[PATCH] fs/ntfs3: preserve colons in symlink targets

[Hungyu Lin <dennylin0707@gmail.com>]

ntfs_nls_to_utf16() parses colon-delimited ADS names when the ads mount
option is enabled. ntfs_create_reparse_buffer() also uses it to convert
the complete symlink target, so "ln -s foo:bar link" succeeds but stores
"foo" as the target. Following a link to a named data stream can then
access the unnamed stream instead.

Add a parse_ads argument and disable parsing when converting symlink
targets. Keep parsing enabled for the other callers to preserve their
existing behavior.

Fixes: be310476e886 ("fs/ntfs3: Add basic support for alternative data streams")
Cc: stable@vger.kernel.org
Signed-off-by: Hungyu Lin <dennylin0707@gmail.com>
---
 fs/ntfs3/dir.c     |  5 +++--
 fs/ntfs3/fsntfs.c  |  2 +-
 fs/ntfs3/inode.c   |  2 +-
 fs/ntfs3/namei.c   | 10 +++++-----
 fs/ntfs3/ntfs_fs.h |  2 +-
 5 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/fs/ntfs3/dir.c b/fs/ntfs3/dir.c
index 14ca54e54578..be3c6a7fc57a 100644
--- a/fs/ntfs3/dir.c
+++ b/fs/ntfs3/dir.c
@@ -173,6 +173,7 @@ static int _utf8s_to_utf16s(const u8 *s, int inlen, enum utf16_endian endian,
  * @uni:	Destination memory.
  * @max_ulen:	Destination memory.
  * @endian:	Endian of target UTF-16 string.
+ * @parse_ads:	Whether to parse an ADS delimiter.
  *
  * This function is called:
  * - to create NTFS name
@@ -182,7 +183,7 @@ static int _utf8s_to_utf16s(const u8 *s, int inlen, enum utf16_endian endian,
  */
 int ntfs_nls_to_utf16(struct ntfs_sb_info *sbi, const u8 *name, u32 name_len,
 		      struct cpu_str *uni, u32 max_ulen,
-		      enum utf16_endian endian)
+		      enum utf16_endian endian, bool parse_ads)
 {
 	int ret, slen, i;
 	const u8 *end;
@@ -239,7 +240,7 @@ int ntfs_nls_to_utf16(struct ntfs_sb_info *sbi, const u8 *name, u32 name_len,
 
 	uni->len = ret;
 	uni->ads_len = 0;
-	if (ret > 0 && ads) {
+	if (ret > 0 && ads && parse_ads) {
 		uname = uni->name;
 		/* Find delimiter in range [1 : ret-2). */
 		for (i = 1; i + 1 < ret; i++) {
diff --git a/fs/ntfs3/fsntfs.c b/fs/ntfs3/fsntfs.c
index 97c04ab2763a..b06de8566a72 100644
--- a/fs/ntfs3/fsntfs.c
+++ b/fs/ntfs3/fsntfs.c
@@ -2668,7 +2668,7 @@ int ntfs_set_label(struct ntfs_sb_info *sbi, u8 *label, int len)
 		return -ENOMEM;
 
 	err = ntfs_nls_to_utf16(sbi, label, len, uni, (PATH_MAX - 2) / 2,
-				UTF16_LITTLE_ENDIAN);
+				UTF16_LITTLE_ENDIAN, true);
 	if (err < 0)
 		goto out;
 
diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 5a8d362155ac..d883c4b47e83 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -1315,7 +1315,7 @@ ntfs_create_reparse_buffer(struct ntfs_sb_info *sbi, const char *symname,
 	/* Convert link name to UTF-16. */
 	err = ntfs_nls_to_utf16(sbi, symname, size,
 				(struct cpu_str *)(rp_name - 1), 2 * size,
-				UTF16_LITTLE_ENDIAN);
+				UTF16_LITTLE_ENDIAN, false);
 	if (err < 0)
 		goto out;
 
diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c
index ae88cb66fb7e..ab9da0faa104 100644
--- a/fs/ntfs3/namei.c
+++ b/fs/ntfs3/namei.c
@@ -45,7 +45,7 @@ int fill_name_de(struct ntfs_sb_info *sbi, void *buf, const struct qstr *name,
 		/* Convert input string to unicode. */
 		err = ntfs_nls_to_utf16(sbi, name->name, name->len,
 					(struct cpu_str *)&fname->name_len,
-					NTFS_NAME_LEN, UTF16_LITTLE_ENDIAN);
+					NTFS_NAME_LEN, UTF16_LITTLE_ENDIAN, true);
 		if (err < 0)
 			return err;
 	}
@@ -82,7 +82,7 @@ static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *dentry,
 
 	err = ntfs_nls_to_utf16(ni->mi.sbi, dentry->d_name.name,
 				dentry->d_name.len, uni, NTFS_NAME_LEN,
-				UTF16_HOST_ENDIAN);
+				UTF16_HOST_ENDIAN, true);
 
 	if (err < 0) {
 		kfree(uni);
@@ -437,7 +437,7 @@ static int ntfs_d_hash(const struct dentry *dentry, struct qstr *name)
 	sbi = dentry->d_sb->s_fs_info;
 
 	err = ntfs_nls_to_utf16(sbi, name->name, name->len, uni, NTFS_NAME_LEN,
-				UTF16_HOST_ENDIAN);
+				UTF16_HOST_ENDIAN, true);
 	if (err < 0)
 		goto out;
 
@@ -496,7 +496,7 @@ static int ntfs_d_compare(const struct dentry *dentry, unsigned int len1,
 		return -ENOMEM;
 
 	ret = ntfs_nls_to_utf16(sbi, str, len1, uni1, NTFS_NAME_LEN,
-				UTF16_HOST_ENDIAN);
+				UTF16_HOST_ENDIAN, true);
 	if (ret < 0)
 		goto out;
 
@@ -509,7 +509,7 @@ static int ntfs_d_compare(const struct dentry *dentry, unsigned int len1,
 
 	ret = ntfs_nls_to_utf16(sbi, name->name, name->len,
 				(struct cpu_str *)uni2, NTFS_NAME_LEN,
-				UTF16_LITTLE_ENDIAN);
+				UTF16_LITTLE_ENDIAN, true);
 	if (ret < 0)
 		goto out;
 
diff --git a/fs/ntfs3/ntfs_fs.h b/fs/ntfs3/ntfs_fs.h
index 689151fcf993..5475eaeb49fe 100644
--- a/fs/ntfs3/ntfs_fs.h
+++ b/fs/ntfs3/ntfs_fs.h
@@ -540,7 +540,7 @@ int ntfs_utf16_to_nls(struct ntfs_sb_info *sbi, const __le16 *name, u32 len,
 		      u8 *buf, int buf_len);
 int ntfs_nls_to_utf16(struct ntfs_sb_info *sbi, const u8 *name, u32 name_len,
 		      struct cpu_str *uni, u32 max_ulen,
-		      enum utf16_endian endian);
+		      enum utf16_endian endian, bool parse_ads);
 struct inode *dir_search_flags(struct inode *dir, const struct cpu_str *uni,
 			       struct ntfs_fnd *fnd, u32 flags);
 static inline struct inode *dir_search(struct inode *dir,
-- 
2.43.0