[mirror_ubuntu-bionic-kernel.git] / fs / cifs / link.c

/*
 *   fs/cifs/link.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2008
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"

/*
 * M-F Symlink Functions - Begin
 */

#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
#define CIFS_MF_SYMLINK_FILE_SIZE \
	(CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)

#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
#define CIFS_MF_SYMLINK_MD5_FORMAT \
	"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
	md5_hash[0],  md5_hash[1],  md5_hash[2],  md5_hash[3], \
	md5_hash[4],  md5_hash[5],  md5_hash[6],  md5_hash[7], \
	md5_hash[8],  md5_hash[9],  md5_hash[10], md5_hash[11],\
	md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]

static int
symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
{
	int rc;
	unsigned int size;
	struct crypto_shash *md5;
	struct sdesc *sdescmd5;

	md5 = crypto_alloc_shash("md5", 0, 0);
	if (IS_ERR(md5)) {
		rc = PTR_ERR(md5);
		cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n",
			 __func__, rc);
		return rc;
	}
	size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
	sdescmd5 = kmalloc(size, GFP_KERNEL);
	if (!sdescmd5) {
		rc = -ENOMEM;
		goto symlink_hash_err;
	}
	sdescmd5->shash.tfm = md5;
	sdescmd5->shash.flags = 0x0;

	rc = crypto_shash_init(&sdescmd5->shash);
	if (rc) {
		cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
		goto symlink_hash_err;
	}
	rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
	if (rc) {
		cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
		goto symlink_hash_err;
	}
	rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
	if (rc)
		cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);

symlink_hash_err:
	crypto_free_shash(md5);
	kfree(sdescmd5);

	return rc;
}

static int
parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
		 char **_link_str)
{
	int rc;
	unsigned int link_len;
	const char *md5_str1;
	const char *link_str;
	u8 md5_hash[16];
	char md5_str2[34];

	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
		return -EINVAL;

	md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
	link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];

	rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
	if (rc != 1)
		return -EINVAL;

	rc = symlink_hash(link_len, link_str, md5_hash);
	if (rc) {
		cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
		return rc;
	}

	snprintf(md5_str2, sizeof(md5_str2),
		 CIFS_MF_SYMLINK_MD5_FORMAT,
		 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));

	if (strncmp(md5_str1, md5_str2, 17) != 0)
		return -EINVAL;

	if (_link_str) {
		*_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
		if (!*_link_str)
			return -ENOMEM;
	}

	*_link_len = link_len;
	return 0;
}

static int
format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
{
	int rc;
	unsigned int link_len;
	unsigned int ofs;
	u8 md5_hash[16];

	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
		return -EINVAL;

	link_len = strlen(link_str);

	if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
		return -ENAMETOOLONG;

	rc = symlink_hash(link_len, link_str, md5_hash);
	if (rc) {
		cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
		return rc;
	}

	snprintf(buf, buf_len,
		 CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
		 link_len,
		 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));

	ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
	memcpy(buf + ofs, link_str, link_len);

	ofs += link_len;
	if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
		buf[ofs] = '\n';
		ofs++;
	}

	while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
		buf[ofs] = ' ';
		ofs++;
	}

	return 0;
}

bool
couldbe_mf_symlink(const struct cifs_fattr *fattr)
{
	if (!S_ISREG(fattr->cf_mode))
		/* it's not a symlink */
		return false;

	if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
		/* it's not a symlink */
		return false;

	return true;
}

static int
create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
		  struct cifs_sb_info *cifs_sb, const char *fromName,
		  const char *toName)
{
	int rc;
	u8 *buf;
	unsigned int bytes_written = 0;

	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
	if (rc)
		goto out;

	if (tcon->ses->server->ops->create_mf_symlink)
		rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
					cifs_sb, fromName, buf, &bytes_written);
	else
		rc = -EOPNOTSUPP;

	if (rc)
		goto out;

	if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
		rc = -EIO;
out:
	kfree(buf);
	return rc;
}

static int
query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
		 struct cifs_sb_info *cifs_sb, const unsigned char *path,
		 char **symlinkinfo)
{
	int rc;
	u8 *buf = NULL;
	unsigned int link_len = 0;
	unsigned int bytes_read = 0;

	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	if (tcon->ses->server->ops->query_mf_symlink)
		rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
					      cifs_sb, path, buf, &bytes_read);
	else
		rc = -ENOSYS;

	if (rc)
		goto out;

	if (bytes_read == 0) { /* not a symlink */
		rc = -EINVAL;
		goto out;
	}

	rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
out:
	kfree(buf);
	return rc;
}

int
check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
		 struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
		 const unsigned char *path)
{
	int rc;
	u8 *buf = NULL;
	unsigned int link_len = 0;
	unsigned int bytes_read = 0;

	if (!couldbe_mf_symlink(fattr))
		/* it's not a symlink */
		return 0;

	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	if (tcon->ses->server->ops->query_mf_symlink)
		rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
					      cifs_sb, path, buf, &bytes_read);
	else
		rc = -ENOSYS;

	if (rc)
		goto out;

	if (bytes_read == 0) /* not a symlink */
		goto out;

	rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
	if (rc == -EINVAL) {
		/* it's not a symlink */
		rc = 0;
		goto out;
	}

	if (rc != 0)
		goto out;

	/* it is a symlink */
	fattr->cf_eof = link_len;
	fattr->cf_mode &= ~S_IFMT;
	fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
	fattr->cf_dtype = DT_LNK;
out:
	kfree(buf);
	return rc;
}

/*
 * SMB 1.0 Protocol specific functions
 */

int
cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
		      struct cifs_sb_info *cifs_sb, const unsigned char *path,
		      char *pbuf, unsigned int *pbytes_read)
{
	int rc;
	int oplock = 0;
	struct cifs_fid fid;
	struct cifs_open_parms oparms;
	struct cifs_io_parms io_parms;
	int buf_type = CIFS_NO_BUFFER;
	FILE_ALL_INFO file_info;

	oparms.tcon = tcon;
	oparms.cifs_sb = cifs_sb;
	oparms.desired_access = GENERIC_READ;
	oparms.create_options = CREATE_NOT_DIR;
	oparms.disposition = FILE_OPEN;
	oparms.path = path;
	oparms.fid = &fid;
	oparms.reconnect = false;

	rc = CIFS_open(xid, &oparms, &oplock, &file_info);
	if (rc)
		return rc;

	if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
		rc = -ENOENT;
		/* it's not a symlink */
		goto out;
	}

	io_parms.netfid = fid.netfid;
	io_parms.pid = current->tgid;
	io_parms.tcon = tcon;
	io_parms.offset = 0;
	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;

	rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
out:
	CIFSSMBClose(xid, tcon, fid.netfid);
	return rc;
}

int
cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
		       struct cifs_sb_info *cifs_sb, const unsigned char *path,
		       char *pbuf, unsigned int *pbytes_written)
{
	int rc;
	int oplock = 0;
	struct cifs_fid fid;
	struct cifs_open_parms oparms;
	struct cifs_io_parms io_parms;
	int create_options = CREATE_NOT_DIR;

	if (backup_cred(cifs_sb))
		create_options |= CREATE_OPEN_BACKUP_INTENT;

	oparms.tcon = tcon;
	oparms.cifs_sb = cifs_sb;
	oparms.desired_access = GENERIC_WRITE;
	oparms.create_options = create_options;
	oparms.disposition = FILE_CREATE;
	oparms.path = path;
	oparms.fid = &fid;
	oparms.reconnect = false;

	rc = CIFS_open(xid, &oparms, &oplock, NULL);
	if (rc)
		return rc;

	io_parms.netfid = fid.netfid;
	io_parms.pid = current->tgid;
	io_parms.tcon = tcon;
	io_parms.offset = 0;
	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;

	rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf, NULL, 0);
	CIFSSMBClose(xid, tcon, fid.netfid);
	return rc;
}

/*
 * M-F Symlink Functions - End
 */

int
cifs_hardlink(struct dentry *old_file, struct inode *inode,
	      struct dentry *direntry)
{
	int rc = -EACCES;
	unsigned int xid;
	char *from_name = NULL;
	char *to_name = NULL;
	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
	struct tcon_link *tlink;
	struct cifs_tcon *tcon;
	struct TCP_Server_Info *server;
	struct cifsInodeInfo *cifsInode;

	tlink = cifs_sb_tlink(cifs_sb);
	if (IS_ERR(tlink))
		return PTR_ERR(tlink);
	tcon = tlink_tcon(tlink);

	xid = get_xid();

	from_name = build_path_from_dentry(old_file);
	to_name = build_path_from_dentry(direntry);
	if ((from_name == NULL) || (to_name == NULL)) {
		rc = -ENOMEM;
		goto cifs_hl_exit;
	}

	if (tcon->unix_ext)
		rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
					    cifs_sb->local_nls,
					    cifs_sb->mnt_cifs_flags &
						CIFS_MOUNT_MAP_SPECIAL_CHR);
	else {
		server = tcon->ses->server;
		if (!server->ops->create_hardlink) {
			rc = -ENOSYS;
			goto cifs_hl_exit;
		}
		rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
						  cifs_sb);
		if ((rc == -EIO) || (rc == -EINVAL))
			rc = -EOPNOTSUPP;
	}

	d_drop(direntry);	/* force new lookup from server of target */

	/*
	 * if source file is cached (oplocked) revalidate will not go to server
	 * until the file is closed or oplock broken so update nlinks locally
	 */
	if (old_file->d_inode) {
		cifsInode = CIFS_I(old_file->d_inode);
		if (rc == 0) {
			spin_lock(&old_file->d_inode->i_lock);
			inc_nlink(old_file->d_inode);
			spin_unlock(&old_file->d_inode->i_lock);
			/*
			 * BB should we make this contingent on superblock flag
			 * NOATIME?
			 */
			/* old_file->d_inode->i_ctime = CURRENT_TIME; */
			/*
			 * parent dir timestamps will update from srv within a
			 * second, would it really be worth it to set the parent
			 * dir cifs inode time to zero to force revalidate
			 * (faster) for it too?
			 */
		}
		/*
		 * if not oplocked will force revalidate to get info on source
		 * file from srv
		 */
		cifsInode->time = 0;

		/*
		 * Will update parent dir timestamps from srv within a second.
		 * Would it really be worth it to set the parent dir (cifs
		 * inode) time field to zero to force revalidate on parent
		 * directory faster ie
		 *
		 * CIFS_I(inode)->time = 0;
		 */
	}

cifs_hl_exit:
	kfree(from_name);
	kfree(to_name);
	free_xid(xid);
	cifs_put_tlink(tlink);
	return rc;
}

void *
cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
{
	struct inode *inode = direntry->d_inode;
	int rc = -ENOMEM;
	unsigned int xid;
	char *full_path = NULL;
	char *target_path = NULL;
	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
	struct tcon_link *tlink = NULL;
	struct cifs_tcon *tcon;
	struct TCP_Server_Info *server;

	xid = get_xid();

	tlink = cifs_sb_tlink(cifs_sb);
	if (IS_ERR(tlink)) {
		rc = PTR_ERR(tlink);
		tlink = NULL;
		goto out;
	}
	tcon = tlink_tcon(tlink);
	server = tcon->ses->server;

	full_path = build_path_from_dentry(direntry);
	if (!full_path)
		goto out;

	cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);

	rc = -EACCES;
	/*
	 * First try Minshall+French Symlinks, if configured
	 * and fallback to UNIX Extensions Symlinks.
	 */
	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
		rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
				      &target_path);

	if (rc != 0 && server->ops->query_symlink)
		rc = server->ops->query_symlink(xid, tcon, full_path,
						&target_path, cifs_sb);

	kfree(full_path);
out:
	if (rc != 0) {
		kfree(target_path);
		target_path = ERR_PTR(rc);
	}

	free_xid(xid);
	if (tlink)
		cifs_put_tlink(tlink);
	nd_set_link(nd, target_path);
	return NULL;
}

int
cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
{
	int rc = -EOPNOTSUPP;
	unsigned int xid;
	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
	struct tcon_link *tlink;
	struct cifs_tcon *pTcon;
	char *full_path = NULL;
	struct inode *newinode = NULL;

	xid = get_xid();

	tlink = cifs_sb_tlink(cifs_sb);
	if (IS_ERR(tlink)) {
		rc = PTR_ERR(tlink);
		goto symlink_exit;
	}
	pTcon = tlink_tcon(tlink);

	full_path = build_path_from_dentry(direntry);
	if (full_path == NULL) {
		rc = -ENOMEM;
		goto symlink_exit;
	}

	cifs_dbg(FYI, "Full path: %s\n", full_path);
	cifs_dbg(FYI, "symname is %s\n", symname);

	/* BB what if DFS and this volume is on different share? BB */
	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
		rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
	else if (pTcon->unix_ext)
		rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
					   cifs_sb->local_nls);
	/* else
	   rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
					cifs_sb_target->local_nls); */

	if (rc == 0) {
		if (pTcon->unix_ext)
			rc = cifs_get_inode_info_unix(&newinode, full_path,
						      inode->i_sb, xid);
		else
			rc = cifs_get_inode_info(&newinode, full_path, NULL,
						 inode->i_sb, xid, NULL);

		if (rc != 0) {
			cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
				 rc);
		} else {
			d_instantiate(direntry, newinode);
		}
	}
symlink_exit:
	kfree(full_path);
	cifs_put_tlink(tlink);
	free_xid(xid);
	return rc;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* fs/cifs/link.c
	3	*
366781c1	4	* Copyright (C) International Business Machines Corp., 2002,2008
1da177e4 LT	5	* Author(s): Steve French (sfrench@us.ibm.com)
	6	*
	7	* This library is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU Lesser General Public License as published
	9	* by the Free Software Foundation; either version 2.1 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This library is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
	15	* the GNU Lesser General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU Lesser General Public License
	18	* along with this library; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*/
	21	#include <linux/fs.h>
	22	#include <linux/stat.h>
5a0e3ad6	23	#include <linux/slab.h>
1da177e4 LT	24	#include <linux/namei.h>
	25	#include "cifsfs.h"
	26	#include "cifspdu.h"
	27	#include "cifsglob.h"
	28	#include "cifsproto.h"
	29	#include "cifs_debug.h"
	30	#include "cifs_fs_sb.h"
c69c1b6e	31
0f8dce1c SP	32	/*
	33	* M-F Symlink Functions - Begin
	34	*/
	35
c69c1b6e SM	36	#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
	37	#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
	38	#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
	39	#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
	40	#define CIFS_MF_SYMLINK_FILE_SIZE \
	41	(CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
	42
	43	#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
	44	#define CIFS_MF_SYMLINK_MD5_FORMAT \
	45	"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
	46	#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
	47	md5_hash[0], md5_hash[1], md5_hash[2], md5_hash[3], \
	48	md5_hash[4], md5_hash[5], md5_hash[6], md5_hash[7], \
	49	md5_hash[8], md5_hash[9], md5_hash[10], md5_hash[11],\
	50	md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]
	51
93c100c0 SF	52	static int
	53	symlink_hash(unsigned int link_len, const char link_str, u8 md5_hash)
	54	{
	55	int rc;
	56	unsigned int size;
	57	struct crypto_shash *md5;
	58	struct sdesc *sdescmd5;
	59
	60	md5 = crypto_alloc_shash("md5", 0, 0);
ee2c9258	61	if (IS_ERR(md5)) {
ffeb414a	62	rc = PTR_ERR(md5);
f96637be JP	63	cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n",
f96637be JP	64	__func__, rc);
ffeb414a	65	return rc;
93c100c0 SF	66	}
	67	size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
	68	sdescmd5 = kmalloc(size, GFP_KERNEL);
	69	if (!sdescmd5) {
	70	rc = -ENOMEM;
93c100c0 SF	71	goto symlink_hash_err;
	72	}
	73	sdescmd5->shash.tfm = md5;
	74	sdescmd5->shash.flags = 0x0;
	75
	76	rc = crypto_shash_init(&sdescmd5->shash);
	77	if (rc) {
f96637be	78	cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
93c100c0 SF	79	goto symlink_hash_err;
93c100c0 SF	80	}
14cae324 SP	81	rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
14cae324 SP	82	if (rc) {
f96637be	83	cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
14cae324 SP	84	goto symlink_hash_err;
14cae324 SP	85	}
93c100c0	86	rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
14cae324	87	if (rc)
f96637be	88	cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
93c100c0 SF	89
	90	symlink_hash_err:
	91	crypto_free_shash(md5);
	92	kfree(sdescmd5);
	93
	94	return rc;
	95	}
	96
c69c1b6e	97	static int
cb084b1a SP	98	parse_mf_symlink(const u8 buf, unsigned int buf_len, unsigned int _link_len,
cb084b1a SP	99	char **_link_str)
c69c1b6e SM	100	{
	101	int rc;
	102	unsigned int link_len;
	103	const char *md5_str1;
	104	const char *link_str;
c69c1b6e SM	105	u8 md5_hash[16];
	106	char md5_str2[34];
	107
	108	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
	109	return -EINVAL;
	110
	111	md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
	112	link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
	113
	114	rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
	115	if (rc != 1)
	116	return -EINVAL;
	117
93c100c0 SF	118	rc = symlink_hash(link_len, link_str, md5_hash);
93c100c0 SF	119	if (rc) {
f96637be	120	cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
93c100c0 SF	121	return rc;
93c100c0 SF	122	}
c69c1b6e SM	123
	124	snprintf(md5_str2, sizeof(md5_str2),
	125	CIFS_MF_SYMLINK_MD5_FORMAT,
	126	CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
	127
	128	if (strncmp(md5_str1, md5_str2, 17) != 0)
	129	return -EINVAL;
	130
	131	if (_link_str) {
	132	*_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
	133	if (!*_link_str)
	134	return -ENOMEM;
	135	}
	136
	137	*_link_len = link_len;
	138	return 0;
	139	}
1da177e4	140
0fd43ae4	141	static int
cb084b1a	142	format_mf_symlink(u8 buf, unsigned int buf_len, const char link_str)
18bddd10	143	{
93c100c0	144	int rc;
18bddd10 SM	145	unsigned int link_len;
18bddd10 SM	146	unsigned int ofs;
18bddd10 SM	147	u8 md5_hash[16];
	148
	149	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
	150	return -EINVAL;
	151
	152	link_len = strlen(link_str);
	153
	154	if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
	155	return -ENAMETOOLONG;
	156
93c100c0 SF	157	rc = symlink_hash(link_len, link_str, md5_hash);
93c100c0 SF	158	if (rc) {
f96637be	159	cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
93c100c0 SF	160	return rc;
93c100c0 SF	161	}
18bddd10 SM	162
	163	snprintf(buf, buf_len,
	164	CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
	165	link_len,
	166	CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
	167
	168	ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
	169	memcpy(buf + ofs, link_str, link_len);
	170
	171	ofs += link_len;
	172	if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
	173	buf[ofs] = '\n';
	174	ofs++;
	175	}
	176
	177	while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
	178	buf[ofs] = ' ';
	179	ofs++;
	180	}
	181
	182	return 0;
	183	}
	184
0f8dce1c SP	185	bool
	186	couldbe_mf_symlink(const struct cifs_fattr *fattr)
	187	{
a9a315d4	188	if (!S_ISREG(fattr->cf_mode))
0f8dce1c SP	189	/* it's not a symlink */
	190	return false;
	191
	192	if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
	193	/* it's not a symlink */
	194	return false;
	195
	196	return true;
	197	}
	198
8713d01d	199	static int
cb084b1a	200	create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
cbb0aba6 SP	201	struct cifs_sb_info cifs_sb, const char fromName,
cbb0aba6 SP	202	const char *toName)
8713d01d SM	203	{
8713d01d SM	204	int rc;
8713d01d SM	205	u8 *buf;
	206	unsigned int bytes_written = 0;
	207
	208	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	209	if (!buf)
	210	return -ENOMEM;
	211
cb084b1a	212	rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
cbb0aba6 SP	213	if (rc)
cbb0aba6 SP	214	goto out;
fa2989f4	215
da80659d SF	216	if (tcon->ses->server->ops->create_mf_symlink)
	217	rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
	218	cifs_sb, fromName, buf, &bytes_written);
	219	else
	220	rc = -EOPNOTSUPP;
	221
cbb0aba6 SP	222	if (rc)
cbb0aba6 SP	223	goto out;
8713d01d SM	224
8713d01d SM	225	if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
cbb0aba6 SP	226	rc = -EIO;
	227	out:
	228	kfree(buf);
	229	return rc;
8713d01d SM	230	}
	231
	232	static int
cb084b1a	233	query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
8205d1bb SP	234	struct cifs_sb_info cifs_sb, const unsigned char path,
8205d1bb SP	235	char **symlinkinfo)
0fd43ae4 SM	236	{
0fd43ae4 SM	237	int rc;
8205d1bb	238	u8 *buf = NULL;
0fd43ae4	239	unsigned int link_len = 0;
8205d1bb	240	unsigned int bytes_read = 0;
0fd43ae4 SM	241
	242	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	243	if (!buf)
	244	return -ENOMEM;
0fd43ae4	245
8205d1bb SP	246	if (tcon->ses->server->ops->query_mf_symlink)
	247	rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
	248	cifs_sb, path, buf, &bytes_read);
	249	else
	250	rc = -ENOSYS;
	251
	252	if (rc)
	253	goto out;
	254
	255	if (bytes_read == 0) { /* not a symlink */
	256	rc = -EINVAL;
	257	goto out;
0fd43ae4 SM	258	}
0fd43ae4 SM	259
cb084b1a	260	rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
8205d1bb	261	out:
0fd43ae4	262	kfree(buf);
8205d1bb	263	return rc;
0fd43ae4 SM	264	}
0fd43ae4 SM	265
0f8dce1c SP	266	int
	267	check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
	268	struct cifs_sb_info cifs_sb, struct cifs_fattr fattr,
	269	const unsigned char *path)
8bfb50a8	270	{
0f8dce1c SP	271	int rc;
	272	u8 *buf = NULL;
	273	unsigned int link_len = 0;
	274	unsigned int bytes_read = 0;
	275
	276	if (!couldbe_mf_symlink(fattr))
8bfb50a8	277	/* it's not a symlink */
0f8dce1c	278	return 0;
8bfb50a8	279
0f8dce1c SP	280	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	281	if (!buf)
	282	return -ENOMEM;
	283
	284	if (tcon->ses->server->ops->query_mf_symlink)
	285	rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
	286	cifs_sb, path, buf, &bytes_read);
	287	else
	288	rc = -ENOSYS;
	289
	290	if (rc)
	291	goto out;
	292
	293	if (bytes_read == 0) /* not a symlink */
	294	goto out;
	295
	296	rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
	297	if (rc == -EINVAL) {
8bfb50a8	298	/* it's not a symlink */
0f8dce1c SP	299	rc = 0;
	300	goto out;
	301	}
8bfb50a8	302
0f8dce1c SP	303	if (rc != 0)
	304	goto out;
	305
	306	/* it is a symlink */
	307	fattr->cf_eof = link_len;
	308	fattr->cf_mode &= ~S_IFMT;
	309	fattr->cf_mode \|= S_IFLNK \| S_IRWXU \| S_IRWXG \| S_IRWXO;
	310	fattr->cf_dtype = DT_LNK;
	311	out:
	312	kfree(buf);
	313	return rc;
8bfb50a8 SM	314	}
8bfb50a8 SM	315
0f8dce1c SP	316	/*
	317	* SMB 1.0 Protocol specific functions
	318	*/
	319
8bfb50a8	320	int
b5be1a1c SP	321	cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
	322	struct cifs_sb_info cifs_sb, const unsigned char path,
	323	char pbuf, unsigned int pbytes_read)
8bfb50a8 SM	324	{
	325	int rc;
	326	int oplock = 0;
d81b8a40 PS	327	struct cifs_fid fid;
d81b8a40 PS	328	struct cifs_open_parms oparms;
d4ffff1f	329	struct cifs_io_parms io_parms;
8bfb50a8	330	int buf_type = CIFS_NO_BUFFER;
8bfb50a8 SM	331	FILE_ALL_INFO file_info;
8bfb50a8 SM	332
d81b8a40 PS	333	oparms.tcon = tcon;
	334	oparms.cifs_sb = cifs_sb;
	335	oparms.desired_access = GENERIC_READ;
	336	oparms.create_options = CREATE_NOT_DIR;
	337	oparms.disposition = FILE_OPEN;
	338	oparms.path = path;
	339	oparms.fid = &fid;
	340	oparms.reconnect = false;
	341
	342	rc = CIFS_open(xid, &oparms, &oplock, &file_info);
b5be1a1c	343	if (rc)
1b244081	344	return rc;
8bfb50a8	345
364d4293 SF	346	if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
364d4293 SF	347	rc = -ENOENT;
8bfb50a8	348	/* it's not a symlink */
b5be1a1c	349	goto out;
364d4293	350	}
8bfb50a8	351
d81b8a40	352	io_parms.netfid = fid.netfid;
d4ffff1f	353	io_parms.pid = current->tgid;
b5be1a1c	354	io_parms.tcon = tcon;
d4ffff1f PS	355	io_parms.offset = 0;
d4ffff1f PS	356	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
8bfb50a8	357
1b244081	358	rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
b5be1a1c	359	out:
d81b8a40	360	CIFSSMBClose(xid, tcon, fid.netfid);
1b244081 SF	361	return rc;
	362	}
	363
cbb0aba6 SP	364	int
	365	cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
	366	struct cifs_sb_info cifs_sb, const unsigned char path,
	367	char pbuf, unsigned int pbytes_written)
	368	{
	369	int rc;
	370	int oplock = 0;
d81b8a40 PS	371	struct cifs_fid fid;
d81b8a40 PS	372	struct cifs_open_parms oparms;
cbb0aba6 SP	373	struct cifs_io_parms io_parms;
	374	int create_options = CREATE_NOT_DIR;
	375
	376	if (backup_cred(cifs_sb))
	377	create_options \|= CREATE_OPEN_BACKUP_INTENT;
	378
d81b8a40 PS	379	oparms.tcon = tcon;
	380	oparms.cifs_sb = cifs_sb;
	381	oparms.desired_access = GENERIC_WRITE;
	382	oparms.create_options = create_options;
a1d0b84c	383	oparms.disposition = FILE_CREATE;
d81b8a40 PS	384	oparms.path = path;
	385	oparms.fid = &fid;
	386	oparms.reconnect = false;
	387
	388	rc = CIFS_open(xid, &oparms, &oplock, NULL);
cbb0aba6 SP	389	if (rc)
	390	return rc;
	391
d81b8a40	392	io_parms.netfid = fid.netfid;
cbb0aba6 SP	393	io_parms.pid = current->tgid;
	394	io_parms.tcon = tcon;
	395	io_parms.offset = 0;
	396	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
	397
	398	rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf, NULL, 0);
d81b8a40	399	CIFSSMBClose(xid, tcon, fid.netfid);
cbb0aba6 SP	400	return rc;
	401	}
	402
0f8dce1c SP	403	/*
	404	* M-F Symlink Functions - End
	405	*/
8bfb50a8	406
1da177e4 LT	407	int
	408	cifs_hardlink(struct dentry old_file, struct inode inode,
	409	struct dentry *direntry)
	410	{
	411	int rc = -EACCES;
6d5786a3	412	unsigned int xid;
d6e906f1 SF	413	char *from_name = NULL;
d6e906f1 SF	414	char *to_name = NULL;
7ffec372 JL	415	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
7ffec372 JL	416	struct tcon_link *tlink;
d6e906f1 SF	417	struct cifs_tcon *tcon;
d6e906f1 SF	418	struct TCP_Server_Info *server;
1da177e4 LT	419	struct cifsInodeInfo *cifsInode;
1da177e4 LT	420
7ffec372 JL	421	tlink = cifs_sb_tlink(cifs_sb);
	422	if (IS_ERR(tlink))
	423	return PTR_ERR(tlink);
d6e906f1	424	tcon = tlink_tcon(tlink);
1da177e4	425
6d5786a3	426	xid = get_xid();
1da177e4	427
d6e906f1 SF	428	from_name = build_path_from_dentry(old_file);
	429	to_name = build_path_from_dentry(direntry);
	430	if ((from_name == NULL) \|\| (to_name == NULL)) {
1da177e4 LT	431	rc = -ENOMEM;
	432	goto cifs_hl_exit;
	433	}
	434
d6e906f1 SF	435	if (tcon->unix_ext)
d6e906f1 SF	436	rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
7ffec372 JL	437	cifs_sb->local_nls,
7ffec372 JL	438	cifs_sb->mnt_cifs_flags &
737b758c	439	CIFS_MOUNT_MAP_SPECIAL_CHR);
1da177e4	440	else {
d6e906f1	441	server = tcon->ses->server;
abf9767c CE	442	if (!server->ops->create_hardlink) {
	443	rc = -ENOSYS;
	444	goto cifs_hl_exit;
	445	}
d6e906f1 SF	446	rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
d6e906f1 SF	447	cifs_sb);
fb8c4b14 SF	448	if ((rc == -EIO) \|\| (rc == -EINVAL))
fb8c4b14 SF	449	rc = -EOPNOTSUPP;
1da177e4 LT	450	}
1da177e4 LT	451
31ec35d6 SF	452	d_drop(direntry); /* force new lookup from server of target */
31ec35d6 SF	453
d6e906f1 SF	454	/*
	455	* if source file is cached (oplocked) revalidate will not go to server
	456	* until the file is closed or oplock broken so update nlinks locally
	457	*/
fb8c4b14	458	if (old_file->d_inode) {
31ec35d6	459	cifsInode = CIFS_I(old_file->d_inode);
fb8c4b14	460	if (rc == 0) {
b7ca6928	461	spin_lock(&old_file->d_inode->i_lock);
6d6b77f1	462	inc_nlink(old_file->d_inode);
b7ca6928	463	spin_unlock(&old_file->d_inode->i_lock);
d6e906f1 SF	464	/*
	465	* BB should we make this contingent on superblock flag
	466	* NOATIME?
	467	*/
	468	/* old_file->d_inode->i_ctime = CURRENT_TIME; */
	469	/*
	470	* parent dir timestamps will update from srv within a
	471	* second, would it really be worth it to set the parent
	472	* dir cifs inode time to zero to force revalidate
	473	* (faster) for it too?
	474	*/
31ec35d6	475	}
d6e906f1 SF	476	/*
	477	* if not oplocked will force revalidate to get info on source
	478	* file from srv
	479	*/
31ec35d6 SF	480	cifsInode->time = 0;
31ec35d6 SF	481
d6e906f1 SF	482	/*
	483	* Will update parent dir timestamps from srv within a second.
	484	* Would it really be worth it to set the parent dir (cifs
	485	* inode) time field to zero to force revalidate on parent
	486	* directory faster ie
	487	*
	488	* CIFS_I(inode)->time = 0;
	489	*/
1da177e4	490	}
1da177e4 LT	491
1da177e4 LT	492	cifs_hl_exit:
d6e906f1 SF	493	kfree(from_name);
d6e906f1 SF	494	kfree(to_name);
6d5786a3	495	free_xid(xid);
7ffec372	496	cifs_put_tlink(tlink);
1da177e4 LT	497	return rc;
	498	}
	499
cc314eef	500	void *
1da177e4 LT	501	cifs_follow_link(struct dentry direntry, struct nameidata nd)
	502	{
	503	struct inode *inode = direntry->d_inode;
8b6427a2	504	int rc = -ENOMEM;
6d5786a3	505	unsigned int xid;
1da177e4	506	char *full_path = NULL;
8b6427a2 JL	507	char *target_path = NULL;
8b6427a2 JL	508	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
7ffec372	509	struct tcon_link *tlink = NULL;
96daf2b0	510	struct cifs_tcon *tcon;
b42bf888	511	struct TCP_Server_Info *server;
1da177e4	512
6d5786a3	513	xid = get_xid();
1da177e4	514
7ffec372 JL	515	tlink = cifs_sb_tlink(cifs_sb);
	516	if (IS_ERR(tlink)) {
	517	rc = PTR_ERR(tlink);
	518	tlink = NULL;
	519	goto out;
	520	}
	521	tcon = tlink_tcon(tlink);
b42bf888	522	server = tcon->ses->server;
1da177e4	523
8b6427a2	524	full_path = build_path_from_dentry(direntry);
1da177e4	525	if (!full_path)
460b9696	526	goto out;
1da177e4	527
f96637be	528	cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
1da177e4	529
1b12b9c1 SM	530	rc = -EACCES;
	531	/*
	532	* First try Minshall+French Symlinks, if configured
	533	* and fallback to UNIX Extensions Symlinks.
	534	*/
	535	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
8205d1bb SP	536	rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
8205d1bb SP	537	&target_path);
1b12b9c1	538
0ecdb4f5	539	if (rc != 0 && server->ops->query_symlink)
b42bf888 PS	540	rc = server->ops->query_symlink(xid, tcon, full_path,
b42bf888 PS	541	&target_path, cifs_sb);
1b12b9c1	542
8b6427a2 JL	543	kfree(full_path);
8b6427a2 JL	544	out:
460b9696	545	if (rc != 0) {
1da177e4 LT	546	kfree(target_path);
	547	target_path = ERR_PTR(rc);
	548	}
	549
6d5786a3	550	free_xid(xid);
7ffec372 JL	551	if (tlink)
7ffec372 JL	552	cifs_put_tlink(tlink);
1da177e4	553	nd_set_link(nd, target_path);
460b9696	554	return NULL;
1da177e4 LT	555	}
	556
	557	int
	558	cifs_symlink(struct inode inode, struct dentry direntry, const char *symname)
	559	{
	560	int rc = -EOPNOTSUPP;
6d5786a3	561	unsigned int xid;
7ffec372 JL	562	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
7ffec372 JL	563	struct tcon_link *tlink;
96daf2b0	564	struct cifs_tcon *pTcon;
1da177e4 LT	565	char *full_path = NULL;
	566	struct inode *newinode = NULL;
	567
6d5786a3	568	xid = get_xid();
1da177e4	569
7ffec372 JL	570	tlink = cifs_sb_tlink(cifs_sb);
	571	if (IS_ERR(tlink)) {
	572	rc = PTR_ERR(tlink);
	573	goto symlink_exit;
	574	}
	575	pTcon = tlink_tcon(tlink);
1da177e4	576
7f57356b	577	full_path = build_path_from_dentry(direntry);
fb8c4b14	578	if (full_path == NULL) {
0f3bc09e	579	rc = -ENOMEM;
7ffec372	580	goto symlink_exit;
1da177e4 LT	581	}
1da177e4 LT	582
f96637be JP	583	cifs_dbg(FYI, "Full path: %s\n", full_path);
f96637be JP	584	cifs_dbg(FYI, "symname is %s\n", symname);
1da177e4 LT	585
1da177e4 LT	586	/* BB what if DFS and this volume is on different share? BB */
1b12b9c1	587	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
cbb0aba6	588	rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
1b12b9c1	589	else if (pTcon->unix_ext)
1da177e4 LT	590	rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
	591	cifs_sb->local_nls);
	592	/* else
fb8c4b14 SF	593	rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
fb8c4b14 SF	594	cifs_sb_target->local_nls); */
1da177e4 LT	595
1da177e4 LT	596	if (rc == 0) {
c18c842b	597	if (pTcon->unix_ext)
1da177e4	598	rc = cifs_get_inode_info_unix(&newinode, full_path,
fb8c4b14	599	inode->i_sb, xid);
1da177e4 LT	600	else
1da177e4 LT	601	rc = cifs_get_inode_info(&newinode, full_path, NULL,
8b1327f6	602	inode->i_sb, xid, NULL);
1da177e4 LT	603
1da177e4 LT	604	if (rc != 0) {
f96637be JP	605	cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
f96637be JP	606	rc);
1da177e4	607	} else {
1da177e4 LT	608	d_instantiate(direntry, newinode);
	609	}
	610	}
7ffec372	611	symlink_exit:
f99d49ad	612	kfree(full_path);
7ffec372	613	cifs_put_tlink(tlink);
6d5786a3	614	free_xid(xid);
1da177e4 LT	615	return rc;
1da177e4 LT	616	}