From 4dbe8e4413d70ac4f163592d69eef74d7824783a Mon Sep 17 00:00:00 2001

From: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Date: Mon, 4 Oct 2021 18:59:55 +0300

Subject: [Backport 4dbe8e4413d7] src: Refactor ntfs_readlink_hlp

Rename some variables.

Returned err by default is EINVAL.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

---

 src/inode.c | 91 +++++++++++++++++++++++-------------------------

 1 file changed, 43 insertions(+), 48 deletions(-)

diff --git a/src/inode.c b/src/inode.c

index 7dd162f6a7e26435b16c08b5efed6e283b975f54..d618b0573533c043acd2fadc59a20e9ce0c772cb 100644

--- a/src/inode.c

+++ b/src/inode.c

@@ -1763,15 +1763,15 @@ void ntfs_evict_inode(struct inode *inode)

 static noinline int ntfs_readlink_hlp(struct inode *inode, char *buffer,

 				      int buflen)

 {

-	int i, err = 0;

+	int i, err = -EINVAL;

 	struct ntfs_inode *ni = ntfs_i(inode);

 	struct super_block *sb = inode->i_sb;

 	struct ntfs_sb_info *sbi = sb->s_fs_info;

-	u64 i_size = inode->i_size;

-	u16 nlen = 0;

+	u64 size;

+	u16 ulen = 0;

 	void *to_free = NULL;

 	struct REPARSE_DATA_BUFFER *rp;

-	struct le_str *uni;

+	const __le16 *uname;

 	struct ATTRIB *attr;

 	/* Reparse data present. Try to parse it. */

@@ -1780,68 +1780,64 @@ static noinline int ntfs_readlink_hlp(struct inode *inode, char *buffer,

 	*buffer = 0;

-	/* Read into temporal buffer. */

-	if (i_size > sbi->reparse.max_size || i_size <= sizeof(u32)) {

-		err = -EINVAL;

-		goto out;

-	}

-

 	attr = ni_find_attr(ni, NULL, NULL, ATTR_REPARSE, NULL, 0, NULL, NULL);

-	if (!attr) {

-		err = -EINVAL;

+	if (!attr)

 		goto out;

-	}

 	if (!attr->non_res) {

-		rp = resident_data_ex(attr, i_size);

-		if (!rp) {

-			err = -EINVAL;

+		rp = resident_data_ex(attr, sizeof(struct REPARSE_DATA_BUFFER));

+		if (!rp)

 			goto out;

-		}

+		size = le32_to_cpu(attr->res.data_size);

 	} else {

-		rp = kmalloc(i_size, GFP_NOFS);

+		size = le64_to_cpu(attr->nres.data_size);

+		rp = NULL;

+	}

+

+	if (size > sbi->reparse.max_size || size <= sizeof(u32))

+		goto out;

+

+	if (!rp) {

+		rp = kmalloc(size, GFP_NOFS);

 		if (!rp) {

 			err = -ENOMEM;

 			goto out;

 		}

 		to_free = rp;

-		err = ntfs_read_run_nb(sbi, &ni->file.run, 0, rp, i_size, NULL);

+		/* Read into temporal buffer. */

+		err = ntfs_read_run_nb(sbi, &ni->file.run, 0, rp, size, NULL);

 		if (err)

 			goto out;

 	}

-	err = -EINVAL;

-

 	/* Microsoft Tag. */

 	switch (rp->ReparseTag) {

 	case IO_REPARSE_TAG_MOUNT_POINT:

 		/* Mount points and junctions. */

 		/* Can we use 'Rp->MountPointReparseBuffer.PrintNameLength'? */

-		if (i_size <= offsetof(struct REPARSE_DATA_BUFFER,

-				       MountPointReparseBuffer.PathBuffer))

+		if (size <= offsetof(struct REPARSE_DATA_BUFFER,

+				     MountPointReparseBuffer.PathBuffer))

 			goto out;

-		uni = Add2Ptr(rp,

-			      offsetof(struct REPARSE_DATA_BUFFER,

-				       MountPointReparseBuffer.PathBuffer) +

-				      le16_to_cpu(rp->MountPointReparseBuffer

-							  .PrintNameOffset) -

-				      2);

-		nlen = le16_to_cpu(rp->MountPointReparseBuffer.PrintNameLength);

+		uname = Add2Ptr(rp,

+				offsetof(struct REPARSE_DATA_BUFFER,

+					 MountPointReparseBuffer.PathBuffer) +

+					le16_to_cpu(rp->MountPointReparseBuffer

+							    .PrintNameOffset));

+		ulen = le16_to_cpu(rp->MountPointReparseBuffer.PrintNameLength);

 		break;

 	case IO_REPARSE_TAG_SYMLINK:

 		/* FolderSymbolicLink */

 		/* Can we use 'Rp->SymbolicLinkReparseBuffer.PrintNameLength'? */

-		if (i_size <= offsetof(struct REPARSE_DATA_BUFFER,

-				       SymbolicLinkReparseBuffer.PathBuffer))

+		if (size <= offsetof(struct REPARSE_DATA_BUFFER,

+				     SymbolicLinkReparseBuffer.PathBuffer))

 			goto out;

-		uni = Add2Ptr(rp,

-			      offsetof(struct REPARSE_DATA_BUFFER,

-				       SymbolicLinkReparseBuffer.PathBuffer) +

-				      le16_to_cpu(rp->SymbolicLinkReparseBuffer

-							  .PrintNameOffset) -

-				      2);

-		nlen = le16_to_cpu(

+		uname = Add2Ptr(

+			rp, offsetof(struct REPARSE_DATA_BUFFER,

+				     SymbolicLinkReparseBuffer.PathBuffer) +

+				    le16_to_cpu(rp->SymbolicLinkReparseBuffer

+							.PrintNameOffset));

+		ulen = le16_to_cpu(

 			rp->SymbolicLinkReparseBuffer.PrintNameLength);

 		break;

@@ -1873,29 +1869,28 @@ static noinline int ntfs_readlink_hlp(struct inode *inode, char *buffer,

 			goto out;

 		}

 		if (!IsReparseTagNameSurrogate(rp->ReparseTag) ||

-		    i_size <= sizeof(struct REPARSE_POINT)) {

+		    size <= sizeof(struct REPARSE_POINT)) {

 			goto out;

 		}

 		/* Users tag. */

-		uni = Add2Ptr(rp, sizeof(struct REPARSE_POINT) - 2);

-		nlen = le16_to_cpu(rp->ReparseDataLength) -

+		uname = Add2Ptr(rp, sizeof(struct REPARSE_POINT));

+		ulen = le16_to_cpu(rp->ReparseDataLength) -

 		       sizeof(struct REPARSE_POINT);

 	}

 	/* Convert nlen from bytes to UNICODE chars. */

-	nlen >>= 1;

+	ulen >>= 1;

 	/* Check that name is available. */

-	if (!nlen || &uni->name[nlen] > (__le16 *)Add2Ptr(rp, i_size))

+	if (!ulen || uname + ulen > (__le16 *)Add2Ptr(rp, size))

 		goto out;

 	/* If name is already zero terminated then truncate it now. */

-	if (!uni->name[nlen - 1])

-		nlen -= 1;

-	uni->len = nlen;

+	if (!uname[ulen - 1])

+		ulen -= 1;

-	err = ntfs_utf16_to_nls(sbi, uni, buffer, buflen);

+	err = ntfs_utf16_to_nls(sbi, uname, ulen, buffer, buflen);

 	if (err < 0)

 		goto out;

-- 

2.31.1