[linux-block.git] / fs / cifs / cifs_unicode.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 *   Copyright (c) International Business Machines  Corp., 2000,2009
 *   Modified by Steve French (sfrench@us.ibm.com)
 */
#include <linux/fs.h>
#include <linux/slab.h>
#include "cifs_fs_sb.h"
#include "cifs_unicode.h"
#include "cifs_uniupr.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifs_debug.h"

int cifs_remap(struct cifs_sb_info *cifs_sb)
{
	int map_type;

	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)
		map_type = SFM_MAP_UNI_RSVD;
	else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
		map_type = SFU_MAP_UNI_RSVD;
	else
		map_type = NO_MAP_UNI_RSVD;

	return map_type;
}

/* Convert character using the SFU - "Services for Unix" remapping range */
static bool
convert_sfu_char(const __u16 src_char, char *target)
{
	/*
	 * BB: Cannot handle remapping UNI_SLASH until all the calls to
	 *     build_path_from_dentry are modified, as they use slash as
	 *     separator.
	 */
	switch (src_char) {
	case UNI_COLON:
		*target = ':';
		break;
	case UNI_ASTERISK:
		*target = '*';
		break;
	case UNI_QUESTION:
		*target = '?';
		break;
	case UNI_PIPE:
		*target = '|';
		break;
	case UNI_GRTRTHAN:
		*target = '>';
		break;
	case UNI_LESSTHAN:
		*target = '<';
		break;
	default:
		return false;
	}
	return true;
}

/* Convert character using the SFM - "Services for Mac" remapping range */
static bool
convert_sfm_char(const __u16 src_char, char *target)
{
	if (src_char >= 0xF001 && src_char <= 0xF01F) {
		*target = src_char - 0xF000;
		return true;
	}
	switch (src_char) {
	case SFM_COLON:
		*target = ':';
		break;
	case SFM_DOUBLEQUOTE:
		*target = '"';
		break;
	case SFM_ASTERISK:
		*target = '*';
		break;
	case SFM_QUESTION:
		*target = '?';
		break;
	case SFM_PIPE:
		*target = '|';
		break;
	case SFM_GRTRTHAN:
		*target = '>';
		break;
	case SFM_LESSTHAN:
		*target = '<';
		break;
	case SFM_SPACE:
		*target = ' ';
		break;
	case SFM_PERIOD:
		*target = '.';
		break;
	default:
		return false;
	}
	return true;
}


/*
 * cifs_mapchar - convert a host-endian char to proper char in codepage
 * @target - where converted character should be copied
 * @src_char - 2 byte host-endian source character
 * @cp - codepage to which character should be converted
 * @map_type - How should the 7 NTFS/SMB reserved characters be mapped to UCS2?
 *
 * This function handles the conversion of a single character. It is the
 * responsibility of the caller to ensure that the target buffer is large
 * enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
 */
static int
cifs_mapchar(char *target, const __u16 *from, const struct nls_table *cp,
	     int maptype)
{
	int len = 1;
	__u16 src_char;

	src_char = *from;

	if ((maptype == SFM_MAP_UNI_RSVD) && convert_sfm_char(src_char, target))
		return len;
	else if ((maptype == SFU_MAP_UNI_RSVD) &&
		  convert_sfu_char(src_char, target))
		return len;

	/* if character not one of seven in special remap set */
	len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);
	if (len <= 0)
		goto surrogate_pair;

	return len;

surrogate_pair:
	/* convert SURROGATE_PAIR and IVS */
	if (strcmp(cp->charset, "utf8"))
		goto unknown;
	len = utf16s_to_utf8s(from, 3, UTF16_LITTLE_ENDIAN, target, 6);
	if (len <= 0)
		goto unknown;
	return len;

unknown:
	*target = '?';
	len = 1;
	return len;
}

/*
 * cifs_from_utf16 - convert utf16le string to local charset
 * @to - destination buffer
 * @from - source buffer
 * @tolen - destination buffer size (in bytes)
 * @fromlen - source buffer size (in bytes)
 * @codepage - codepage to which characters should be converted
 * @mapchar - should characters be remapped according to the mapchars option?
 *
 * Convert a little-endian utf16le string (as sent by the server) to a string
 * in the provided codepage. The tolen and fromlen parameters are to ensure
 * that the code doesn't walk off of the end of the buffer (which is always
 * a danger if the alignment of the source buffer is off). The destination
 * string is always properly null terminated and fits in the destination
 * buffer. Returns the length of the destination string in bytes (including
 * null terminator).
 *
 * Note that some windows versions actually send multiword UTF-16 characters
 * instead of straight UTF16-2. The linux nls routines however aren't able to
 * deal with those characters properly. In the event that we get some of
 * those characters, they won't be translated properly.
 */
int
cifs_from_utf16(char *to, const __le16 *from, int tolen, int fromlen,
		const struct nls_table *codepage, int map_type)
{
	int i, charlen, safelen;
	int outlen = 0;
	int nullsize = nls_nullsize(codepage);
	int fromwords = fromlen / 2;
	char tmp[NLS_MAX_CHARSET_SIZE];
	__u16 ftmp[3];		/* ftmp[3] = 3array x 2bytes = 6bytes UTF-16 */

	/*
	 * because the chars can be of varying widths, we need to take care
	 * not to overflow the destination buffer when we get close to the
	 * end of it. Until we get to this offset, we don't need to check
	 * for overflow however.
	 */
	safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);

	for (i = 0; i < fromwords; i++) {
		ftmp[0] = get_unaligned_le16(&from[i]);
		if (ftmp[0] == 0)
			break;
		if (i + 1 < fromwords)
			ftmp[1] = get_unaligned_le16(&from[i + 1]);
		else
			ftmp[1] = 0;
		if (i + 2 < fromwords)
			ftmp[2] = get_unaligned_le16(&from[i + 2]);
		else
			ftmp[2] = 0;

		/*
		 * check to see if converting this character might make the
		 * conversion bleed into the null terminator
		 */
		if (outlen >= safelen) {
			charlen = cifs_mapchar(tmp, ftmp, codepage, map_type);
			if ((outlen + charlen) > (tolen - nullsize))
				break;
		}

		/* put converted char into 'to' buffer */
		charlen = cifs_mapchar(&to[outlen], ftmp, codepage, map_type);
		outlen += charlen;

		/* charlen (=bytes of UTF-8 for 1 character)
		 * 4bytes UTF-8(surrogate pair) is charlen=4
		 *   (4bytes UTF-16 code)
		 * 7-8bytes UTF-8(IVS) is charlen=3+4 or 4+4
		 *   (2 UTF-8 pairs divided to 2 UTF-16 pairs) */
		if (charlen == 4)
			i++;
		else if (charlen >= 5)
			/* 5-6bytes UTF-8 */
			i += 2;
	}

	/* properly null-terminate string */
	for (i = 0; i < nullsize; i++)
		to[outlen++] = 0;

	return outlen;
}

/*
 * NAME:	cifs_strtoUTF16()
 *
 * FUNCTION:	Convert character string to unicode string
 *
 */
int
cifs_strtoUTF16(__le16 *to, const char *from, int len,
	      const struct nls_table *codepage)
{
	int charlen;
	int i;
	wchar_t wchar_to; /* needed to quiet sparse */

	/* special case for utf8 to handle no plane0 chars */
	if (!strcmp(codepage->charset, "utf8")) {
		/*
		 * convert utf8 -> utf16, we assume we have enough space
		 * as caller should have assumed conversion does not overflow
		 * in destination len is length in wchar_t units (16bits)
		 */
		i  = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,
				       (wchar_t *) to, len);

		/* if success terminate and exit */
		if (i >= 0)
			goto success;
		/*
		 * if fails fall back to UCS encoding as this
		 * function should not return negative values
		 * currently can fail only if source contains
		 * invalid encoded characters
		 */
	}

	for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
		charlen = codepage->char2uni(from, len, &wchar_to);
		if (charlen < 1) {
			cifs_dbg(VFS, "strtoUTF16: char2uni of 0x%x returned %d\n",
				 *from, charlen);
			/* A question mark */
			wchar_to = 0x003f;
			charlen = 1;
		}
		put_unaligned_le16(wchar_to, &to[i]);
	}

success:
	put_unaligned_le16(0, &to[i]);
	return i;
}

/*
 * cifs_utf16_bytes - how long will a string be after conversion?
 * @utf16 - pointer to input string
 * @maxbytes - don't go past this many bytes of input string
 * @codepage - destination codepage
 *
 * Walk a utf16le string and return the number of bytes that the string will
 * be after being converted to the given charset, not including any null
 * termination required. Don't walk past maxbytes in the source buffer.
 */
int
cifs_utf16_bytes(const __le16 *from, int maxbytes,
		const struct nls_table *codepage)
{
	int i;
	int charlen, outlen = 0;
	int maxwords = maxbytes / 2;
	char tmp[NLS_MAX_CHARSET_SIZE];
	__u16 ftmp[3];

	for (i = 0; i < maxwords; i++) {
		ftmp[0] = get_unaligned_le16(&from[i]);
		if (ftmp[0] == 0)
			break;
		if (i + 1 < maxwords)
			ftmp[1] = get_unaligned_le16(&from[i + 1]);
		else
			ftmp[1] = 0;
		if (i + 2 < maxwords)
			ftmp[2] = get_unaligned_le16(&from[i + 2]);
		else
			ftmp[2] = 0;

		charlen = cifs_mapchar(tmp, ftmp, codepage, NO_MAP_UNI_RSVD);
		outlen += charlen;
	}

	return outlen;
}

/*
 * cifs_strndup_from_utf16 - copy a string from wire format to the local
 * codepage
 * @src - source string
 * @maxlen - don't walk past this many bytes in the source string
 * @is_unicode - is this a unicode string?
 * @codepage - destination codepage
 *
 * Take a string given by the server, convert it to the local codepage and
 * put it in a new buffer. Returns a pointer to the new string or NULL on
 * error.
 */
char *
cifs_strndup_from_utf16(const char *src, const int maxlen,
			const bool is_unicode, const struct nls_table *codepage)
{
	int len;
	char *dst;

	if (is_unicode) {
		len = cifs_utf16_bytes((__le16 *) src, maxlen, codepage);
		len += nls_nullsize(codepage);
		dst = kmalloc(len, GFP_KERNEL);
		if (!dst)
			return NULL;
		cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage,
				NO_MAP_UNI_RSVD);
	} else {
		dst = kstrndup(src, maxlen, GFP_KERNEL);
	}

	return dst;
}

static __le16 convert_to_sfu_char(char src_char)
{
	__le16 dest_char;

	switch (src_char) {
	case ':':
		dest_char = cpu_to_le16(UNI_COLON);
		break;
	case '*':
		dest_char = cpu_to_le16(UNI_ASTERISK);
		break;
	case '?':
		dest_char = cpu_to_le16(UNI_QUESTION);
		break;
	case '<':
		dest_char = cpu_to_le16(UNI_LESSTHAN);
		break;
	case '>':
		dest_char = cpu_to_le16(UNI_GRTRTHAN);
		break;
	case '|':
		dest_char = cpu_to_le16(UNI_PIPE);
		break;
	default:
		dest_char = 0;
	}

	return dest_char;
}

static __le16 convert_to_sfm_char(char src_char, bool end_of_string)
{
	__le16 dest_char;

	if (src_char >= 0x01 && src_char <= 0x1F) {
		dest_char = cpu_to_le16(src_char + 0xF000);
		return dest_char;
	}
	switch (src_char) {
	case ':':
		dest_char = cpu_to_le16(SFM_COLON);
		break;
	case '"':
		dest_char = cpu_to_le16(SFM_DOUBLEQUOTE);
		break;
	case '*':
		dest_char = cpu_to_le16(SFM_ASTERISK);
		break;
	case '?':
		dest_char = cpu_to_le16(SFM_QUESTION);
		break;
	case '<':
		dest_char = cpu_to_le16(SFM_LESSTHAN);
		break;
	case '>':
		dest_char = cpu_to_le16(SFM_GRTRTHAN);
		break;
	case '|':
		dest_char = cpu_to_le16(SFM_PIPE);
		break;
	case '.':
		if (end_of_string)
			dest_char = cpu_to_le16(SFM_PERIOD);
		else
			dest_char = 0;
		break;
	case ' ':
		if (end_of_string)
			dest_char = cpu_to_le16(SFM_SPACE);
		else
			dest_char = 0;
		break;
	default:
		dest_char = 0;
	}

	return dest_char;
}

/*
 * Convert 16 bit Unicode pathname to wire format from string in current code
 * page. Conversion may involve remapping up the six characters that are
 * only legal in POSIX-like OS (if they are present in the string). Path
 * names are little endian 16 bit Unicode on the wire
 */
int
cifsConvertToUTF16(__le16 *target, const char *source, int srclen,
		 const struct nls_table *cp, int map_chars)
{
	int i, charlen;
	int j = 0;
	char src_char;
	__le16 dst_char;
	wchar_t tmp;
	wchar_t *wchar_to;	/* UTF-16 */
	int ret;
	unicode_t u;

	if (map_chars == NO_MAP_UNI_RSVD)
		return cifs_strtoUTF16(target, source, PATH_MAX, cp);

	wchar_to = kzalloc(6, GFP_KERNEL);

	for (i = 0; i < srclen; j++) {
		src_char = source[i];
		charlen = 1;

		/* check if end of string */
		if (src_char == 0)
			goto ctoUTF16_out;

		/* see if we must remap this char */
		if (map_chars == SFU_MAP_UNI_RSVD)
			dst_char = convert_to_sfu_char(src_char);
		else if (map_chars == SFM_MAP_UNI_RSVD) {
			bool end_of_string;

			/**
			 * Remap spaces and periods found at the end of every
			 * component of the path. The special cases of '.' and
			 * '..' do not need to be dealt with explicitly because
			 * they are addressed in namei.c:link_path_walk().
			 **/
			if ((i == srclen - 1) || (source[i+1] == '\\'))
				end_of_string = true;
			else
				end_of_string = false;

			dst_char = convert_to_sfm_char(src_char, end_of_string);
		} else
			dst_char = 0;
		/*
		 * FIXME: We can not handle remapping backslash (UNI_SLASH)
		 * until all the calls to build_path_from_dentry are modified,
		 * as they use backslash as separator.
		 */
		if (dst_char == 0) {
			charlen = cp->char2uni(source + i, srclen - i, &tmp);
			dst_char = cpu_to_le16(tmp);

			/*
			 * if no match, use question mark, which at least in
			 * some cases serves as wild card
			 */
			if (charlen > 0)
				goto ctoUTF16;

			/* convert SURROGATE_PAIR */
			if (strcmp(cp->charset, "utf8") || !wchar_to)
				goto unknown;
			if (*(source + i) & 0x80) {
				charlen = utf8_to_utf32(source + i, 6, &u);
				if (charlen < 0)
					goto unknown;
			} else
				goto unknown;
			ret  = utf8s_to_utf16s(source + i, charlen,
					       UTF16_LITTLE_ENDIAN,
					       wchar_to, 6);
			if (ret < 0)
				goto unknown;

			i += charlen;
			dst_char = cpu_to_le16(*wchar_to);
			if (charlen <= 3)
				/* 1-3bytes UTF-8 to 2bytes UTF-16 */
				put_unaligned(dst_char, &target[j]);
			else if (charlen == 4) {
				/* 4bytes UTF-8(surrogate pair) to 4bytes UTF-16
				 * 7-8bytes UTF-8(IVS) divided to 2 UTF-16
				 *   (charlen=3+4 or 4+4) */
				put_unaligned(dst_char, &target[j]);
				dst_char = cpu_to_le16(*(wchar_to + 1));
				j++;
				put_unaligned(dst_char, &target[j]);
			} else if (charlen >= 5) {
				/* 5-6bytes UTF-8 to 6bytes UTF-16 */
				put_unaligned(dst_char, &target[j]);
				dst_char = cpu_to_le16(*(wchar_to + 1));
				j++;
				put_unaligned(dst_char, &target[j]);
				dst_char = cpu_to_le16(*(wchar_to + 2));
				j++;
				put_unaligned(dst_char, &target[j]);
			}
			continue;

unknown:
			dst_char = cpu_to_le16(0x003f);
			charlen = 1;
		}

ctoUTF16:
		/*
		 * character may take more than one byte in the source string,
		 * but will take exactly two bytes in the target string
		 */
		i += charlen;
		put_unaligned(dst_char, &target[j]);
	}

ctoUTF16_out:
	put_unaligned(0, &target[j]); /* Null terminate target unicode string */
	kfree(wchar_to);
	return j;
}

/*
 * cifs_local_to_utf16_bytes - how long will a string be after conversion?
 * @from - pointer to input string
 * @maxbytes - don't go past this many bytes of input string
 * @codepage - source codepage
 *
 * Walk a string and return the number of bytes that the string will
 * be after being converted to the given charset, not including any null
 * termination required. Don't walk past maxbytes in the source buffer.
 */

static int
cifs_local_to_utf16_bytes(const char *from, int len,
			  const struct nls_table *codepage)
{
	int charlen;
	int i;
	wchar_t wchar_to;

	for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
		charlen = codepage->char2uni(from, len, &wchar_to);
		/* Failed conversion defaults to a question mark */
		if (charlen < 1)
			charlen = 1;
	}
	return 2 * i; /* UTF16 characters are two bytes */
}

/*
 * cifs_strndup_to_utf16 - copy a string to wire format from the local codepage
 * @src - source string
 * @maxlen - don't walk past this many bytes in the source string
 * @utf16_len - the length of the allocated string in bytes (including null)
 * @cp - source codepage
 * @remap - map special chars
 *
 * Take a string convert it from the local codepage to UTF16 and
 * put it in a new buffer. Returns a pointer to the new string or NULL on
 * error.
 */
__le16 *
cifs_strndup_to_utf16(const char *src, const int maxlen, int *utf16_len,
		      const struct nls_table *cp, int remap)
{
	int len;
	__le16 *dst;

	len = cifs_local_to_utf16_bytes(src, maxlen, cp);
	len += 2; /* NULL */
	dst = kmalloc(len, GFP_KERNEL);
	if (!dst) {
		*utf16_len = 0;
		return NULL;
	}
	cifsConvertToUTF16(dst, src, strlen(src), cp, remap);
	*utf16_len = len;
	return dst;
}
Commit	Line	Data
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4	2	/*
1da177e4	3	*
d185cda7	4	* Copyright (c) International Business Machines Corp., 2000,2009
1da177e4	5	* Modified by Steve French (sfrench@us.ibm.com)
1da177e4 LT	6	*/
1da177e4 LT	7	#include <linux/fs.h>
5a0e3ad6	8	#include <linux/slab.h>
2baa2682	9	#include "cifs_fs_sb.h"
1da177e4 LT	10	#include "cifs_unicode.h"
	11	#include "cifs_uniupr.h"
	12	#include "cifspdu.h"
3979877e	13	#include "cifsglob.h"
1da177e4 LT	14	#include "cifs_debug.h"
1da177e4 LT	15
2baa2682 SF	16	int cifs_remap(struct cifs_sb_info *cifs_sb)
	17	{
	18	int map_type;
	19
	20	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)
	21	map_type = SFM_MAP_UNI_RSVD;
	22	else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
	23	map_type = SFU_MAP_UNI_RSVD;
	24	else
	25	map_type = NO_MAP_UNI_RSVD;
	26
	27	return map_type;
	28	}
	29
b693855f SF	30	/* Convert character using the SFU - "Services for Unix" remapping range */
	31	static bool
	32	convert_sfu_char(const __u16 src_char, char *target)
7fabf0c9	33	{
7fabf0c9 JL	34	/*
	35	* BB: Cannot handle remapping UNI_SLASH until all the calls to
	36	* build_path_from_dentry are modified, as they use slash as
	37	* separator.
	38	*/
ba2dbf30	39	switch (src_char) {
7fabf0c9 JL	40	case UNI_COLON:
	41	*target = ':';
	42	break;
581ade4d	43	case UNI_ASTERISK:
7fabf0c9 JL	44	target = '';
	45	break;
	46	case UNI_QUESTION:
	47	*target = '?';
	48	break;
	49	case UNI_PIPE:
	50	*target = '\|';
	51	break;
	52	case UNI_GRTRTHAN:
	53	*target = '>';
	54	break;
	55	case UNI_LESSTHAN:
	56	*target = '<';
	57	break;
	58	default:
b693855f	59	return false;
7fabf0c9	60	}
b693855f SF	61	return true;
b693855f SF	62	}
7fabf0c9	63
b693855f SF	64	/* Convert character using the SFM - "Services for Mac" remapping range */
	65	static bool
	66	convert_sfm_char(const __u16 src_char, char *target)
	67	{
7e46f090 BJ	68	if (src_char >= 0xF001 && src_char <= 0xF01F) {
	69	*target = src_char - 0xF000;
	70	return true;
	71	}
b693855f SF	72	switch (src_char) {
	73	case SFM_COLON:
	74	*target = ':';
	75	break;
85435d7a BJ	76	case SFM_DOUBLEQUOTE:
	77	*target = '"';
	78	break;
b693855f SF	79	case SFM_ASTERISK:
	80	target = '';
	81	break;
	82	case SFM_QUESTION:
	83	*target = '?';
	84	break;
	85	case SFM_PIPE:
	86	*target = '\|';
	87	break;
	88	case SFM_GRTRTHAN:
	89	*target = '>';
	90	break;
	91	case SFM_LESSTHAN:
	92	*target = '<';
	93	break;
45e8a258 SF	94	case SFM_SPACE:
	95	*target = ' ';
	96	break;
	97	case SFM_PERIOD:
	98	*target = '.';
	99	break;
b693855f SF	100	default:
	101	return false;
	102	}
	103	return true;
	104	}
	105
	106
	107	/*
	108	* cifs_mapchar - convert a host-endian char to proper char in codepage
	109	* @target - where converted character should be copied
	110	* @src_char - 2 byte host-endian source character
	111	* @cp - codepage to which character should be converted
	112	* @map_type - How should the 7 NTFS/SMB reserved characters be mapped to UCS2?
	113	*
	114	* This function handles the conversion of a single character. It is the
	115	* responsibility of the caller to ensure that the target buffer is large
	116	* enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
	117	*/
	118	static int
b2910307	119	cifs_mapchar(char target, const __u16 from, const struct nls_table *cp,
b693855f SF	120	int maptype)
	121	{
	122	int len = 1;
b2910307 NA	123	__u16 src_char;
	124
	125	src_char = *from;
b693855f SF	126
	127	if ((maptype == SFM_MAP_UNI_RSVD) && convert_sfm_char(src_char, target))
	128	return len;
	129	else if ((maptype == SFU_MAP_UNI_RSVD) &&
	130	convert_sfu_char(src_char, target))
	131	return len;
7fabf0c9	132
b693855f	133	/* if character not one of seven in special remap set */
ba2dbf30	134	len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);
b2910307 NA	135	if (len <= 0)
	136	goto surrogate_pair;
	137
	138	return len;
	139
	140	surrogate_pair:
	141	/* convert SURROGATE_PAIR and IVS */
	142	if (strcmp(cp->charset, "utf8"))
	143	goto unknown;
	144	len = utf16s_to_utf8s(from, 3, UTF16_LITTLE_ENDIAN, target, 6);
	145	if (len <= 0)
	146	goto unknown;
	147	return len;
	148
	149	unknown:
	150	*target = '?';
	151	len = 1;
b693855f	152	return len;
7fabf0c9 JL	153	}
	154
	155	/*
acbbb76a	156	* cifs_from_utf16 - convert utf16le string to local charset
7fabf0c9 JL	157	* @to - destination buffer
	158	* @from - source buffer
	159	* @tolen - destination buffer size (in bytes)
	160	* @fromlen - source buffer size (in bytes)
	161	* @codepage - codepage to which characters should be converted
	162	* @mapchar - should characters be remapped according to the mapchars option?
	163	*
acbbb76a	164	* Convert a little-endian utf16le string (as sent by the server) to a string
7fabf0c9 JL	165	* in the provided codepage. The tolen and fromlen parameters are to ensure
	166	* that the code doesn't walk off of the end of the buffer (which is always
	167	* a danger if the alignment of the source buffer is off). The destination
	168	* string is always properly null terminated and fits in the destination
	169	* buffer. Returns the length of the destination string in bytes (including
	170	* null terminator).
	171	*
	172	* Note that some windows versions actually send multiword UTF-16 characters
acbbb76a	173	* instead of straight UTF16-2. The linux nls routines however aren't able to
7fabf0c9 JL	174	* deal with those characters properly. In the event that we get some of
	175	* those characters, they won't be translated properly.
	176	*/
	177	int
acbbb76a	178	cifs_from_utf16(char to, const __le16 from, int tolen, int fromlen,
b693855f	179	const struct nls_table *codepage, int map_type)
7fabf0c9 JL	180	{
	181	int i, charlen, safelen;
	182	int outlen = 0;
	183	int nullsize = nls_nullsize(codepage);
	184	int fromwords = fromlen / 2;
	185	char tmp[NLS_MAX_CHARSET_SIZE];
b2910307	186	__u16 ftmp[3]; /* ftmp[3] = 3array x 2bytes = 6bytes UTF-16 */
7fabf0c9 JL	187
	188	/*
	189	* because the chars can be of varying widths, we need to take care
	190	* not to overflow the destination buffer when we get close to the
	191	* end of it. Until we get to this offset, we don't need to check
	192	* for overflow however.
	193	*/
	194	safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
	195
ba2dbf30	196	for (i = 0; i < fromwords; i++) {
b2910307 NA	197	ftmp[0] = get_unaligned_le16(&from[i]);
b2910307 NA	198	if (ftmp[0] == 0)
ba2dbf30	199	break;
b2910307 NA	200	if (i + 1 < fromwords)
	201	ftmp[1] = get_unaligned_le16(&from[i + 1]);
	202	else
	203	ftmp[1] = 0;
	204	if (i + 2 < fromwords)
	205	ftmp[2] = get_unaligned_le16(&from[i + 2]);
	206	else
	207	ftmp[2] = 0;
ba2dbf30	208
7fabf0c9 JL	209	/*
	210	* check to see if converting this character might make the
	211	* conversion bleed into the null terminator
	212	*/
	213	if (outlen >= safelen) {
b693855f	214	charlen = cifs_mapchar(tmp, ftmp, codepage, map_type);
7fabf0c9 JL	215	if ((outlen + charlen) > (tolen - nullsize))
	216	break;
	217	}
	218
	219	/* put converted char into 'to' buffer */
b693855f	220	charlen = cifs_mapchar(&to[outlen], ftmp, codepage, map_type);
7fabf0c9	221	outlen += charlen;
b2910307 NA	222
	223	/* charlen (=bytes of UTF-8 for 1 character)
	224	* 4bytes UTF-8(surrogate pair) is charlen=4
	225	* (4bytes UTF-16 code)
	226	* 7-8bytes UTF-8(IVS) is charlen=3+4 or 4+4
	227	* (2 UTF-8 pairs divided to 2 UTF-16 pairs) */
	228	if (charlen == 4)
	229	i++;
	230	else if (charlen >= 5)
	231	/* 5-6bytes UTF-8 */
	232	i += 2;
7fabf0c9 JL	233	}
	234
	235	/* properly null-terminate string */
	236	for (i = 0; i < nullsize; i++)
	237	to[outlen++] = 0;
	238
	239	return outlen;
	240	}
	241
1da177e4	242	/*
acbbb76a	243	* NAME: cifs_strtoUTF16()
1da177e4 LT	244	*
	245	* FUNCTION: Convert character string to unicode string
	246	*
	247	*/
	248	int
acbbb76a	249	cifs_strtoUTF16(__le16 to, const char from, int len,
1da177e4 LT	250	const struct nls_table *codepage)
	251	{
	252	int charlen;
	253	int i;
ba2dbf30	254	wchar_t wchar_to; /* needed to quiet sparse */
1da177e4	255
fd3ba42c FZ	256	/* special case for utf8 to handle no plane0 chars */
	257	if (!strcmp(codepage->charset, "utf8")) {
	258	/*
	259	* convert utf8 -> utf16, we assume we have enough space
	260	* as caller should have assumed conversion does not overflow
	261	* in destination len is length in wchar_t units (16bits)
	262	*/
	263	i = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,
	264	(wchar_t *) to, len);
	265
	266	/* if success terminate and exit */
	267	if (i >= 0)
	268	goto success;
	269	/*
	270	* if fails fall back to UCS encoding as this
	271	* function should not return negative values
	272	* currently can fail only if source contains
	273	* invalid encoded characters
	274	*/
	275	}
	276
1da177e4	277	for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
ba2dbf30	278	charlen = codepage->char2uni(from, len, &wchar_to);
1da177e4	279	if (charlen < 1) {
f96637be JP	280	cifs_dbg(VFS, "strtoUTF16: char2uni of 0x%x returned %d\n",
f96637be JP	281	*from, charlen);
69114089	282	/* A question mark */
ba2dbf30	283	wchar_to = 0x003f;
1da177e4	284	charlen = 1;
ba2dbf30 JL	285	}
ba2dbf30 JL	286	put_unaligned_le16(wchar_to, &to[i]);
1da177e4 LT	287	}
1da177e4 LT	288
fd3ba42c	289	success:
ba2dbf30	290	put_unaligned_le16(0, &to[i]);
1da177e4 LT	291	return i;
	292	}
	293
b2910307 NA	294	/*
	295	* cifs_utf16_bytes - how long will a string be after conversion?
	296	* @utf16 - pointer to input string
	297	* @maxbytes - don't go past this many bytes of input string
	298	* @codepage - destination codepage
	299	*
	300	* Walk a utf16le string and return the number of bytes that the string will
	301	* be after being converted to the given charset, not including any null
	302	* termination required. Don't walk past maxbytes in the source buffer.
	303	*/
	304	int
	305	cifs_utf16_bytes(const __le16 *from, int maxbytes,
	306	const struct nls_table *codepage)
	307	{
	308	int i;
	309	int charlen, outlen = 0;
	310	int maxwords = maxbytes / 2;
	311	char tmp[NLS_MAX_CHARSET_SIZE];
	312	__u16 ftmp[3];
	313
	314	for (i = 0; i < maxwords; i++) {
	315	ftmp[0] = get_unaligned_le16(&from[i]);
	316	if (ftmp[0] == 0)
	317	break;
	318	if (i + 1 < maxwords)
	319	ftmp[1] = get_unaligned_le16(&from[i + 1]);
	320	else
	321	ftmp[1] = 0;
	322	if (i + 2 < maxwords)
	323	ftmp[2] = get_unaligned_le16(&from[i + 2]);
	324	else
	325	ftmp[2] = 0;
	326
	327	charlen = cifs_mapchar(tmp, ftmp, codepage, NO_MAP_UNI_RSVD);
	328	outlen += charlen;
	329	}
	330
	331	return outlen;
	332	}
	333
066ce689	334	/*
acbbb76a SF	335	* cifs_strndup_from_utf16 - copy a string from wire format to the local
acbbb76a SF	336	* codepage
066ce689 JL	337	* @src - source string
	338	* @maxlen - don't walk past this many bytes in the source string
	339	* @is_unicode - is this a unicode string?
	340	* @codepage - destination codepage
	341	*
	342	* Take a string given by the server, convert it to the local codepage and
	343	* put it in a new buffer. Returns a pointer to the new string or NULL on
	344	* error.
	345	*/
	346	char *
acbbb76a SF	347	cifs_strndup_from_utf16(const char *src, const int maxlen,
acbbb76a SF	348	const bool is_unicode, const struct nls_table *codepage)
066ce689 JL	349	{
	350	int len;
	351	char *dst;
	352
	353	if (is_unicode) {
acbbb76a	354	len = cifs_utf16_bytes((__le16 *) src, maxlen, codepage);
066ce689 JL	355	len += nls_nullsize(codepage);
	356	dst = kmalloc(len, GFP_KERNEL);
	357	if (!dst)
	358	return NULL;
acbbb76a	359	cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage,
f980d055	360	NO_MAP_UNI_RSVD);
066ce689	361	} else {
f980d055	362	dst = kstrndup(src, maxlen, GFP_KERNEL);
066ce689 JL	363	}
	364
	365	return dst;
	366	}
	367
a4153cb1 SF	368	static __le16 convert_to_sfu_char(char src_char)
	369	{
	370	__le16 dest_char;
	371
	372	switch (src_char) {
	373	case ':':
	374	dest_char = cpu_to_le16(UNI_COLON);
	375	break;
	376	case '*':
	377	dest_char = cpu_to_le16(UNI_ASTERISK);
	378	break;
	379	case '?':
	380	dest_char = cpu_to_le16(UNI_QUESTION);
	381	break;
	382	case '<':
	383	dest_char = cpu_to_le16(UNI_LESSTHAN);
	384	break;
	385	case '>':
	386	dest_char = cpu_to_le16(UNI_GRTRTHAN);
	387	break;
	388	case '\|':
	389	dest_char = cpu_to_le16(UNI_PIPE);
	390	break;
	391	default:
	392	dest_char = 0;
	393	}
	394
	395	return dest_char;
	396	}
	397
45e8a258	398	static __le16 convert_to_sfm_char(char src_char, bool end_of_string)
a4153cb1 SF	399	{
	400	__le16 dest_char;
	401
7e46f090 BJ	402	if (src_char >= 0x01 && src_char <= 0x1F) {
	403	dest_char = cpu_to_le16(src_char + 0xF000);
	404	return dest_char;
	405	}
a4153cb1 SF	406	switch (src_char) {
	407	case ':':
	408	dest_char = cpu_to_le16(SFM_COLON);
	409	break;
85435d7a BJ	410	case '"':
	411	dest_char = cpu_to_le16(SFM_DOUBLEQUOTE);
	412	break;
a4153cb1 SF	413	case '*':
	414	dest_char = cpu_to_le16(SFM_ASTERISK);
	415	break;
	416	case '?':
	417	dest_char = cpu_to_le16(SFM_QUESTION);
	418	break;
	419	case '<':
	420	dest_char = cpu_to_le16(SFM_LESSTHAN);
	421	break;
	422	case '>':
	423	dest_char = cpu_to_le16(SFM_GRTRTHAN);
	424	break;
	425	case '\|':
	426	dest_char = cpu_to_le16(SFM_PIPE);
	427	break;
45e8a258 SF	428	case '.':
	429	if (end_of_string)
	430	dest_char = cpu_to_le16(SFM_PERIOD);
	431	else
	432	dest_char = 0;
	433	break;
	434	case ' ':
	435	if (end_of_string)
	436	dest_char = cpu_to_le16(SFM_SPACE);
	437	else
	438	dest_char = 0;
	439	break;
a4153cb1 SF	440	default:
	441	dest_char = 0;
	442	}
	443
	444	return dest_char;
	445	}
	446
84cdf74e JL	447	/*
	448	* Convert 16 bit Unicode pathname to wire format from string in current code
	449	* page. Conversion may involve remapping up the six characters that are
	450	* only legal in POSIX-like OS (if they are present in the string). Path
	451	* names are little endian 16 bit Unicode on the wire
	452	*/
	453	int
acbbb76a	454	cifsConvertToUTF16(__le16 target, const char source, int srclen,
a4153cb1	455	const struct nls_table *cp, int map_chars)
84cdf74e	456	{
ce36d9ab SF	457	int i, charlen;
ce36d9ab SF	458	int j = 0;
84cdf74e	459	char src_char;
581ade4d JL	460	__le16 dst_char;
581ade4d JL	461	wchar_t tmp;
b2910307 NA	462	wchar_t wchar_to; / UTF-16 */
	463	int ret;
	464	unicode_t u;
84cdf74e	465
a4153cb1	466	if (map_chars == NO_MAP_UNI_RSVD)
acbbb76a	467	return cifs_strtoUTF16(target, source, PATH_MAX, cp);
84cdf74e	468
b2910307 NA	469	wchar_to = kzalloc(6, GFP_KERNEL);
b2910307 NA	470
ce36d9ab	471	for (i = 0; i < srclen; j++) {
84cdf74e	472	src_char = source[i];
11379b5e	473	charlen = 1;
a4153cb1 SF	474
	475	/* check if end of string */
	476	if (src_char == 0)
acbbb76a	477	goto ctoUTF16_out;
a4153cb1 SF	478
	479	/* see if we must remap this char */
	480	if (map_chars == SFU_MAP_UNI_RSVD)
	481	dst_char = convert_to_sfu_char(src_char);
45e8a258 SF	482	else if (map_chars == SFM_MAP_UNI_RSVD) {
	483	bool end_of_string;
	484
57c17607 BP	485	/**
	486	* Remap spaces and periods found at the end of every
	487	* component of the path. The special cases of '.' and
	488	* '..' do not need to be dealt with explicitly because
	489	* they are addressed in namei.c:link_path_walk().
	490	**/
	491	if ((i == srclen - 1) \|\| (source[i+1] == '\\'))
45e8a258 SF	492	end_of_string = true;
	493	else
	494	end_of_string = false;
	495
	496	dst_char = convert_to_sfm_char(src_char, end_of_string);
	497	} else
a4153cb1	498	dst_char = 0;
84cdf74e JL	499	/*
	500	* FIXME: We can not handle remapping backslash (UNI_SLASH)
	501	* until all the calls to build_path_from_dentry are modified,
	502	* as they use backslash as separator.
	503	*/
a4153cb1	504	if (dst_char == 0) {
581ade4d JL	505	charlen = cp->char2uni(source + i, srclen - i, &tmp);
	506	dst_char = cpu_to_le16(tmp);
	507
84cdf74e JL	508	/*
	509	* if no match, use question mark, which at least in
	510	* some cases serves as wild card
	511	*/
b2910307 NA	512	if (charlen > 0)
	513	goto ctoUTF16;
	514
	515	/* convert SURROGATE_PAIR */
	516	if (strcmp(cp->charset, "utf8") \|\| !wchar_to)
	517	goto unknown;
	518	if (*(source + i) & 0x80) {
	519	charlen = utf8_to_utf32(source + i, 6, &u);
	520	if (charlen < 0)
	521	goto unknown;
	522	} else
	523	goto unknown;
	524	ret = utf8s_to_utf16s(source + i, charlen,
	525	UTF16_LITTLE_ENDIAN,
	526	wchar_to, 6);
	527	if (ret < 0)
	528	goto unknown;
	529
	530	i += charlen;
	531	dst_char = cpu_to_le16(*wchar_to);
	532	if (charlen <= 3)
	533	/* 1-3bytes UTF-8 to 2bytes UTF-16 */
	534	put_unaligned(dst_char, &target[j]);
	535	else if (charlen == 4) {
	536	/* 4bytes UTF-8(surrogate pair) to 4bytes UTF-16
	537	* 7-8bytes UTF-8(IVS) divided to 2 UTF-16
	538	* (charlen=3+4 or 4+4) */
	539	put_unaligned(dst_char, &target[j]);
	540	dst_char = cpu_to_le16(*(wchar_to + 1));
	541	j++;
	542	put_unaligned(dst_char, &target[j]);
	543	} else if (charlen >= 5) {
	544	/* 5-6bytes UTF-8 to 6bytes UTF-16 */
	545	put_unaligned(dst_char, &target[j]);
	546	dst_char = cpu_to_le16(*(wchar_to + 1));
	547	j++;
	548	put_unaligned(dst_char, &target[j]);
	549	dst_char = cpu_to_le16(*(wchar_to + 2));
	550	j++;
	551	put_unaligned(dst_char, &target[j]);
84cdf74e	552	}
b2910307 NA	553	continue;
	554
	555	unknown:
	556	dst_char = cpu_to_le16(0x003f);
	557	charlen = 1;
84cdf74e	558	}
b2910307 NA	559
b2910307 NA	560	ctoUTF16:
11379b5e JL	561	/*
	562	* character may take more than one byte in the source string,
	563	* but will take exactly two bytes in the target string
	564	*/
	565	i += charlen;
581ade4d	566	put_unaligned(dst_char, &target[j]);
84cdf74e JL	567	}
84cdf74e JL	568
acbbb76a	569	ctoUTF16_out:
ce36d9ab	570	put_unaligned(0, &target[j]); /* Null terminate target unicode string */
b2910307	571	kfree(wchar_to);
c73f6939	572	return j;
84cdf74e	573	}
2503a0db	574
2503a0db PS	575	/*
	576	* cifs_local_to_utf16_bytes - how long will a string be after conversion?
	577	* @from - pointer to input string
	578	* @maxbytes - don't go past this many bytes of input string
	579	* @codepage - source codepage
	580	*
	581	* Walk a string and return the number of bytes that the string will
	582	* be after being converted to the given charset, not including any null
	583	* termination required. Don't walk past maxbytes in the source buffer.
	584	*/
	585
	586	static int
	587	cifs_local_to_utf16_bytes(const char *from, int len,
	588	const struct nls_table *codepage)
	589	{
	590	int charlen;
	591	int i;
	592	wchar_t wchar_to;
	593
	594	for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
	595	charlen = codepage->char2uni(from, len, &wchar_to);
	596	/* Failed conversion defaults to a question mark */
	597	if (charlen < 1)
	598	charlen = 1;
	599	}
	600	return 2 * i; /* UTF16 characters are two bytes */
	601	}
	602
	603	/*
	604	* cifs_strndup_to_utf16 - copy a string to wire format from the local codepage
	605	* @src - source string
	606	* @maxlen - don't walk past this many bytes in the source string
	607	* @utf16_len - the length of the allocated string in bytes (including null)
	608	* @cp - source codepage
	609	* @remap - map special chars
	610	*
	611	* Take a string convert it from the local codepage to UTF16 and
	612	* put it in a new buffer. Returns a pointer to the new string or NULL on
	613	* error.
	614	*/
	615	__le16 *
	616	cifs_strndup_to_utf16(const char src, const int maxlen, int utf16_len,
	617	const struct nls_table *cp, int remap)
	618	{
	619	int len;
	620	__le16 *dst;
	621
	622	len = cifs_local_to_utf16_bytes(src, maxlen, cp);
	623	len += 2; /* NULL */
	624	dst = kmalloc(len, GFP_KERNEL);
	625	if (!dst) {
	626	*utf16_len = 0;
	627	return NULL;
	628	}
	629	cifsConvertToUTF16(dst, src, strlen(src), cp, remap);
	630	*utf16_len = len;
	631	return dst;
	632	}