linux/fs/cifs/cifs_unicode.c
Steve French 099dd788e3 cifs: remove pathname for file from SPDX header
checkpatch complains about source files with filenames (e.g. in
these cases just below the SPDX header in comments at the top of
various files in fs/cifs). It also is helpful to change this now
so will be less confusing when the parent directory is renamed
e.g. from fs/cifs to fs/smb_client (or fs/smbfs)

Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-09-13 14:51:10 -05:00

633 lines
16 KiB
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;
}