// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Some of the source code in this file came from fs/cifs/cifs_unicode.c
*
* Copyright (c) International Business Machines Corp., 2000,2009
* Modified by Steve French ([email protected])
* Modified by Namjae Jeon ([email protected])
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/unaligned.h>
#include "glob.h"
#include "unicode.h"
#include "smb_common.h"
/*
* cifs_mapchar() - convert a host-endian char to proper char in codepage
* @target: where converted character should be copied
* @from: host-endian source string
* @cp: codepage to which character should be converted
* @mapchar: should character be mapped according to mapchars mount option?
*
* 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).
*
* Return: string length after conversion
*/
static int
cifs_mapchar(char *target, const __u16 *from, const struct nls_table *cp,
bool mapchar)
{
int len = 1;
__u16 src_char;
src_char = *from;
if (!mapchar)
goto cp_convert;
/*
* 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:
goto cp_convert;
}
out:
return len;
cp_convert:
len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);
if (len <= 0)
goto surrogate_pair;
goto out;
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;
goto out;
}
/*
* smb_utf16_bytes() - compute converted string length
* @from: pointer to input string
* @maxbytes: input string length
* @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.
*
* Return: string length after conversion
*/
static int smb_utf16_bytes(const __le16 *from, int maxbytes,
const struct nls_table *codepage)
{
int i, j;
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;
for (j = 1; j <= 2; j++) {
if (i + j < maxwords)
ftmp[j] = get_unaligned_le16(&from[i + j]);
else
ftmp[j] = 0;
}
charlen = cifs_mapchar(tmp, ftmp, codepage, 0);
if (charlen > 0)
outlen += charlen;
else
outlen++;
}
return outlen;
}
/*
* smb_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.
*
* Return: string length after conversion
*/
static int smb_from_utf16(char *to, const __le16 *from, int tolen, int fromlen,
const struct nls_table *codepage, bool mapchar)
{
int i, j, 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;
for (j = 1; j <= 2; j++) {
if (i + j < fromwords)
ftmp[j] = get_unaligned_le16(&from[i + j]);
else
ftmp[j] = 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, mapchar);
if ((outlen + charlen) > (tolen - nullsize))
break;
}
/* put converted char into 'to' buffer */
charlen = cifs_mapchar(&to[outlen], ftmp, codepage, mapchar);
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;
}
/*
* smb_strtoUTF16() - Convert character string to unicode string
* @to: destination buffer
* @from: source buffer
* @len: destination buffer size (in bytes)
* @codepage: codepage to which characters should be converted
*
* Return: string length after conversion
*/
int smb_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 > 0 && *from; i++, from += charlen, len -= charlen) {
charlen = codepage->char2uni(from, len, &wchar_to);
if (charlen < 1) {
/* A question mark */
wchar_to = 0x003f;
charlen = 1;
}
put_unaligned_le16(wchar_to, &to[i]);
}
success:
put_unaligned_le16(0, &to[i]);
return i;
}
/*
* smb_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.
*
* Return: destination string buffer or error ptr
*/
char *smb_strndup_from_utf16(const char *src, const int maxlen,
const bool is_unicode,
const struct nls_table *codepage)
{
int len, ret;
char *dst;
if (is_unicode) {
len = smb_utf16_bytes((__le16 *)src, maxlen, codepage);
len += nls_nullsize(codepage);
dst = kmalloc(len, GFP_KERNEL);
if (!dst)
return ERR_PTR(-ENOMEM);
ret = smb_from_utf16(dst, (__le16 *)src, len, maxlen, codepage,
false);
if (ret < 0) {
kfree(dst);
return ERR_PTR(-EINVAL);
}
} else {
len = strnlen(src, maxlen);
len++;
dst = kmalloc(len, GFP_KERNEL);
if (!dst)
return ERR_PTR(-ENOMEM);
strscpy(dst, src, len);
}
return dst;
}
/*
* 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
*/
/*
* smbConvertToUTF16() - convert string from local charset to utf16
* @target: destination buffer
* @source: source buffer
* @srclen: source buffer size (in bytes)
* @cp: codepage to which characters should be converted
* @mapchar: should characters be remapped according to the mapchars option?
*
* 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
*
* Return: char length after conversion
*/
int smbConvertToUTF16(__le16 *target, const char *source, int srclen,
const struct nls_table *cp, int mapchars)
{
int i, j, charlen;
char src_char;
__le16 dst_char;
wchar_t tmp;
wchar_t wchar_to[6]; /* UTF-16 */
int ret;
unicode_t u;
if (!mapchars)
return smb_strtoUTF16(target, source, srclen, cp);
for (i = 0, j = 0; i < srclen; j++) {
src_char = source[i];
charlen = 1;
switch (src_char) {
case 0:
put_unaligned(0, &target[j]);
return j;
case ':':
dst_char = cpu_to_le16(UNI_COLON);
break;
case '*':
dst_char = cpu_to_le16(UNI_ASTERISK);
break;
case '?':
dst_char = cpu_to_le16(UNI_QUESTION);
break;
case '<':
dst_char = cpu_to_le16(UNI_LESSTHAN);
break;
case '>':
dst_char = cpu_to_le16(UNI_GRTRTHAN);
break;
case '|':
dst_char = cpu_to_le16(UNI_PIPE);
break;
/*
* 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.
*/
default:
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"))
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]);
}
return j;
}
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