
-		sbi->s_encoding_flags = encoding_flags;
+		sbi->sb->s_encoding = encoding;
+		sbi->sb->s_encoding_flags = encoding_flags;
 		sbi->sb->s_d_op = &f2fs_dentry_ops;
 	}
 #else
@@ -3742,7 +3742,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		kvfree(sbi->write_io[i]);
 
 #ifdef CONFIG_UNICODE
-	utf8_unload(sbi->s_encoding);
+	utf8_unload(sb->s_encoding);
 #endif
 free_options:
 #ifdef CONFIG_QUOTA
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 91d649790b1bc..4e8aae03f26c1 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -175,12 +175,14 @@ static ssize_t encoding_show(struct f2fs_attr *a,
 		struct f2fs_sb_info *sbi, char *buf)
 {
 #ifdef CONFIG_UNICODE
+	struct super_block *sb = sbi->sb;
+
 	if (f2fs_sb_has_casefold(sbi))
 		return snprintf(buf, PAGE_SIZE, "%s (%d.%d.%d)\n",
-			sbi->s_encoding->charset,
-			(sbi->s_encoding->version >> 16) & 0xff,
-			(sbi->s_encoding->version >> 8) & 0xff,
-			sbi->s_encoding->version & 0xff);
+			sb->s_encoding->charset,
+			(sb->s_encoding->version >> 16) & 0xff,
+			(sb->s_encoding->version >> 8) & 0xff,
+			sb->s_encoding->version & 0xff);
 #endif
 	return sprintf(buf, "(none)");
 }
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index ac3f4888b3dfa..e8763a955f90d 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -38,9 +38,6 @@
 #define F2FS_MAX_QUOTAS		3
 
 #define F2FS_ENC_UTF8_12_1	1
-#define F2FS_ENC_STRICT_MODE_FL	(1 << 0)
-#define f2fs_has_strict_mode(sbi) \
-	(sbi->s_encoding_flags & F2FS_ENC_STRICT_MODE_FL)
 
 #define F2FS_IO_SIZE(sbi)	(1 << F2FS_OPTION(sbi).write_io_size_bits) /* Blocks */
 #define F2FS_IO_SIZE_KB(sbi)	(1 << (F2FS_OPTION(sbi).write_io_size_bits + 2)) /* KB */
-- 
2.25.1.481.gfbce0eb801-goog

[PATCH v8 4/8] ext4: Use generic casefolding support

[Daniel Rosenberg]

This switches ext4 over to the generic casefolding support provided by
the previous patch.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/ext4/dir.c   | 48 ++----------------------------------------------
 fs/ext4/ext4.h  | 12 ------------
 fs/ext4/hash.c  |  2 +-
 fs/ext4/namei.c | 20 ++++++++------------
 fs/ext4/super.c | 12 ++++++------
 5 files changed, 17 insertions(+), 77 deletions(-)

diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 9aa1f75409b02..04fd68c4adc5f 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -669,52 +669,8 @@ const struct file_operations ext4_dir_operations = {
 };
 
 #ifdef CONFIG_UNICODE
-static int ext4_d_compare(const struct dentry *dentry, unsigned int len,
-			  const char *str, const struct qstr *name)
-{
-	struct qstr qstr = {.name = str, .len = len };
-	const struct dentry *parent = READ_ONCE(dentry->d_parent);
-	const struct inode *inode = READ_ONCE(parent->d_inode);
-
-	if (!inode || !IS_CASEFOLDED(inode) ||
-	    !EXT4_SB(inode->i_sb)->s_encoding) {
-		if (len != name->len)
-			return -1;
-		return memcmp(str, name->name, len);
-	}
-
-	return ext4_ci_compare(inode, name, &qstr, false);
-}
-
-static int ext4_d_hash(const struct dentry *dentry, struct qstr *str)
-{
-	const struct ext4_sb_info *sbi = EXT4_SB(dentry->d_sb);
-	const struct unicode_map *um = sbi->s_encoding;
-	const struct inode *inode = READ_ONCE(dentry->d_inode);
-	unsigned char *norm;
-	int len, ret = 0;
-
-	if (!inode || !IS_CASEFOLDED(inode) || !um)
-		return 0;
-
-	norm = kmalloc(PATH_MAX, GFP_ATOMIC);
-	if (!norm)
-		return -ENOMEM;
-
-	len = utf8_casefold(um, str, norm, PATH_MAX);
-	if (len < 0) {
-		if (ext4_has_strict_mode(sbi))
-			ret = -EINVAL;
-		goto out;
-	}
-	str->hash = full_name_hash(dentry, norm, len);
-out:
-	kfree(norm);
-	return ret;
-}
-
 const struct dentry_operations ext4_dentry_ops = {
-	.d_hash = ext4_d_hash,
-	.d_compare = ext4_d_compare,
+	.d_hash = generic_ci_d_hash,
+	.d_compare = generic_ci_d_compare,
 };
 #endif
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 61b37a052052b..b912c5611ddad 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1372,14 +1372,6 @@ struct ext4_super_block {
 
 #define EXT4_ENC_UTF8_12_1	1
 
-/*
- * Flags for ext4_sb_info.s_encoding_flags.
- */
-#define EXT4_ENC_STRICT_MODE_FL	(1 << 0)
-
-#define ext4_has_strict_mode(sbi) \
-	(sbi->s_encoding_flags & EXT4_ENC_STRICT_MODE_FL)
-
 /*
  * fourth extended-fs super-block data in memory
  */
@@ -1429,10 +1421,6 @@ struct ext4_sb_info {
 	struct kobject s_kobj;
 	struct completion s_kobj_unregister;
 	struct super_block *s_sb;
-#ifdef CONFIG_UNICODE
-	struct unicode_map *s_encoding;
-	__u16 s_encoding_flags;
-#endif
 
 	/* Journaling */
 	struct journal_s *s_journal;
diff --git a/fs/ext4/hash.c b/fs/ext4/hash.c
index 3e133793a5a34..143b0073b3f46 100644
--- a/fs/ext4/hash.c
+++ b/fs/ext4/hash.c
@@ -275,7 +275,7 @@ int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
 		   struct dx_hash_info *hinfo)
 {
 #ifdef CONFIG_UNICODE
-	const struct unicode_map *um = EXT4_SB(dir->i_sb)->s_encoding;
+	const struct unicode_map *um = dir->i_sb->s_encoding;
 	int r, dlen;
 	unsigned char *buff;
 	struct qstr qstr = {.name = name, .len = len };
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index b05ea72f38fd1..1a1c4fdcfd3ee 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1286,8 +1286,8 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
 int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
 		    const struct qstr *entry, bool quick)
 {
-	const struct ext4_sb_info *sbi = EXT4_SB(parent->i_sb);
-	const struct unicode_map *um = sbi->s_encoding;
+	const struct super_block *sb = parent->i_sb;
+	const struct unicode_map *um = sb->s_encoding;
 	int ret;
 
 	if (quick)
@@ -1299,7 +1299,7 @@ int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
 		/* Handle invalid character sequence as either an error
 		 * or as an opaque byte sequence.
 		 */
-		if (ext4_has_strict_mode(sbi))
+		if (sb_has_enc_strict_mode(sb))
 			return -EINVAL;
 
 		if (name->len != entry->len)
@@ -1316,7 +1316,7 @@ void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
 {
 	int len;
 
-	if (!IS_CASEFOLDED(dir) || !EXT4_SB(dir->i_sb)->s_encoding) {
+	if (!needs_casefold(dir)) {
 		cf_name->name = NULL;
 		return;
 	}
@@ -1325,7 +1325,7 @@ void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
 	if (!cf_name->name)
 		return;
 
-	len = utf8_casefold(EXT4_SB(dir->i_sb)->s_encoding,
+	len = utf8_casefold(dir->i_sb->s_encoding,
 			    iname, cf_name->name,
 			    EXT4_NAME_LEN);
 	if (len <= 0) {
@@ -1362,7 +1362,7 @@ static inline bool ext4_match(const struct inode *parent,
 #endif
 
 #ifdef CONFIG_UNICODE
-	if (EXT4_SB(parent->i_sb)->s_encoding && IS_CASEFOLDED(parent)) {
+	if (needs_casefold(parent)) {
 		if (fname->cf_name.name) {
 			struct qstr cf = {.name = fname->cf_name.name,
 					  .len = fname->cf_name.len};
@@ -2171,9 +2171,6 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
 	struct buffer_head *bh = NULL;
 	struct ext4_dir_entry_2 *de;
 	struct super_block *sb;
-#ifdef CONFIG_UNICODE
-	struct ext4_sb_info *sbi;
-#endif
 	struct ext4_filename fname;
 	int	retval;
 	int	dx_fallback=0;
@@ -2190,9 +2187,8 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
 		return -EINVAL;
 
 #ifdef CONFIG_UNICODE
-	sbi = EXT4_SB(sb);
-	if (ext4_has_strict_mode(sbi) && IS_CASEFOLDED(dir) &&
-	    sbi->s_encoding && utf8_validate(sbi->s_encoding, &dentry->d_name))
+	if (sb_has_enc_strict_mode(sb) && IS_CASEFOLDED(dir) &&
+	    sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))
 		return -EINVAL;
 #endif
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 0c7c4adb664ec..11a7af11d8aee 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1112,7 +1112,7 @@ static void ext4_put_super(struct super_block *sb)
 	kfree(sbi->s_blockgroup_lock);
 	fs_put_dax(sbi->s_daxdev);
 #ifdef CONFIG_UNICODE
-	utf8_unload(sbi->s_encoding);
+	utf8_unload(sb->s_encoding);
 #endif
 	kfree(sbi);
 }
@@ -3926,7 +3926,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount;
 
 #ifdef CONFIG_UNICODE
-	if (ext4_has_feature_casefold(sb) && !sbi->s_encoding) {
+	if (ext4_has_feature_casefold(sb) && !sb->s_encoding) {
 		const struct ext4_sb_encodings *encoding_info;
 		struct unicode_map *encoding;
 		__u16 encoding_flags;
@@ -3957,8 +3957,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 			 "%s-%s with flags 0x%hx", encoding_info->name,
 			 encoding_info->version?:"\b", encoding_flags);
 
-		sbi->s_encoding = encoding;
-		sbi->s_encoding_flags = encoding_flags;
+		sb->s_encoding = encoding;
+		sb->s_encoding_flags = encoding_flags;
 	}
 #endif
 
@@ -4571,7 +4571,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 #ifdef CONFIG_UNICODE
-	if (sbi->s_encoding)
+	if (sb->s_encoding)
 		sb->s_d_op = &ext4_dentry_ops;
 #endif
 
@@ -4766,7 +4766,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		crypto_free_shash(sbi->s_chksum_driver);
 
 #ifdef CONFIG_UNICODE
-	utf8_unload(sbi->s_encoding);
+	utf8_unload(sb->s_encoding);
 #endif
 
 #ifdef CONFIG_QUOTA
-- 
2.25.1.481.gfbce0eb801-goog

[PATCH v8 5/8] fscrypt: Export fscrypt_d_revalidate

[Daniel Rosenberg]

This is in preparation for shifting the responsibility of setting the
dentry_operations to the filesystem, allowing it to maintain its own
operations.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/crypto/fname.c       | 3 ++-
 include/linux/fscrypt.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 4c212442a8f7f..73adbbb9d78c7 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -543,7 +543,7 @@ EXPORT_SYMBOL_GPL(fscrypt_fname_siphash);
  * Validate dentries in encrypted directories to make sure we aren't potentially
  * caching stale dentries after a key has been added.
  */
-static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
+int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 {
 	struct dentry *dir;
 	int err;
@@ -586,3 +586,4 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 const struct dentry_operations fscrypt_d_ops = {
 	.d_revalidate = fscrypt_d_revalidate,
 };
+EXPORT_SYMBOL(fscrypt_d_revalidate);
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 556f4adf5dc58..b199b6e976ce3 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -176,6 +176,7 @@ extern bool fscrypt_match_name(const struct fscrypt_name *fname,
 			       const u8 *de_name, u32 de_name_len);
 extern u64 fscrypt_fname_siphash(const struct inode *dir,
 				 const struct qstr *name);
+extern int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags);
 
 /* bio.c */
 extern void fscrypt_decrypt_bio(struct bio *);
-- 
2.25.1.481.gfbce0eb801-goog

[PATCH v8 6/8] libfs: Add generic function for setting dentry_ops

[Daniel Rosenberg]

This adds a function to set dentry operations at lookup time that will
work for both encrypted files and casefolded filenames.

A filesystem that supports both features simultaneously can use this
function during lookup preperations to set up its dentry operations once
fscrypt no longer does that itself.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/libfs.c         | 50 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h |  2 ++
 2 files changed, 52 insertions(+)

diff --git a/fs/libfs.c b/fs/libfs.c
index 0eaa63a9ae037..bdda03c8ece9e 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1474,4 +1474,54 @@ int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str)
 	return ret;
 }
 EXPORT_SYMBOL(generic_ci_d_hash);
+
+static const struct dentry_operations generic_ci_dentry_ops = {
+	.d_hash = generic_ci_d_hash,
+	.d_compare = generic_ci_d_compare,
+};
+#endif
+
+#ifdef CONFIG_FS_ENCRYPTION
+static const struct dentry_operations generic_encrypted_dentry_ops = {
+	.d_revalidate = fscrypt_d_revalidate,
+};
+#endif
+
+#if IS_ENABLED(CONFIG_UNICODE) && IS_ENABLED(CONFIG_FS_ENCRYPTION)
+static const struct dentry_operations generic_encrypted_ci_dentry_ops = {
+	.d_hash = generic_ci_d_hash,
+	.d_compare = generic_ci_d_compare,
+	.d_revalidate = fscrypt_d_revalidate,
+};
+#endif
+
+/**
+ * generic_set_encrypted_ci_d_ops - helper for setting d_ops for given dentry
+ * @dir:	parent of dentry whose ops to set
+ * @dentry:	dentry to set ops on
+ *
+ * This function sets the dentry ops for the given dentry to handle both
+ * casefolding and encryption of the dentry name.
+ */
+void generic_set_encrypted_ci_d_ops(struct inode *dir, struct dentry *dentry)
+{
+#ifdef CONFIG_FS_ENCRYPTION
+	if (dentry->d_flags & DCACHE_ENCRYPTED_NAME) {
+#ifdef CONFIG_UNICODE
+		if (dir->i_sb->s_encoding) {
+			d_set_d_op(dentry, &generic_encrypted_ci_dentry_ops);
+			return;
+		}
 #endif
+		d_set_d_op(dentry, &generic_encrypted_dentry_ops);
+		return;
+	}
+#endif
+#ifdef CONFIG_UNICODE
+	if (dir->i_sb->s_encoding) {
+		d_set_d_op(dentry, &generic_ci_dentry_ops);
+		return;
+	}
+#endif
+}
+EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8d20a3daa49a0..dc433bc4f0602 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3389,6 +3389,8 @@ static inline bool needs_casefold(const struct inode *dir)
 	return false;
 }
 #endif
+extern void generic_set_encrypted_ci_d_ops(struct inode *dir,
+					   struct dentry *dentry);
 
 #ifdef CONFIG_MIGRATION
 extern int buffer_migrate_page(struct address_space *,
-- 
2.25.1.481.gfbce0eb801-goog

[PATCH v8 7/8] fscrypt: Have filesystems handle their d_ops

[Daniel Rosenberg]

This shifts the responsibility of setting up dentry operations from
fscrypt to the individual filesystems, allowing them to have their own
operations while still setting fscrypt's d_revalidate as appropriate.

Most filesystems can just use generic_set_encrypted_ci_d_ops, unless
they have their own specific dentry operations as well. That operation
will set the minimal d_ops required under the circumstances.

Since the fscrypt d_ops are set later on, we must set all d_ops there,
since we cannot adjust those later on. This should not result in any
change in behavior.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/crypto/fname.c           | 4 ----
 fs/crypto/fscrypt_private.h | 1 -
 fs/crypto/hooks.c           | 1 -
 fs/ext4/dir.c               | 7 -------
 fs/ext4/ext4.h              | 4 ----
 fs/ext4/namei.c             | 1 +
 fs/ext4/super.c             | 5 -----
 fs/f2fs/dir.c               | 7 -------
 fs/f2fs/f2fs.h              | 3 ---
 fs/f2fs/namei.c             | 1 +
 fs/f2fs/super.c             | 1 -
 fs/ubifs/dir.c              | 1 +
 include/linux/fscrypt.h     | 5 +++--
 13 files changed, 6 insertions(+), 35 deletions(-)

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 73adbbb9d78c7..14c585f66f8da 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -582,8 +582,4 @@ int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 
 	return valid;
 }
-
-const struct dentry_operations fscrypt_d_ops = {
-	.d_revalidate = fscrypt_d_revalidate,
-};
 EXPORT_SYMBOL(fscrypt_d_revalidate);
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 9aae851409e55..238075fcabb3e 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -250,7 +250,6 @@ extern int fscrypt_fname_encrypt(const struct inode *inode,
 extern bool fscrypt_fname_encrypted_size(const struct inode *inode,
 					 u32 orig_len, u32 max_len,
 					 u32 *encrypted_len_ret);
-extern const struct dentry_operations fscrypt_d_ops;
 
 /* hkdf.c */
 
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index 5ef861742921c..604a028dee25a 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -118,7 +118,6 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
 		spin_lock(&dentry->d_lock);
 		dentry->d_flags |= DCACHE_ENCRYPTED_NAME;
 		spin_unlock(&dentry->d_lock);
-		d_set_d_op(dentry, &fscrypt_d_ops);
 	}
 	return err;
 }
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 04fd68c4adc5f..b31780cae9c1f 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -667,10 +667,3 @@ const struct file_operations ext4_dir_operations = {
 	.open		= ext4_dir_open,
 	.release	= ext4_release_dir,
 };
-
-#ifdef CONFIG_UNICODE
-const struct dentry_operations ext4_dentry_ops = {
-	.d_hash = generic_ci_d_hash,
-	.d_compare = generic_ci_d_compare,
-};
-#endif
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b912c5611ddad..a01a507731d41 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3169,10 +3169,6 @@ static inline void ext4_unlock_group(struct super_block *sb,
 /* dir.c */
 extern const struct file_operations ext4_dir_operations;
 
-#ifdef CONFIG_UNICODE
-extern const struct dentry_operations ext4_dentry_ops;
-#endif
-
 /* file.c */
 extern const struct inode_operations ext4_file_inode_operations;
 extern const struct file_operations ext4_file_operations;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 1a1c4fdcfd3ee..001fdb0da477e 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1615,6 +1615,7 @@ static struct buffer_head *ext4_lookup_entry(struct inode *dir,
 	struct buffer_head *bh;
 
 	err = ext4_fname_prepare_lookup(dir, dentry, &fname);
+	generic_set_encrypted_ci_d_ops(dir, dentry);
 	if (err == -ENOENT)
 		return NULL;
 	if (err)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 11a7af11d8aee..c732122b25739 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4570,11 +4570,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount4;
 	}
 
-#ifdef CONFIG_UNICODE
-	if (sb->s_encoding)
-		sb->s_d_op = &ext4_dentry_ops;
-#endif
-
 	sb->s_root = d_make_root(root);
 	if (!sb->s_root) {
 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index d822c0d5eb182..38c0e6d589be4 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -1077,10 +1077,3 @@ const struct file_operations f2fs_dir_operations = {
 	.compat_ioctl   = f2fs_compat_ioctl,
 #endif
 };
-
-#ifdef CONFIG_UNICODE
-const struct dentry_operations f2fs_dentry_ops = {
-	.d_hash = generic_ci_d_hash,
-	.d_compare = generic_ci_d_compare,
-};
-#endif
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index e73b8752f9c8d..0fc153b5a5c09 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3626,9 +3626,6 @@ static inline void update_sit_info(struct f2fs_sb_info *sbi) {}
 #endif
 
 extern const struct file_operations f2fs_dir_operations;
-#ifdef CONFIG_UNICODE
-extern const struct dentry_operations f2fs_dentry_ops;
-#endif
 extern const struct file_operations f2fs_file_operations;
 extern const struct inode_operations f2fs_file_inode_operations;
 extern const struct address_space_operations f2fs_dblock_aops;
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 2aa035422c0fa..24d68eafffa40 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -494,6 +494,7 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 	}
 
 	err = fscrypt_prepare_lookup(dir, dentry, &fname);
+	generic_set_encrypted_ci_d_ops(dir, dentry);
 	if (err == -ENOENT)
 		goto out_splice;
 	if (err)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 89b52629bd437..7520a9c04c75e 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3256,7 +3256,6 @@ static int f2fs_setup_casefold(struct f2fs_sb_info *sbi)
 
 		sbi->sb->s_encoding = encoding;
 		sbi->sb->s_encoding_flags = encoding_flags;
-		sbi->sb->s_d_op = &f2fs_dentry_ops;
 	}
 #else
 	if (f2fs_sb_has_casefold(sbi)) {
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index ef85ec167a843..dc3af703db30d 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -209,6 +209,7 @@ static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
 	dbg_gen("'%pd' in dir ino %lu", dentry, dir->i_ino);
 
 	err = fscrypt_prepare_lookup(dir, dentry, &nm);
+	generic_set_encrypted_ci_d_ops(dir, dentry);
 	if (err == -ENOENT)
 		return d_splice_alias(NULL, dentry);
 	if (err)
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index b199b6e976ce3..f99e402abb540 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -596,8 +596,9 @@ static inline int fscrypt_prepare_rename(struct inode *old_dir,
  * filenames are presented in encrypted form.  Therefore, we'll try to set up
  * the directory's encryption key, but even without it the lookup can continue.
  *
- * This also installs a custom ->d_revalidate() method which will invalidate the
- * dentry if it was created without the key and the key is later added.
+ * After calling this function, a filesystem should ensure that its dentry
+ * operations contain fscrypt_d_revalidate if DCACHE_ENCRYPTED_NAME was set,
+ * so that the dentry can be invalidated if the key is later added.
  *
  * Return: 0 on success; -ENOENT if key is unavailable but the filename isn't a
  * correctly formed encoded ciphertext name, so a negative dentry should be
-- 
2.25.1.481.gfbce0eb801-goog

[PATCH v8 8/8] f2fs: Handle casefolding with Encryption

[Daniel Rosenberg]

This expands f2fs's casefolding support to include encrypted
directories. For encrypted directories, we use the siphash of the
casefolded name. This ensures there is no direct way to go from an
unencrypted name to the stored hash on disk without knowledge of the
encryption policy keys.

Additionally, we switch to using the vfs layer's casefolding support
instead of storing this information inside of f2fs's private data.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/f2fs/dir.c    | 65 +++++++++++++++++++++++++++++++-----------------
 fs/f2fs/f2fs.h   | 11 +++-----
 fs/f2fs/hash.c   | 25 +++++++++++++------
 fs/f2fs/inline.c |  9 ++++---
 fs/f2fs/super.c  |  6 -----
 5 files changed, 67 insertions(+), 49 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 38c0e6d589be4..a2a21b651c8b3 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -108,34 +108,52 @@ static struct f2fs_dir_entry *find_in_block(struct inode *dir,
  * Test whether a case-insensitive directory entry matches the filename
  * being searched for.
  *
+ * Only called for encrypted names if the key is available.
+ *
  * Returns: 0 if the directory entry matches, more than 0 if it
  * doesn't match or less than zero on error.
  */
-int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,
-				const struct qstr *entry, bool quick)
+static int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,
+			   u8 *de_name, size_t de_name_len, bool quick)
 {
 	const struct super_block *sb = parent->i_sb;
 	const struct unicode_map *um = sb->s_encoding;
+	struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
+	struct qstr entry = QSTR_INIT(de_name, de_name_len);
 	int ret;
 
+	if (IS_ENCRYPTED(parent)) {
+		const struct fscrypt_str encrypted_name =
+				FSTR_INIT(de_name, de_name_len);
+
+		decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
+		if (!decrypted_name.name)
+			return -ENOMEM;
+		ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
+						&decrypted_name);
+		if (ret < 0)
+			goto out;
+		entry.name = decrypted_name.name;
+		entry.len = decrypted_name.len;
+	}
+
 	if (quick)
-		ret = utf8_strncasecmp_folded(um, name, entry);
+		ret = utf8_strncasecmp_folded(um, name, &entry);
 	else
-		ret = utf8_strncasecmp(um, name, entry);
-
+		ret = utf8_strncasecmp(um, name, &entry);
 	if (ret < 0) {
 		/* Handle invalid character sequence as either an error
 		 * or as an opaque byte sequence.
 		 */
 		if (sb_has_enc_strict_mode(sb))
-			return -EINVAL;
-
-		if (name->len != entry->len)
-			return 1;
-
-		return !!memcmp(name->name, entry->name, name->len);
+			ret = -EINVAL;
+		else if (name->len != entry.len)
+			ret = 1;
+		else
+			ret = !!memcmp(name->name, entry.name, entry.len);
 	}
-
+out:
+	kfree(decrypted_name.name);
 	return ret;
 }
 
@@ -173,24 +191,24 @@ static inline bool f2fs_match_name(struct f2fs_dentry_ptr *d,
 {
 #ifdef CONFIG_UNICODE
 	struct inode *parent = d->inode;
-	struct super_block *sb = parent->i_sb;
-	struct qstr entry;
+	u8 *name;
+	int len;
 #endif
 
 	if (de->hash_code != namehash)
 		return false;
 
 #ifdef CONFIG_UNICODE
-	entry.name = d->filename[bit_pos];
-	entry.len = de->name_len;
+	name = d->filename[bit_pos];
+	len = le16_to_cpu(de->name_len);
 
-	if (sb->s_encoding && IS_CASEFOLDED(parent)) {
+	if (needs_casefold(parent)) {
 		if (cf_str->name) {
 			struct qstr cf = {.name = cf_str->name,
 					  .len = cf_str->len};
-			return !f2fs_ci_compare(parent, &cf, &entry, true);
+			return !f2fs_ci_compare(parent, &cf, name, len, true);
 		}
-		return !f2fs_ci_compare(parent, fname->usr_fname, &entry,
+		return !f2fs_ci_compare(parent, fname->usr_fname, name, len,
 					false);
 	}
 #endif
@@ -616,13 +634,13 @@ void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
 
 int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
 				const struct qstr *orig_name,
+				f2fs_hash_t dentry_hash,
 				struct inode *inode, nid_t ino, umode_t mode)
 {
 	unsigned int bit_pos;
 	unsigned int level;
 	unsigned int current_depth;
 	unsigned long bidx, block;
-	f2fs_hash_t dentry_hash;
 	unsigned int nbucket, nblock;
 	struct page *dentry_page = NULL;
 	struct f2fs_dentry_block *dentry_blk = NULL;
@@ -632,7 +650,6 @@ int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
 
 	level = 0;
 	slots = GET_DENTRY_SLOTS(new_name->len);
-	dentry_hash = f2fs_dentry_hash(dir, new_name, NULL);
 
 	current_depth = F2FS_I(dir)->i_current_depth;
 	if (F2FS_I(dir)->chash == dentry_hash) {
@@ -718,17 +735,19 @@ int f2fs_add_dentry(struct inode *dir, struct fscrypt_name *fname,
 				struct inode *inode, nid_t ino, umode_t mode)
 {
 	struct qstr new_name;
+	f2fs_hash_t dentry_hash;
 	int err = -EAGAIN;
 
 	new_name.name = fname_name(fname);
 	new_name.len = fname_len(fname);
 
 	if (f2fs_has_inline_dentry(dir))
-		err = f2fs_add_inline_entry(dir, &new_name, fname->usr_fname,
+		err = f2fs_add_inline_entry(dir, &new_name, fname,
 							inode, ino, mode);
+	dentry_hash = f2fs_dentry_hash(dir, &new_name, fname);
 	if (err == -EAGAIN)
 		err = f2fs_add_regular_entry(dir, &new_name, fname->usr_fname,
-							inode, ino, mode);
+						dentry_hash, inode, ino, mode);
 
 	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
 	return err;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 0fc153b5a5c09..0937befccc578 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3073,11 +3073,6 @@ int f2fs_update_extension_list(struct f2fs_sb_info *sbi, const char *name,
 							bool hot, bool set);
 struct dentry *f2fs_get_parent(struct dentry *child);
 
-extern int f2fs_ci_compare(const struct inode *parent,
-			   const struct qstr *name,
-			   const struct qstr *entry,
-			   bool quick);
-
 /*
  * dir.c
  */
@@ -3111,7 +3106,7 @@ void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
 			const struct qstr *name, f2fs_hash_t name_hash,
 			unsigned int bit_pos);
 int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
-			const struct qstr *orig_name,
+			const struct qstr *orig_name, f2fs_hash_t dentry_hash,
 			struct inode *inode, nid_t ino, umode_t mode);
 int f2fs_add_dentry(struct inode *dir, struct fscrypt_name *fname,
 			struct inode *inode, nid_t ino, umode_t mode);
@@ -3144,7 +3139,7 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi);
  * hash.c
  */
 f2fs_hash_t f2fs_dentry_hash(const struct inode *dir,
-		const struct qstr *name_info, struct fscrypt_name *fname);
+		const struct qstr *name_info, const struct fscrypt_name *fname);
 
 /*
  * node.c
@@ -3656,7 +3651,7 @@ struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir,
 int f2fs_make_empty_inline_dir(struct inode *inode, struct inode *parent,
 			struct page *ipage);
 int f2fs_add_inline_entry(struct inode *dir, const struct qstr *new_name,
-			const struct qstr *orig_name,
+			const struct fscrypt_name *fname,
 			struct inode *inode, nid_t ino, umode_t mode);
 void f2fs_delete_inline_entry(struct f2fs_dir_entry *dentry,
 				struct page *page, struct inode *dir,
diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
index 28acb24e7a7a8..23df352b969a1 100644
--- a/fs/f2fs/hash.c
+++ b/fs/f2fs/hash.c
@@ -68,8 +68,9 @@ static void str2hashbuf(const unsigned char *msg, size_t len,
 		*buf++ = pad;
 }
 
-static f2fs_hash_t __f2fs_dentry_hash(const struct qstr *name_info,
-				struct fscrypt_name *fname)
+static f2fs_hash_t __f2fs_dentry_hash(const struct inode *dir,
+				const struct qstr *name_info,
+				const struct fscrypt_name *fname)
 {
 	__u32 hash;
 	f2fs_hash_t f2fs_hash;
@@ -79,12 +80,17 @@ static f2fs_hash_t __f2fs_dentry_hash(const struct qstr *name_info,
 	size_t len = name_info->len;
 
 	/* encrypted bigname case */
-	if (fname && !fname->disk_name.name)
+	if (fname && !fname->is_ciphertext_name)
 		return cpu_to_le32(fname->hash);
 
 	if (is_dot_dotdot(name_info))
 		return 0;
 
+	if (IS_CASEFOLDED(dir) && IS_ENCRYPTED(dir)) {
+		f2fs_hash = cpu_to_le32(fscrypt_fname_siphash(dir, name_info));
+		return f2fs_hash;
+	}
+
 	/* Initialize the default seed for the hash checksum functions */
 	buf[0] = 0x67452301;
 	buf[1] = 0xefcdab89;
@@ -106,7 +112,7 @@ static f2fs_hash_t __f2fs_dentry_hash(const struct qstr *name_info,
 }
 
 f2fs_hash_t f2fs_dentry_hash(const struct inode *dir,
-		const struct qstr *name_info, struct fscrypt_name *fname)
+		const struct qstr *name_info, const struct fscrypt_name *fname)
 {
 #ifdef CONFIG_UNICODE
 	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
@@ -114,27 +120,30 @@ f2fs_hash_t f2fs_dentry_hash(const struct inode *dir,
 	int r, dlen;
 	unsigned char *buff;
 	struct qstr folded;
+	const struct qstr *name = fname ? fname->usr_fname : name_info;
 
 	if (!name_info->len || !IS_CASEFOLDED(dir))
 		goto opaque_seq;
 
+	if (IS_ENCRYPTED(dir) && !fscrypt_has_encryption_key(dir))
+		goto opaque_seq;
+
 	buff = f2fs_kzalloc(sbi, sizeof(char) * PATH_MAX, GFP_KERNEL);
 	if (!buff)
 		return -ENOMEM;
-
-	dlen = utf8_casefold(um, name_info, buff, PATH_MAX);
+	dlen = utf8_casefold(um, name, buff, PATH_MAX);
 	if (dlen < 0) {
 		kvfree(buff);
 		goto opaque_seq;
 	}
 	folded.name = buff;
 	folded.len = dlen;
-	r = __f2fs_dentry_hash(&folded, fname);
+	r = __f2fs_dentry_hash(dir, &folded, fname);
 
 	kvfree(buff);
 	return r;
 
 opaque_seq:
 #endif
-	return __f2fs_dentry_hash(name_info, fname);
+	return __f2fs_dentry_hash(dir, name_info, fname);
 }
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 4167e54081518..4b8fc643df735 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -465,8 +465,8 @@ static int f2fs_add_inline_entries(struct inode *dir, void *inline_dentry)
 		ino = le32_to_cpu(de->ino);
 		fake_mode = f2fs_get_de_type(de) << S_SHIFT;
 
-		err = f2fs_add_regular_entry(dir, &new_name, NULL, NULL,
-							ino, fake_mode);
+		err = f2fs_add_regular_entry(dir, &new_name, NULL,
+					de->hash_code, NULL, ino, fake_mode);
 		if (err)
 			goto punch_dentry_pages;
 
@@ -578,7 +578,7 @@ int f2fs_try_convert_inline_dir(struct inode *dir, struct dentry *dentry)
 }
 
 int f2fs_add_inline_entry(struct inode *dir, const struct qstr *new_name,
-				const struct qstr *orig_name,
+				const struct fscrypt_name *fname,
 				struct inode *inode, nid_t ino, umode_t mode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
@@ -589,6 +589,7 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *new_name,
 	struct f2fs_dentry_ptr d;
 	int slots = GET_DENTRY_SLOTS(new_name->len);
 	struct page *page = NULL;
+	const struct qstr *orig_name = fname->usr_fname;
 	int err = 0;
 
 	ipage = f2fs_get_node_page(sbi, dir->i_ino);
@@ -619,7 +620,7 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *new_name,
 
 	f2fs_wait_on_page_writeback(ipage, NODE, true, true);
 
-	name_hash = f2fs_dentry_hash(dir, new_name, NULL);
+	name_hash = f2fs_dentry_hash(dir, new_name, fname);
 	f2fs_update_dentry(ino, mode, &d, new_name, name_hash, bit_pos);
 
 	set_page_dirty(ipage);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 7520a9c04c75e..b30925a44ac71 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3228,12 +3228,6 @@ static int f2fs_setup_casefold(struct f2fs_sb_info *sbi)
 		struct unicode_map *encoding;
 		__u16 encoding_flags;
 
-		if (f2fs_sb_has_encrypt(sbi)) {
-			f2fs_err(sbi,
-				"Can't mount with encoding and encryption");
-			return -EINVAL;
-		}
-
 		if (f2fs_sb_read_encoding(sbi->raw_super, &encoding_info,
 					  &encoding_flags)) {
 			f2fs_err(sbi,
-- 
2.25.1.481.gfbce0eb801-goog

Re: [PATCH v8 2/8] fs: Add standard casefolding support

[Al Viro]

On Fri, Mar 06, 2020 at 06:36:05PM -0800, Daniel Rosenberg wrote:

> +/**
> + * generic_ci_d_hash - generic implementation of d_hash for casefolding
> + * @dentry: Entry whose name we are hashing
> + * @len: length of str
> + * @qstr: name of the dentry, safely paired with len
> + * @str: qstr to set hash of
> + *
> + * This performs a case insensitive hash of the given str.
> + * If casefolding is not required, it leaves the hash unchanged.
> + */
> +int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str)
> +{
> +	const struct inode *inode = READ_ONCE(dentry->d_inode);
> +	struct super_block *sb = dentry->d_sb;
> +	const struct unicode_map *um = sb->s_encoding;
> +	char small_name[DNAME_INLINE_LEN];
> +	struct qstr entry = QSTR_INIT(str->name, str->len);
> +	int ret = 0;
> +
> +	if (!inode || !needs_casefold(inode))
> +		return 0;
> +
> +	if (make_name_stable(um, dentry, &entry, small_name))
> +		goto err;
> +	ret = utf8_casefold_hash(um, dentry, &entry);
> +	if (ret < 0)
> +		goto err;
> +
> +	return 0;
> +err:
> +	if (sb_has_enc_strict_mode(sb))
> +		ret = -EINVAL;
> +	else
> +		ret = 0;
> +	return ret;
> +}

	Have you even tested that?  Could you tell me where does the calculated
hash go?  And just what is it doing trying to check if the name we are about to
look up in directory specified by 'dentry' might be pointing to dentry->d_iname?

Re: [PATCH v8 0/8] Support for Casefolding and Encryption

[Eric Biggers]

On Fri, Mar 06, 2020 at 06:36:03PM -0800, Daniel Rosenberg wrote:
> These patches are all on top of torvalds/master
> 
> Ext4 and F2FS currently both support casefolding and encryption, but not at
> the same time. These patches aim to rectify that.
> 
> I've left off the Ext4 patches that enable casefolding and ecryption from
> this revision since they still need some fixups, and I haven't gotten around
> to the fsck changes yet.
> 
> I moved the identical casefolding dcache operations for ext4 and f2fs into
> fs/libfs.c, as all filesystems using casefolded names will want them.
> 
> I've also adjust fscrypt to not set it's d_revalidate operation during it's
> prepare lookup, instead having the calling filesystem set it up. This is
> done to that the filesystem may have it's own dentry_operations. Also added
> a helper function in libfs.c that will work for filesystems supporting both
> casefolding and fscrypt.
> 
> For Ext4, since the hash for encrypted casefolded directory names cannot be
> computed without the key, we need to store the hash on disk. We only do so
> for encrypted and casefolded directories to avoid on disk format changes.
> Previously encryption and casefolding could not be on the same filesystem,
> and we're relaxing that requirement. F2fs is a bit more straightforward
> since it already stores hashes on disk.
> 
> I've updated the related tools with just enough to enable the feature. I
> still need to adjust ext4's fsck's, although without access to the keys,
> neither fsck will be able to verify the hashes of casefolded and encrypted
> names.
> 

Can you please do some more testing?  Just playing around with casefolding (not
even encryption yet), it didn't take long to notice some problems.  E.g.

$ mkfs.f2fs -f -C utf8 /dev/vdc
$ mount /vdc
$ mkdir /vdc/dir
$ chattr +F /vdc/dir
$ echo foo > /vdc/dir/a
$ cat /vdc/dir/A
foo
$ rm /vdc/dir/a
$ cat /vdc/dir/A
foo

I.e. 'rm' only deleted "a", not "A", even though they're the same file.

Also, there's a casefolding test in xfstests, and with this patchset applied it
fails and causes kernel warnings.  It passes without this patchset applied.

$ kvm-xfstests -c f2fs -g casefold

[...]
[    5.947961] ------------[ cut here ]------------
[    5.948714] WARNING: CPU: 1 PID: 1053 at fs/inode.c:302 drop_nlink+0x1e/0x30
[    5.949742] CPU: 1 PID: 1053 Comm: rm Not tainted 5.6.0-rc4-00008-gf9c20981ece1 #4
[    5.950835] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20191223_100556-anatol 04/01/2014
[    5.952234] RIP: 0010:drop_nlink+0x1e/0x30
[    5.952838] Code: 44 24 10 eb da 0f 0b 0f 1f 44 00 00 8b 47 40 8d 50 ff 85 c0 74 14 85 d2 89 57 40 75 0c 48 8b 47 28 f0 48 ff 80 98 5
[    5.955509] RSP: 0018:ffffc90001633d60 EFLAGS: 00010246
[    5.956273] RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000000000
[    5.957303] RDX: 00000000ffffffff RSI: 0000000000000001 RDI: ffff88807a84d688
[    5.958332] RBP: ffffc90001633d90 R08: 0000000000000000 R09: 0000000000000000
[    5.959363] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88807a84d688
[    5.960392] R13: ffff88807cf97648 R14: ffff88807a84da50 R15: ffff8880776bc000
[    5.961424] FS:  00007f7003d12540(0000) GS:ffff88807fd00000(0000) knlGS:0000000000000000
[    5.962588] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    5.963422] CR2: 000055a037bf5448 CR3: 00000000780ad000 CR4: 00000000003406e0
[    5.964453] Call Trace:
[    5.964828]  ? f2fs_drop_nlink+0x56/0x140
[    5.965417]  f2fs_delete_inline_entry+0x19e/0x1e0
[    5.966106]  f2fs_delete_entry+0x1be/0x320
[    5.966705]  f2fs_unlink+0x10c/0x360
[    5.967239]  vfs_unlink+0xf1/0x1d0
[    5.967747]  do_unlinkat+0x188/0x2c0
[    5.968254]  __x64_sys_unlinkat+0x33/0x50
[    5.968709]  do_syscall_64+0x4a/0x1f0
[    5.969130]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[    5.969533] RIP: 0033:0x7f7003c3bff7
[    5.969804] Code: 73 01 c3 48 8b 0d 99 ee 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 07 01 8
[    5.971154] RSP: 002b:00007ffde2c23588 EFLAGS: 00000206 ORIG_RAX: 0000000000000107
[    5.971707] RAX: ffffffffffffffda RBX: 000055a037bf5570 RCX: 00007f7003c3bff7
[    5.972242] RDX: 0000000000000000 RSI: 000055a037bf4340 RDI: 00000000ffffff9c
[    5.972774] RBP: 000055a037bf42b0 R08: 0000000000000003 R09: 0000000000000000
[    5.973305] R10: fffffffffffffbd8 R11: 0000000000000206 R12: 00007ffde2c23770
[    5.973837] R13: 0000000000000000 R14: 000055a037bf5570 R15: 0000000000000000
[    5.974367] irq event stamp: 1134
[    5.974621] hardirqs last  enabled at (1133): [<ffffffff810f6645>] ktime_get_coarse_real_ts64+0x95/0xb0
[    5.975321] hardirqs last disabled at (1134): [<ffffffff81001b79>] trace_hardirqs_off_thunk+0x1a/0x1c
[    5.976003] softirqs last  enabled at (502): [<ffffffff8102ab53>] fpu__clear+0xb3/0x1b0
[    5.976586] softirqs last disabled at (500): [<ffffffff8102ab15>] fpu__clear+0x75/0x1b0
[    5.977181] ---[ end trace 31b6c5defdf04f01 ]---
[    5.989770] ------------[ cut here ]------------
[...]
[failed, exit status 1] [21:03:50]- output mismatch (see /results/f2fs/results-default/generic/556.out.bad)
    --- tests/generic/556.out	2020-02-18 11:22:36.000000000 -0800
    +++ /results/f2fs/results-default/generic/556.out.bad	2020-03-06 21:03:50.783730049 -0800
    @@ -12,5 +12,5 @@
     # file: SCRATCH_MNT/xattrs/x/f1
     user.foo="bar"
     
    -touch: setting times of 'SCRATCH_MNT/strict/corac'$'\314\247\303': Invalid argument
    -touch: setting times of 'SCRATCH_MNT/strict/cora'$'\303\247\303': Invalid argument
    +_check_generic_filesystem: filesystem on /dev/vdc is inconsistent
    +(see /results/f2fs/results-default/generic/556.full for details)
    ...
    (Run 'diff -u /root/xfstests/tests/generic/556.out /results/f2fs/results-default/generic/556.out.bad'  to see the entire diff)
Ran: generic/556
Failures: generic/556
Failed 1 of 1 tests

Re: [PATCH v8 8/8] f2fs: Handle casefolding with Encryption

[Eric Biggers]

On Fri, Mar 06, 2020 at 06:36:11PM -0800, Daniel Rosenberg wrote:
>  int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
>  				const struct qstr *orig_name,
> +				f2fs_hash_t dentry_hash,
>  				struct inode *inode, nid_t ino, umode_t mode)
>  {
>  	unsigned int bit_pos;
>  	unsigned int level;
>  	unsigned int current_depth;
>  	unsigned long bidx, block;
> -	f2fs_hash_t dentry_hash;
>  	unsigned int nbucket, nblock;
>  	struct page *dentry_page = NULL;
>  	struct f2fs_dentry_block *dentry_blk = NULL;
> @@ -632,7 +650,6 @@ int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
>  
>  	level = 0;
>  	slots = GET_DENTRY_SLOTS(new_name->len);
> -	dentry_hash = f2fs_dentry_hash(dir, new_name, NULL);
>  
>  	current_depth = F2FS_I(dir)->i_current_depth;
>  	if (F2FS_I(dir)->chash == dentry_hash) {
> @@ -718,17 +735,19 @@ int f2fs_add_dentry(struct inode *dir, struct fscrypt_name *fname,
>  				struct inode *inode, nid_t ino, umode_t mode)
>  {
>  	struct qstr new_name;
> +	f2fs_hash_t dentry_hash;
>  	int err = -EAGAIN;
>  
>  	new_name.name = fname_name(fname);
>  	new_name.len = fname_len(fname);
>  
>  	if (f2fs_has_inline_dentry(dir))
> -		err = f2fs_add_inline_entry(dir, &new_name, fname->usr_fname,
> +		err = f2fs_add_inline_entry(dir, &new_name, fname,
>  							inode, ino, mode);
> +	dentry_hash = f2fs_dentry_hash(dir, &new_name, fname);
>  	if (err == -EAGAIN)
>  		err = f2fs_add_regular_entry(dir, &new_name, fname->usr_fname,
> -							inode, ino, mode);
> +						dentry_hash, inode, ino, mode);
>  

Why are the changes to f2fs_add_dentry(), f2fs_add_regular_entry(), and
f2fs_add_inline_entry() being made?  Directories can't be modified through
no-key names, so there's no need to make this part of the code handle grabbing
the dentry hash from the struct fscrypt_name.  And both the on-disk and original
filenames were already passed to these functions.  So what else do we need?

> +static f2fs_hash_t __f2fs_dentry_hash(const struct inode *dir,
> +				const struct qstr *name_info,
> +				const struct fscrypt_name *fname)
>  {
>  	__u32 hash;
>  	f2fs_hash_t f2fs_hash;
> @@ -79,12 +80,17 @@ static f2fs_hash_t __f2fs_dentry_hash(const struct qstr *name_info,
>  	size_t len = name_info->len;
>  
>  	/* encrypted bigname case */
> -	if (fname && !fname->disk_name.name)
> +	if (fname && !fname->is_ciphertext_name)
>  		return cpu_to_le32(fname->hash);

Isn't this check backwards?  The hash is valid if fname->is_ciphertext_name, not
if !fname->is_ciphertext_name.

(Maybe the phrase "ciphertext name" is causing confusion, as we're now calling
them "no-key names" instead?  We could rename it, if that would help.)

- Eric

Re: [PATCH v8 6/8] libfs: Add generic function for setting dentry_ops

[Eric Biggers]

On Fri, Mar 06, 2020 at 06:36:09PM -0800, Daniel Rosenberg wrote:
> This adds a function to set dentry operations at lookup time that will
> work for both encrypted files and casefolded filenames.
> 
> A filesystem that supports both features simultaneously can use this
> function during lookup preperations to set up its dentry operations once
> fscrypt no longer does that itself.
> 
> Signed-off-by: Daniel Rosenberg <drosen@google.com>
> ---
>  fs/libfs.c         | 50 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/fs.h |  2 ++
>  2 files changed, 52 insertions(+)
> 
> diff --git a/fs/libfs.c b/fs/libfs.c
> index 0eaa63a9ae037..bdda03c8ece9e 100644
> --- a/fs/libfs.c
> +++ b/fs/libfs.c
> @@ -1474,4 +1474,54 @@ int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str)
>  	return ret;
>  }
>  EXPORT_SYMBOL(generic_ci_d_hash);
> +
> +static const struct dentry_operations generic_ci_dentry_ops = {
> +	.d_hash = generic_ci_d_hash,
> +	.d_compare = generic_ci_d_compare,
> +};
> +#endif
> +
> +#ifdef CONFIG_FS_ENCRYPTION
> +static const struct dentry_operations generic_encrypted_dentry_ops = {
> +	.d_revalidate = fscrypt_d_revalidate,
> +};
> +#endif
> +
> +#if IS_ENABLED(CONFIG_UNICODE) && IS_ENABLED(CONFIG_FS_ENCRYPTION)
> +static const struct dentry_operations generic_encrypted_ci_dentry_ops = {
> +	.d_hash = generic_ci_d_hash,
> +	.d_compare = generic_ci_d_compare,
> +	.d_revalidate = fscrypt_d_revalidate,
> +};
> +#endif
> +
> +/**
> + * generic_set_encrypted_ci_d_ops - helper for setting d_ops for given dentry
> + * @dir:	parent of dentry whose ops to set
> + * @dentry:	dentry to set ops on
> + *
> + * This function sets the dentry ops for the given dentry to handle both
> + * casefolding and encryption of the dentry name.
> + */
> +void generic_set_encrypted_ci_d_ops(struct inode *dir, struct dentry *dentry)
> +{
> +#ifdef CONFIG_FS_ENCRYPTION
> +	if (dentry->d_flags & DCACHE_ENCRYPTED_NAME) {
> +#ifdef CONFIG_UNICODE
> +		if (dir->i_sb->s_encoding) {
> +			d_set_d_op(dentry, &generic_encrypted_ci_dentry_ops);
> +			return;
> +		}
>  #endif
> +		d_set_d_op(dentry, &generic_encrypted_dentry_ops);
> +		return;
> +	}
> +#endif
> +#ifdef CONFIG_UNICODE
> +	if (dir->i_sb->s_encoding) {
> +		d_set_d_op(dentry, &generic_ci_dentry_ops);
> +		return;
> +	}
> +#endif
> +}
> +EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops);

What's wrong with using dentry->d_sb?  Then the 'dir' parameter wouldn't be
needed.

Also, can you please document why the dentry_operations for casefolding are set
per-filesystem while the dentry_operations for encryption are set per-dentry,
despite both features actually being per-directory things?

- Eric

Re: [PATCH v8 2/8] fs: Add standard casefolding support

[Daniel Rosenberg]

On Fri, Mar 6, 2020 at 7:48 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> On Fri, Mar 06, 2020 at 06:36:05PM -0800, Daniel Rosenberg wrote:
>
>         Have you even tested that?  Could you tell me where does the calculated
> hash go?  And just what is it doing trying to check if the name we are about to
> look up in directory specified by 'dentry' might be pointing to dentry->d_iname?

Turns out I tested exactly not that :/ Ran tests on the wrong kernel.
I've fixed my setup so that shouldn't happen again. The calculated
hash there goes exactly nowhere because I failed to copy it back into
the original qstr.
I'm trying to see if the name is a small name, which, if my
understanding is correct, is the only time a name might change from
underneath you in an RCU context. This assumes that the name either
comes from the dentry, or is otherwise not subject to changes. It's
based around the check that take_dentry_name_snapshot does. It does
feel a bit sketchy to assume that, so I'm very open to other
suggestions there.

I'm going through that hassle because the various utf8 functions do a
lot of dereferencing the string and manipulating pointers by those
values, expecting them to be consistent. It might be enough to just go
through that code and add a bunch of checks to make sure we can't
accidentally walk off of either end.