[deliverable/linux.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,
		 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;
}

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, cifs_sb, full_path,
				      &target_path);

	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,
8205d1bb SP	240	struct cifs_sb_info cifs_sb, const unsigned char path,
8205d1bb SP	241	char **symlinkinfo)
0fd43ae4 SM	242	{
0fd43ae4 SM	243	int rc;
8205d1bb	244	u8 *buf = NULL;
0fd43ae4	245	unsigned int link_len = 0;
8205d1bb	246	unsigned int bytes_read = 0;
0fd43ae4 SM	247
	248	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
	249	if (!buf)
	250	return -ENOMEM;
0fd43ae4	251
8205d1bb SP	252	if (tcon->ses->server->ops->query_mf_symlink)
	253	rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
	254	cifs_sb, path, buf, &bytes_read);
	255	else
	256	rc = -ENOSYS;
	257
	258	if (rc)
	259	goto out;
	260
	261	if (bytes_read == 0) { /* not a symlink */
	262	rc = -EINVAL;
	263	goto out;
0fd43ae4 SM	264	}
0fd43ae4 SM	265
cb084b1a	266	rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
8205d1bb	267	out:
0fd43ae4	268	kfree(buf);
8205d1bb	269	return rc;
0fd43ae4 SM	270	}
0fd43ae4 SM	271
8bfb50a8	272	bool
cb084b1a	273	couldbe_mf_symlink(const struct cifs_fattr *fattr)
8bfb50a8 SM	274	{
	275	if (!(fattr->cf_mode & S_IFREG))
	276	/* it's not a symlink */
	277	return false;
	278
	279	if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
	280	/* it's not a symlink */
	281	return false;
	282
	283	return true;
	284	}
	285
	286	int
b5be1a1c SP	287	cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
	288	struct cifs_sb_info cifs_sb, const unsigned char path,
	289	char pbuf, unsigned int pbytes_read)
8bfb50a8 SM	290	{
	291	int rc;
	292	int oplock = 0;
	293	__u16 netfid = 0;
d4ffff1f	294	struct cifs_io_parms io_parms;
8bfb50a8	295	int buf_type = CIFS_NO_BUFFER;
8bfb50a8 SM	296	FILE_ALL_INFO file_info;
8bfb50a8 SM	297
b5be1a1c	298	rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, GENERIC_READ,
8bfb50a8 SM	299	CREATE_NOT_DIR, &netfid, &oplock, &file_info,
	300	cifs_sb->local_nls,
	301	cifs_sb->mnt_cifs_flags &
	302	CIFS_MOUNT_MAP_SPECIAL_CHR);
b5be1a1c	303	if (rc)
1b244081	304	return rc;
8bfb50a8	305
b5be1a1c	306	if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE))
8bfb50a8	307	/* it's not a symlink */
b5be1a1c	308	goto out;
8bfb50a8	309
d4ffff1f PS	310	io_parms.netfid = netfid;
d4ffff1f PS	311	io_parms.pid = current->tgid;
b5be1a1c	312	io_parms.tcon = tcon;
d4ffff1f PS	313	io_parms.offset = 0;
d4ffff1f PS	314	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
8bfb50a8	315
1b244081	316	rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
b5be1a1c SP	317	out:
b5be1a1c SP	318	CIFSSMBClose(xid, tcon, netfid);
1b244081 SF	319	return rc;
	320	}
	321
1b244081	322	int
cb084b1a SP	323	check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
	324	struct cifs_sb_info cifs_sb, struct cifs_fattr fattr,
	325	const unsigned char *path)
1b244081	326	{
750b8de6	327	int rc;
1b244081 SF	328	u8 *buf = NULL;
	329	unsigned int link_len = 0;
	330	unsigned int bytes_read = 0;
1b244081	331
cb084b1a	332	if (!couldbe_mf_symlink(fattr))
1b244081 SF	333	/* it's not a symlink */
	334	return 0;
	335
	336	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
750b8de6 SP	337	if (!buf)
750b8de6 SP	338	return -ENOMEM;
8bfb50a8	339
750b8de6	340	if (tcon->ses->server->ops->query_mf_symlink)
b5be1a1c SP	341	rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
b5be1a1c SP	342	cifs_sb, path, buf, &bytes_read);
1b244081	343	else
750b8de6	344	rc = -ENOSYS;
1b244081	345
750b8de6	346	if (rc)
1b244081 SF	347	goto out;
	348
	349	if (bytes_read == 0) /* not a symlink */
	350	goto out;
	351
cb084b1a	352	rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
7ffec372	353	if (rc == -EINVAL) {
8bfb50a8	354	/* it's not a symlink */
7ffec372 JL	355	rc = 0;
	356	goto out;
	357	}
	358
8bfb50a8	359	if (rc != 0)
7ffec372	360	goto out;
8bfb50a8 SM	361
	362	/* it is a symlink */
	363	fattr->cf_eof = link_len;
	364	fattr->cf_mode &= ~S_IFMT;
	365	fattr->cf_mode \|= S_IFLNK \| S_IRWXU \| S_IRWXG \| S_IRWXO;
	366	fattr->cf_dtype = DT_LNK;
7ffec372	367	out:
1b244081	368	kfree(buf);
7ffec372	369	return rc;
8bfb50a8 SM	370	}
8bfb50a8 SM	371
1da177e4 LT	372	int
	373	cifs_hardlink(struct dentry old_file, struct inode inode,
	374	struct dentry *direntry)
	375	{
	376	int rc = -EACCES;
6d5786a3	377	unsigned int xid;
d6e906f1 SF	378	char *from_name = NULL;
d6e906f1 SF	379	char *to_name = NULL;
7ffec372 JL	380	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
7ffec372 JL	381	struct tcon_link *tlink;
d6e906f1 SF	382	struct cifs_tcon *tcon;
d6e906f1 SF	383	struct TCP_Server_Info *server;
1da177e4 LT	384	struct cifsInodeInfo *cifsInode;
1da177e4 LT	385
7ffec372 JL	386	tlink = cifs_sb_tlink(cifs_sb);
	387	if (IS_ERR(tlink))
	388	return PTR_ERR(tlink);
d6e906f1	389	tcon = tlink_tcon(tlink);
1da177e4	390
6d5786a3	391	xid = get_xid();
1da177e4	392
d6e906f1 SF	393	from_name = build_path_from_dentry(old_file);
	394	to_name = build_path_from_dentry(direntry);
	395	if ((from_name == NULL) \|\| (to_name == NULL)) {
1da177e4 LT	396	rc = -ENOMEM;
	397	goto cifs_hl_exit;
	398	}
	399
d6e906f1 SF	400	if (tcon->unix_ext)
d6e906f1 SF	401	rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
7ffec372 JL	402	cifs_sb->local_nls,
7ffec372 JL	403	cifs_sb->mnt_cifs_flags &
737b758c	404	CIFS_MOUNT_MAP_SPECIAL_CHR);
1da177e4	405	else {
d6e906f1	406	server = tcon->ses->server;
abf9767c CE	407	if (!server->ops->create_hardlink) {
	408	rc = -ENOSYS;
	409	goto cifs_hl_exit;
	410	}
d6e906f1 SF	411	rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
d6e906f1 SF	412	cifs_sb);
fb8c4b14 SF	413	if ((rc == -EIO) \|\| (rc == -EINVAL))
fb8c4b14 SF	414	rc = -EOPNOTSUPP;
1da177e4 LT	415	}
1da177e4 LT	416
31ec35d6 SF	417	d_drop(direntry); /* force new lookup from server of target */
31ec35d6 SF	418
d6e906f1 SF	419	/*
	420	* if source file is cached (oplocked) revalidate will not go to server
	421	* until the file is closed or oplock broken so update nlinks locally
	422	*/
fb8c4b14	423	if (old_file->d_inode) {
31ec35d6	424	cifsInode = CIFS_I(old_file->d_inode);
fb8c4b14	425	if (rc == 0) {
b7ca6928	426	spin_lock(&old_file->d_inode->i_lock);
6d6b77f1	427	inc_nlink(old_file->d_inode);
b7ca6928	428	spin_unlock(&old_file->d_inode->i_lock);
d6e906f1 SF	429	/*
	430	* BB should we make this contingent on superblock flag
	431	* NOATIME?
	432	*/
	433	/* old_file->d_inode->i_ctime = CURRENT_TIME; */
	434	/*
	435	* parent dir timestamps will update from srv within a
	436	* second, would it really be worth it to set the parent
	437	* dir cifs inode time to zero to force revalidate
	438	* (faster) for it too?
	439	*/
31ec35d6	440	}
d6e906f1 SF	441	/*
	442	* if not oplocked will force revalidate to get info on source
	443	* file from srv
	444	*/
31ec35d6 SF	445	cifsInode->time = 0;
31ec35d6 SF	446
d6e906f1 SF	447	/*
	448	* Will update parent dir timestamps from srv within a second.
	449	* Would it really be worth it to set the parent dir (cifs
	450	* inode) time field to zero to force revalidate on parent
	451	* directory faster ie
	452	*
	453	* CIFS_I(inode)->time = 0;
	454	*/
1da177e4	455	}
1da177e4 LT	456
1da177e4 LT	457	cifs_hl_exit:
d6e906f1 SF	458	kfree(from_name);
d6e906f1 SF	459	kfree(to_name);
6d5786a3	460	free_xid(xid);
7ffec372	461	cifs_put_tlink(tlink);
1da177e4 LT	462	return rc;
	463	}
	464
cc314eef	465	void *
1da177e4 LT	466	cifs_follow_link(struct dentry direntry, struct nameidata nd)
	467	{
	468	struct inode *inode = direntry->d_inode;
8b6427a2	469	int rc = -ENOMEM;
6d5786a3	470	unsigned int xid;
1da177e4	471	char *full_path = NULL;
8b6427a2 JL	472	char *target_path = NULL;
8b6427a2 JL	473	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
7ffec372	474	struct tcon_link *tlink = NULL;
96daf2b0	475	struct cifs_tcon *tcon;
b42bf888	476	struct TCP_Server_Info *server;
1da177e4	477
6d5786a3	478	xid = get_xid();
1da177e4	479
7ffec372 JL	480	tlink = cifs_sb_tlink(cifs_sb);
	481	if (IS_ERR(tlink)) {
	482	rc = PTR_ERR(tlink);
	483	tlink = NULL;
	484	goto out;
	485	}
	486	tcon = tlink_tcon(tlink);
b42bf888	487	server = tcon->ses->server;
1da177e4	488
8b6427a2	489	full_path = build_path_from_dentry(direntry);
1da177e4	490	if (!full_path)
460b9696	491	goto out;
1da177e4	492
f96637be	493	cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
1da177e4	494
1b12b9c1 SM	495	rc = -EACCES;
	496	/*
	497	* First try Minshall+French Symlinks, if configured
	498	* and fallback to UNIX Extensions Symlinks.
	499	*/
	500	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
8205d1bb SP	501	rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
8205d1bb SP	502	&target_path);
1b12b9c1	503
29e20f9c	504	if ((rc != 0) && cap_unix(tcon->ses))
1b12b9c1 SM	505	rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
1b12b9c1 SM	506	cifs_sb->local_nls);
b42bf888 PS	507	else if (rc != 0 && server->ops->query_symlink)
	508	rc = server->ops->query_symlink(xid, tcon, full_path,
	509	&target_path, cifs_sb);
1b12b9c1	510
8b6427a2 JL	511	kfree(full_path);
8b6427a2 JL	512	out:
460b9696	513	if (rc != 0) {
1da177e4 LT	514	kfree(target_path);
	515	target_path = ERR_PTR(rc);
	516	}
	517
6d5786a3	518	free_xid(xid);
7ffec372 JL	519	if (tlink)
7ffec372 JL	520	cifs_put_tlink(tlink);
1da177e4	521	nd_set_link(nd, target_path);
460b9696	522	return NULL;
1da177e4 LT	523	}
	524
	525	int
	526	cifs_symlink(struct inode inode, struct dentry direntry, const char *symname)
	527	{
	528	int rc = -EOPNOTSUPP;
6d5786a3	529	unsigned int xid;
7ffec372 JL	530	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
7ffec372 JL	531	struct tcon_link *tlink;
96daf2b0	532	struct cifs_tcon *pTcon;
1da177e4 LT	533	char *full_path = NULL;
	534	struct inode *newinode = NULL;
	535
6d5786a3	536	xid = get_xid();
1da177e4	537
7ffec372 JL	538	tlink = cifs_sb_tlink(cifs_sb);
	539	if (IS_ERR(tlink)) {
	540	rc = PTR_ERR(tlink);
	541	goto symlink_exit;
	542	}
	543	pTcon = tlink_tcon(tlink);
1da177e4	544
7f57356b	545	full_path = build_path_from_dentry(direntry);
fb8c4b14	546	if (full_path == NULL) {
0f3bc09e	547	rc = -ENOMEM;
7ffec372	548	goto symlink_exit;
1da177e4 LT	549	}
1da177e4 LT	550
f96637be JP	551	cifs_dbg(FYI, "Full path: %s\n", full_path);
f96637be JP	552	cifs_dbg(FYI, "symname is %s\n", symname);
1da177e4 LT	553
1da177e4 LT	554	/* BB what if DFS and this volume is on different share? BB */
1b12b9c1	555	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
cb084b1a	556	rc = create_mf_symlink(xid, pTcon, full_path, symname,
3d3ea8e6	557	cifs_sb);
1b12b9c1	558	else if (pTcon->unix_ext)
1da177e4 LT	559	rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
	560	cifs_sb->local_nls);
	561	/* else
fb8c4b14 SF	562	rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
fb8c4b14 SF	563	cifs_sb_target->local_nls); */
1da177e4 LT	564
1da177e4 LT	565	if (rc == 0) {
c18c842b	566	if (pTcon->unix_ext)
1da177e4	567	rc = cifs_get_inode_info_unix(&newinode, full_path,
fb8c4b14	568	inode->i_sb, xid);
1da177e4 LT	569	else
1da177e4 LT	570	rc = cifs_get_inode_info(&newinode, full_path, NULL,
8b1327f6	571	inode->i_sb, xid, NULL);
1da177e4 LT	572
1da177e4 LT	573	if (rc != 0) {
f96637be JP	574	cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
f96637be JP	575	rc);
1da177e4	576	} else {
1da177e4 LT	577	d_instantiate(direntry, newinode);
	578	}
	579	}
7ffec372	580	symlink_exit:
f99d49ad	581	kfree(full_path);
7ffec372	582	cifs_put_tlink(tlink);
6d5786a3	583	free_xid(xid);
1da177e4 LT	584	return rc;
1da177e4 LT	585	}