[linux-2.6-block.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"

#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;
}

static int
create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
		    const char *fromName, const char *toName,
		    struct cifs_sb_info *cifs_sb)
{
	int rc;
	int oplock = 0;
	int remap;
	int create_options = CREATE_NOT_DIR;
	__u16 netfid = 0;
	u8 *buf;
	unsigned int bytes_written = 0;
	struct cifs_io_parms io_parms;
	struct nls_table *nls_codepage;

	nls_codepage = cifs_sb->local_nls;
	remap = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR;

	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 != 0) {
		kfree(buf);
		return rc;
	}

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

	rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
			 create_options, &netfid, &oplock, NULL,
			 nls_codepage, remap);
	if (rc != 0) {
		kfree(buf);
		return rc;
	}

	io_parms.netfid = 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, &bytes_written, buf, NULL, 0);
	CIFSSMBClose(xid, tcon, netfid);
	kfree(buf);
	if (rc != 0)
		return rc;

	if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
		return -EIO;

	return 0;
}

static int
query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
		   const unsigned char *searchName, char **symlinkinfo,
		   const struct nls_table *nls_codepage, int remap)
{
	int rc;
	int oplock = 0;
	__u16 netfid = 0;
	u8 *buf;
	char *pbuf;
	unsigned int bytes_read = 0;
	int buf_type = CIFS_NO_BUFFER;
	unsigned int link_len = 0;
	struct cifs_io_parms io_parms;
	FILE_ALL_INFO file_info;

	rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
			 nls_codepage, remap);
	if (rc != 0)
		return rc;

	if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
		CIFSSMBClose(xid, tcon, netfid);
		/* it's not a symlink */
		return -EINVAL;
	}

	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	pbuf = buf;
	io_parms.netfid = 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, &bytes_read, &pbuf, &buf_type);
	CIFSSMBClose(xid, tcon, netfid);
	if (rc != 0) {
		kfree(buf);
		return rc;
	}

	rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
	kfree(buf);
	if (rc != 0)
		return rc;

	return 0;
}

bool
couldbe_mf_symlink(const struct cifs_fattr *fattr)
{
	if (!(fattr->cf_mode & S_IFREG))
		/* 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;
}

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;
	__u16 netfid = 0;
	struct cifs_io_parms io_parms;
	int buf_type = CIFS_NO_BUFFER;
	FILE_ALL_INFO file_info;

	rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, GENERIC_READ,
			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
			 cifs_sb->local_nls,
			 cifs_sb->mnt_cifs_flags &
				CIFS_MOUNT_MAP_SPECIAL_CHR);
	if (rc)
		return rc;

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

	io_parms.netfid = 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, netfid);
	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;
}

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, full_path, &target_path,
					cifs_sb->local_nls,
					cifs_sb->mnt_cifs_flags &
						CIFS_MOUNT_MAP_SPECIAL_CHR);

	if ((rc != 0) && cap_unix(tcon->ses))
		rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
					     cifs_sb->local_nls);
	else 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, full_path, symname,
					cifs_sb);
	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 SM	31
	32	#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
	33	#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
	34	#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
	35	#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
	36	#define CIFS_MF_SYMLINK_FILE_SIZE \
	37	(CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
	38
	39	#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
	40	#define CIFS_MF_SYMLINK_MD5_FORMAT \
	41	"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
	42	#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
	43	md5_hash[0], md5_hash[1], md5_hash[2], md5_hash[3], \
	44	md5_hash[4], md5_hash[5], md5_hash[6], md5_hash[7], \
	45	md5_hash[8], md5_hash[9], md5_hash[10], md5_hash[11],\
	46	md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]
	47
93c100c0 SF	48	static int
	49	symlink_hash(unsigned int link_len, const char link_str, u8 md5_hash)
	50	{
	51	int rc;
	52	unsigned int size;
	53	struct crypto_shash *md5;
	54	struct sdesc *sdescmd5;
	55
	56	md5 = crypto_alloc_shash("md5", 0, 0);
ee2c9258	57	if (IS_ERR(md5)) {
ffeb414a	58	rc = PTR_ERR(md5);
f96637be JP	59	cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n",
f96637be JP	60	__func__, rc);
ffeb414a	61	return rc;
93c100c0 SF	62	}
	63	size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
	64	sdescmd5 = kmalloc(size, GFP_KERNEL);
	65	if (!sdescmd5) {
	66	rc = -ENOMEM;
93c100c0 SF	67	goto symlink_hash_err;
	68	}
	69	sdescmd5->shash.tfm = md5;
	70	sdescmd5->shash.flags = 0x0;
	71
	72	rc = crypto_shash_init(&sdescmd5->shash);
	73	if (rc) {
f96637be	74	cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
93c100c0 SF	75	goto symlink_hash_err;
93c100c0 SF	76	}
14cae324 SP	77	rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
14cae324 SP	78	if (rc) {
f96637be	79	cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
14cae324 SP	80	goto symlink_hash_err;
14cae324 SP	81	}
93c100c0	82	rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
14cae324	83	if (rc)
f96637be	84	cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
93c100c0 SF	85
	86	symlink_hash_err:
	87	crypto_free_shash(md5);
	88	kfree(sdescmd5);
	89
	90	return rc;
	91	}
	92
c69c1b6e	93	static int
cb084b1a SP	94	parse_mf_symlink(const u8 buf, unsigned int buf_len, unsigned int _link_len,
cb084b1a SP	95	char **_link_str)
c69c1b6e SM	96	{
	97	int rc;
	98	unsigned int link_len;
	99	const char *md5_str1;
	100	const char *link_str;
c69c1b6e SM	101	u8 md5_hash[16];
	102	char md5_str2[34];
	103
	104	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
	105	return -EINVAL;
	106
	107	md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
	108	link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
	109
	110	rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
	111	if (rc != 1)
	112	return -EINVAL;
	113
93c100c0 SF	114	rc = symlink_hash(link_len, link_str, md5_hash);
93c100c0 SF	115	if (rc) {
f96637be	116	cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
93c100c0 SF	117	return rc;
93c100c0 SF	118	}
c69c1b6e SM	119
	120	snprintf(md5_str2, sizeof(md5_str2),
	121	CIFS_MF_SYMLINK_MD5_FORMAT,
	122	CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
	123
	124	if (strncmp(md5_str1, md5_str2, 17) != 0)
	125	return -EINVAL;
	126
	127	if (_link_str) {
	128	*_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
	129	if (!*_link_str)
	130	return -ENOMEM;
	131	}
	132
	133	*_link_len = link_len;
	134	return 0;
	135	}
1da177e4	136
0fd43ae4	137	static int
cb084b1a	138	format_mf_symlink(u8 buf, unsigned int buf_len, const char link_str)
18bddd10	139	{
93c100c0	140	int rc;
18bddd10 SM	141	unsigned int link_len;
18bddd10 SM	142	unsigned int ofs;
18bddd10 SM	143	u8 md5_hash[16];
	144
	145	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
	146	return -EINVAL;
	147
	148	link_len = strlen(link_str);
	149
	150	if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
	151	return -ENAMETOOLONG;
	152
93c100c0 SF	153	rc = symlink_hash(link_len, link_str, md5_hash);
93c100c0 SF	154	if (rc) {
f96637be	155	cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
93c100c0 SF	156	return rc;
93c100c0 SF	157	}
18bddd10 SM	158
	159	snprintf(buf, buf_len,
	160	CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
	161	link_len,
	162	CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
	163
	164	ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
	165	memcpy(buf + ofs, link_str, link_len);
	166
	167	ofs += link_len;
	168	if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
	169	buf[ofs] = '\n';
	170	ofs++;
	171	}
	172
	173	while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
	174	buf[ofs] = ' ';
	175	ofs++;
	176	}
	177
	178	return 0;
	179	}
	180
8713d01d	181	static int
cb084b1a	182	create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
8713d01d	183	const char fromName, const char toName,
3d3ea8e6	184	struct cifs_sb_info *cifs_sb)
8713d01d SM	185	{
	186	int rc;
	187	int oplock = 0;
3d3ea8e6 SP	188	int remap;
3d3ea8e6 SP	189	int create_options = CREATE_NOT_DIR;
8713d01d SM	190	__u16 netfid = 0;
	191	u8 *buf;
	192	unsigned int bytes_written = 0;
fa2989f4	193	struct cifs_io_parms io_parms;
3d3ea8e6 SP	194	struct nls_table *nls_codepage;
	195
	196	nls_codepage = cifs_sb->local_nls;
	197	remap = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR;
8713d01d SM	198
	199	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	200	if (!buf)
	201	return -ENOMEM;
	202
cb084b1a	203	rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
8713d01d SM	204	if (rc != 0) {
	205	kfree(buf);
	206	return rc;
	207	}
	208
3d3ea8e6 SP	209	if (backup_cred(cifs_sb))
	210	create_options \|= CREATE_OPEN_BACKUP_INTENT;
	211
8713d01d	212	rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
3d3ea8e6	213	create_options, &netfid, &oplock, NULL,
8713d01d SM	214	nls_codepage, remap);
	215	if (rc != 0) {
	216	kfree(buf);
	217	return rc;
	218	}
	219
fa2989f4 PS	220	io_parms.netfid = netfid;
	221	io_parms.pid = current->tgid;
	222	io_parms.tcon = tcon;
	223	io_parms.offset = 0;
	224	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
	225
	226	rc = CIFSSMBWrite(xid, &io_parms, &bytes_written, buf, NULL, 0);
8713d01d SM	227	CIFSSMBClose(xid, tcon, netfid);
	228	kfree(buf);
	229	if (rc != 0)
	230	return rc;
	231
	232	if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
	233	return -EIO;
	234
	235	return 0;
	236	}
	237
	238	static int
cb084b1a	239	query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
0fd43ae4 SM	240	const unsigned char searchName, char *symlinkinfo,
	241	const struct nls_table *nls_codepage, int remap)
	242	{
	243	int rc;
	244	int oplock = 0;
	245	__u16 netfid = 0;
	246	u8 *buf;
	247	char *pbuf;
	248	unsigned int bytes_read = 0;
	249	int buf_type = CIFS_NO_BUFFER;
	250	unsigned int link_len = 0;
d4ffff1f	251	struct cifs_io_parms io_parms;
0fd43ae4 SM	252	FILE_ALL_INFO file_info;
	253
	254	rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
	255	CREATE_NOT_DIR, &netfid, &oplock, &file_info,
	256	nls_codepage, remap);
	257	if (rc != 0)
	258	return rc;
	259
5443d130	260	if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
0fd43ae4 SM	261	CIFSSMBClose(xid, tcon, netfid);
	262	/* it's not a symlink */
	263	return -EINVAL;
	264	}
	265
	266	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	267	if (!buf)
	268	return -ENOMEM;
	269	pbuf = buf;
d4ffff1f PS	270	io_parms.netfid = netfid;
	271	io_parms.pid = current->tgid;
	272	io_parms.tcon = tcon;
	273	io_parms.offset = 0;
	274	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
0fd43ae4	275
d4ffff1f	276	rc = CIFSSMBRead(xid, &io_parms, &bytes_read, &pbuf, &buf_type);
0fd43ae4 SM	277	CIFSSMBClose(xid, tcon, netfid);
	278	if (rc != 0) {
	279	kfree(buf);
	280	return rc;
	281	}
	282
cb084b1a	283	rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
0fd43ae4 SM	284	kfree(buf);
	285	if (rc != 0)
	286	return rc;
	287
	288	return 0;
	289	}
	290
8bfb50a8	291	bool
cb084b1a	292	couldbe_mf_symlink(const struct cifs_fattr *fattr)
8bfb50a8 SM	293	{
	294	if (!(fattr->cf_mode & S_IFREG))
	295	/* it's not a symlink */
	296	return false;
	297
	298	if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
	299	/* it's not a symlink */
	300	return false;
	301
	302	return true;
	303	}
	304
	305	int
b5be1a1c SP	306	cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
	307	struct cifs_sb_info cifs_sb, const unsigned char path,
	308	char pbuf, unsigned int pbytes_read)
8bfb50a8 SM	309	{
	310	int rc;
	311	int oplock = 0;
	312	__u16 netfid = 0;
d4ffff1f	313	struct cifs_io_parms io_parms;
8bfb50a8	314	int buf_type = CIFS_NO_BUFFER;
8bfb50a8 SM	315	FILE_ALL_INFO file_info;
8bfb50a8 SM	316
b5be1a1c	317	rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, GENERIC_READ,
8bfb50a8 SM	318	CREATE_NOT_DIR, &netfid, &oplock, &file_info,
	319	cifs_sb->local_nls,
	320	cifs_sb->mnt_cifs_flags &
	321	CIFS_MOUNT_MAP_SPECIAL_CHR);
b5be1a1c	322	if (rc)
1b244081	323	return rc;
8bfb50a8	324
b5be1a1c	325	if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE))
8bfb50a8	326	/* it's not a symlink */
b5be1a1c	327	goto out;
8bfb50a8	328
d4ffff1f PS	329	io_parms.netfid = netfid;
d4ffff1f PS	330	io_parms.pid = current->tgid;
b5be1a1c	331	io_parms.tcon = tcon;
d4ffff1f PS	332	io_parms.offset = 0;
d4ffff1f PS	333	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
8bfb50a8	334
1b244081	335	rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
b5be1a1c SP	336	out:
b5be1a1c SP	337	CIFSSMBClose(xid, tcon, netfid);
1b244081 SF	338	return rc;
	339	}
	340
1b244081	341	int
cb084b1a SP	342	check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
	343	struct cifs_sb_info cifs_sb, struct cifs_fattr fattr,
	344	const unsigned char *path)
1b244081	345	{
750b8de6	346	int rc;
1b244081 SF	347	u8 *buf = NULL;
	348	unsigned int link_len = 0;
	349	unsigned int bytes_read = 0;
1b244081	350
cb084b1a	351	if (!couldbe_mf_symlink(fattr))
1b244081 SF	352	/* it's not a symlink */
	353	return 0;
	354
	355	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
750b8de6 SP	356	if (!buf)
750b8de6 SP	357	return -ENOMEM;
8bfb50a8	358
750b8de6	359	if (tcon->ses->server->ops->query_mf_symlink)
b5be1a1c SP	360	rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
b5be1a1c SP	361	cifs_sb, path, buf, &bytes_read);
1b244081	362	else
750b8de6	363	rc = -ENOSYS;
1b244081	364
750b8de6	365	if (rc)
1b244081 SF	366	goto out;
	367
	368	if (bytes_read == 0) /* not a symlink */
	369	goto out;
	370
cb084b1a	371	rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
7ffec372	372	if (rc == -EINVAL) {
8bfb50a8	373	/* it's not a symlink */
7ffec372 JL	374	rc = 0;
	375	goto out;
	376	}
	377
8bfb50a8	378	if (rc != 0)
7ffec372	379	goto out;
8bfb50a8 SM	380
	381	/* it is a symlink */
	382	fattr->cf_eof = link_len;
	383	fattr->cf_mode &= ~S_IFMT;
	384	fattr->cf_mode \|= S_IFLNK \| S_IRWXU \| S_IRWXG \| S_IRWXO;
	385	fattr->cf_dtype = DT_LNK;
7ffec372	386	out:
1b244081	387	kfree(buf);
7ffec372	388	return rc;
8bfb50a8 SM	389	}
8bfb50a8 SM	390
1da177e4 LT	391	int
	392	cifs_hardlink(struct dentry old_file, struct inode inode,
	393	struct dentry *direntry)
	394	{
	395	int rc = -EACCES;
6d5786a3	396	unsigned int xid;
d6e906f1 SF	397	char *from_name = NULL;
d6e906f1 SF	398	char *to_name = NULL;
7ffec372 JL	399	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
7ffec372 JL	400	struct tcon_link *tlink;
d6e906f1 SF	401	struct cifs_tcon *tcon;
d6e906f1 SF	402	struct TCP_Server_Info *server;
1da177e4 LT	403	struct cifsInodeInfo *cifsInode;
1da177e4 LT	404
7ffec372 JL	405	tlink = cifs_sb_tlink(cifs_sb);
	406	if (IS_ERR(tlink))
	407	return PTR_ERR(tlink);
d6e906f1	408	tcon = tlink_tcon(tlink);
1da177e4	409
6d5786a3	410	xid = get_xid();
1da177e4	411
d6e906f1 SF	412	from_name = build_path_from_dentry(old_file);
	413	to_name = build_path_from_dentry(direntry);
	414	if ((from_name == NULL) \|\| (to_name == NULL)) {
1da177e4 LT	415	rc = -ENOMEM;
	416	goto cifs_hl_exit;
	417	}
	418
d6e906f1 SF	419	if (tcon->unix_ext)
d6e906f1 SF	420	rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
7ffec372 JL	421	cifs_sb->local_nls,
7ffec372 JL	422	cifs_sb->mnt_cifs_flags &
737b758c	423	CIFS_MOUNT_MAP_SPECIAL_CHR);
1da177e4	424	else {
d6e906f1	425	server = tcon->ses->server;
abf9767c CE	426	if (!server->ops->create_hardlink) {
	427	rc = -ENOSYS;
	428	goto cifs_hl_exit;
	429	}
d6e906f1 SF	430	rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
d6e906f1 SF	431	cifs_sb);
fb8c4b14 SF	432	if ((rc == -EIO) \|\| (rc == -EINVAL))
fb8c4b14 SF	433	rc = -EOPNOTSUPP;
1da177e4 LT	434	}
1da177e4 LT	435
31ec35d6 SF	436	d_drop(direntry); /* force new lookup from server of target */
31ec35d6 SF	437
d6e906f1 SF	438	/*
	439	* if source file is cached (oplocked) revalidate will not go to server
	440	* until the file is closed or oplock broken so update nlinks locally
	441	*/
fb8c4b14	442	if (old_file->d_inode) {
31ec35d6	443	cifsInode = CIFS_I(old_file->d_inode);
fb8c4b14	444	if (rc == 0) {
b7ca6928	445	spin_lock(&old_file->d_inode->i_lock);
6d6b77f1	446	inc_nlink(old_file->d_inode);
b7ca6928	447	spin_unlock(&old_file->d_inode->i_lock);
d6e906f1 SF	448	/*
	449	* BB should we make this contingent on superblock flag
	450	* NOATIME?
	451	*/
	452	/* old_file->d_inode->i_ctime = CURRENT_TIME; */
	453	/*
	454	* parent dir timestamps will update from srv within a
	455	* second, would it really be worth it to set the parent
	456	* dir cifs inode time to zero to force revalidate
	457	* (faster) for it too?
	458	*/
31ec35d6	459	}
d6e906f1 SF	460	/*
	461	* if not oplocked will force revalidate to get info on source
	462	* file from srv
	463	*/
31ec35d6 SF	464	cifsInode->time = 0;
31ec35d6 SF	465
d6e906f1 SF	466	/*
	467	* Will update parent dir timestamps from srv within a second.
	468	* Would it really be worth it to set the parent dir (cifs
	469	* inode) time field to zero to force revalidate on parent
	470	* directory faster ie
	471	*
	472	* CIFS_I(inode)->time = 0;
	473	*/
1da177e4	474	}
1da177e4 LT	475
1da177e4 LT	476	cifs_hl_exit:
d6e906f1 SF	477	kfree(from_name);
d6e906f1 SF	478	kfree(to_name);
6d5786a3	479	free_xid(xid);
7ffec372	480	cifs_put_tlink(tlink);
1da177e4 LT	481	return rc;
	482	}
	483
cc314eef	484	void *
1da177e4 LT	485	cifs_follow_link(struct dentry direntry, struct nameidata nd)
	486	{
	487	struct inode *inode = direntry->d_inode;
8b6427a2	488	int rc = -ENOMEM;
6d5786a3	489	unsigned int xid;
1da177e4	490	char *full_path = NULL;
8b6427a2 JL	491	char *target_path = NULL;
8b6427a2 JL	492	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
7ffec372	493	struct tcon_link *tlink = NULL;
96daf2b0	494	struct cifs_tcon *tcon;
b42bf888	495	struct TCP_Server_Info *server;
1da177e4	496
6d5786a3	497	xid = get_xid();
1da177e4	498
7ffec372 JL	499	tlink = cifs_sb_tlink(cifs_sb);
	500	if (IS_ERR(tlink)) {
	501	rc = PTR_ERR(tlink);
	502	tlink = NULL;
	503	goto out;
	504	}
	505	tcon = tlink_tcon(tlink);
b42bf888	506	server = tcon->ses->server;
1da177e4	507
8b6427a2	508	full_path = build_path_from_dentry(direntry);
1da177e4	509	if (!full_path)
460b9696	510	goto out;
1da177e4	511
f96637be	512	cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
1da177e4	513
1b12b9c1 SM	514	rc = -EACCES;
	515	/*
	516	* First try Minshall+French Symlinks, if configured
	517	* and fallback to UNIX Extensions Symlinks.
	518	*/
	519	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
cb084b1a	520	rc = query_mf_symlink(xid, tcon, full_path, &target_path,
1b12b9c1 SM	521	cifs_sb->local_nls,
	522	cifs_sb->mnt_cifs_flags &
	523	CIFS_MOUNT_MAP_SPECIAL_CHR);
	524
29e20f9c	525	if ((rc != 0) && cap_unix(tcon->ses))
1b12b9c1 SM	526	rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
1b12b9c1 SM	527	cifs_sb->local_nls);
b42bf888 PS	528	else if (rc != 0 && server->ops->query_symlink)
	529	rc = server->ops->query_symlink(xid, tcon, full_path,
	530	&target_path, cifs_sb);
1b12b9c1	531
8b6427a2 JL	532	kfree(full_path);
8b6427a2 JL	533	out:
460b9696	534	if (rc != 0) {
1da177e4 LT	535	kfree(target_path);
	536	target_path = ERR_PTR(rc);
	537	}
	538
6d5786a3	539	free_xid(xid);
7ffec372 JL	540	if (tlink)
7ffec372 JL	541	cifs_put_tlink(tlink);
1da177e4	542	nd_set_link(nd, target_path);
460b9696	543	return NULL;
1da177e4 LT	544	}
	545
	546	int
	547	cifs_symlink(struct inode inode, struct dentry direntry, const char *symname)
	548	{
	549	int rc = -EOPNOTSUPP;
6d5786a3	550	unsigned int xid;
7ffec372 JL	551	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
7ffec372 JL	552	struct tcon_link *tlink;
96daf2b0	553	struct cifs_tcon *pTcon;
1da177e4 LT	554	char *full_path = NULL;
	555	struct inode *newinode = NULL;
	556
6d5786a3	557	xid = get_xid();
1da177e4	558
7ffec372 JL	559	tlink = cifs_sb_tlink(cifs_sb);
	560	if (IS_ERR(tlink)) {
	561	rc = PTR_ERR(tlink);
	562	goto symlink_exit;
	563	}
	564	pTcon = tlink_tcon(tlink);
1da177e4	565
7f57356b	566	full_path = build_path_from_dentry(direntry);
fb8c4b14	567	if (full_path == NULL) {
0f3bc09e	568	rc = -ENOMEM;
7ffec372	569	goto symlink_exit;
1da177e4 LT	570	}
1da177e4 LT	571
f96637be JP	572	cifs_dbg(FYI, "Full path: %s\n", full_path);
f96637be JP	573	cifs_dbg(FYI, "symname is %s\n", symname);
1da177e4 LT	574
1da177e4 LT	575	/* BB what if DFS and this volume is on different share? BB */
1b12b9c1	576	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
cb084b1a	577	rc = create_mf_symlink(xid, pTcon, full_path, symname,
3d3ea8e6	578	cifs_sb);
1b12b9c1	579	else if (pTcon->unix_ext)
1da177e4 LT	580	rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
	581	cifs_sb->local_nls);
	582	/* else
fb8c4b14 SF	583	rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
fb8c4b14 SF	584	cifs_sb_target->local_nls); */
1da177e4 LT	585
1da177e4 LT	586	if (rc == 0) {
c18c842b	587	if (pTcon->unix_ext)
1da177e4	588	rc = cifs_get_inode_info_unix(&newinode, full_path,
fb8c4b14	589	inode->i_sb, xid);
1da177e4 LT	590	else
1da177e4 LT	591	rc = cifs_get_inode_info(&newinode, full_path, NULL,
8b1327f6	592	inode->i_sb, xid, NULL);
1da177e4 LT	593
1da177e4 LT	594	if (rc != 0) {
f96637be JP	595	cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
f96637be JP	596	rc);
1da177e4	597	} else {
1da177e4 LT	598	d_instantiate(direntry, newinode);
	599	}
	600	}
7ffec372	601	symlink_exit:
f99d49ad	602	kfree(full_path);
7ffec372	603	cifs_put_tlink(tlink);
6d5786a3	604	free_xid(xid);
1da177e4 LT	605	return rc;
1da177e4 LT	606	}