643 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 *4 * Copyright (c) International Business Machines Corp., 2000,20095 * Modified by Steve French (sfrench@us.ibm.com)6 */7#include <linux/fs.h>8#include <linux/slab.h>9#include "cifs_fs_sb.h"10#include "cifs_unicode.h"11#include "cifspdu.h"12#include "cifsglob.h"13#include "cifs_debug.h"14 15int cifs_remap(struct cifs_sb_info *cifs_sb)16{17 int map_type;18 19 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)20 map_type = SFM_MAP_UNI_RSVD;21 else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)22 map_type = SFU_MAP_UNI_RSVD;23 else24 map_type = NO_MAP_UNI_RSVD;25 26 return map_type;27}28 29/* Convert character using the SFU - "Services for Unix" remapping range */30static bool31convert_sfu_char(const __u16 src_char, char *target)32{33 /*34 * BB: Cannot handle remapping UNI_SLASH until all the calls to35 * build_path_from_dentry are modified, as they use slash as36 * separator.37 */38 switch (src_char) {39 case UNI_COLON:40 *target = ':';41 break;42 case UNI_ASTERISK:43 *target = '*';44 break;45 case UNI_QUESTION:46 *target = '?';47 break;48 case UNI_PIPE:49 *target = '|';50 break;51 case UNI_GRTRTHAN:52 *target = '>';53 break;54 case UNI_LESSTHAN:55 *target = '<';56 break;57 default:58 return false;59 }60 return true;61}62 63/* Convert character using the SFM - "Services for Mac" remapping range */64static bool65convert_sfm_char(const __u16 src_char, char *target)66{67 if (src_char >= 0xF001 && src_char <= 0xF01F) {68 *target = src_char - 0xF000;69 return true;70 }71 switch (src_char) {72 case SFM_COLON:73 *target = ':';74 break;75 case SFM_DOUBLEQUOTE:76 *target = '"';77 break;78 case SFM_ASTERISK:79 *target = '*';80 break;81 case SFM_QUESTION:82 *target = '?';83 break;84 case SFM_PIPE:85 *target = '|';86 break;87 case SFM_GRTRTHAN:88 *target = '>';89 break;90 case SFM_LESSTHAN:91 *target = '<';92 break;93 case SFM_SPACE:94 *target = ' ';95 break;96 case SFM_PERIOD:97 *target = '.';98 break;99 default:100 return false;101 }102 return true;103}104 105 106/*107 * cifs_mapchar - convert a host-endian char to proper char in codepage108 * @target - where converted character should be copied109 * @src_char - 2 byte host-endian source character110 * @cp - codepage to which character should be converted111 * @map_type - How should the 7 NTFS/SMB reserved characters be mapped to UCS2?112 *113 * This function handles the conversion of a single character. It is the114 * responsibility of the caller to ensure that the target buffer is large115 * enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).116 */117static int118cifs_mapchar(char *target, const __u16 *from, const struct nls_table *cp,119 int maptype)120{121 int len = 1;122 __u16 src_char;123 124 src_char = *from;125 126 if ((maptype == SFM_MAP_UNI_RSVD) && convert_sfm_char(src_char, target))127 return len;128 else if ((maptype == SFU_MAP_UNI_RSVD) &&129 convert_sfu_char(src_char, target))130 return len;131 132 /* if character not one of seven in special remap set */133 len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);134 if (len <= 0)135 goto surrogate_pair;136 137 return len;138 139surrogate_pair:140 /* convert SURROGATE_PAIR and IVS */141 if (strcmp(cp->charset, "utf8"))142 goto unknown;143 len = utf16s_to_utf8s(from, 3, UTF16_LITTLE_ENDIAN, target, 6);144 if (len <= 0)145 goto unknown;146 return len;147 148unknown:149 *target = '?';150 len = 1;151 return len;152}153 154/*155 * cifs_from_utf16 - convert utf16le string to local charset156 * @to - destination buffer157 * @from - source buffer158 * @tolen - destination buffer size (in bytes)159 * @fromlen - source buffer size (in bytes)160 * @codepage - codepage to which characters should be converted161 * @mapchar - should characters be remapped according to the mapchars option?162 *163 * Convert a little-endian utf16le string (as sent by the server) to a string164 * in the provided codepage. The tolen and fromlen parameters are to ensure165 * that the code doesn't walk off of the end of the buffer (which is always166 * a danger if the alignment of the source buffer is off). The destination167 * string is always properly null terminated and fits in the destination168 * buffer. Returns the length of the destination string in bytes (including169 * null terminator).170 *171 * Note that some windows versions actually send multiword UTF-16 characters172 * instead of straight UTF16-2. The linux nls routines however aren't able to173 * deal with those characters properly. In the event that we get some of174 * those characters, they won't be translated properly.175 */176int177cifs_from_utf16(char *to, const __le16 *from, int tolen, int fromlen,178 const struct nls_table *codepage, int map_type)179{180 int i, charlen, safelen;181 int outlen = 0;182 int nullsize = nls_nullsize(codepage);183 int fromwords = fromlen / 2;184 char tmp[NLS_MAX_CHARSET_SIZE];185 __u16 ftmp[3]; /* ftmp[3] = 3array x 2bytes = 6bytes UTF-16 */186 187 /*188 * because the chars can be of varying widths, we need to take care189 * not to overflow the destination buffer when we get close to the190 * end of it. Until we get to this offset, we don't need to check191 * for overflow however.192 */193 safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);194 195 for (i = 0; i < fromwords; i++) {196 ftmp[0] = get_unaligned_le16(&from[i]);197 if (ftmp[0] == 0)198 break;199 if (i + 1 < fromwords)200 ftmp[1] = get_unaligned_le16(&from[i + 1]);201 else202 ftmp[1] = 0;203 if (i + 2 < fromwords)204 ftmp[2] = get_unaligned_le16(&from[i + 2]);205 else206 ftmp[2] = 0;207 208 /*209 * check to see if converting this character might make the210 * conversion bleed into the null terminator211 */212 if (outlen >= safelen) {213 charlen = cifs_mapchar(tmp, ftmp, codepage, map_type);214 if ((outlen + charlen) > (tolen - nullsize))215 break;216 }217 218 /* put converted char into 'to' buffer */219 charlen = cifs_mapchar(&to[outlen], ftmp, codepage, map_type);220 outlen += charlen;221 222 /* charlen (=bytes of UTF-8 for 1 character)223 * 4bytes UTF-8(surrogate pair) is charlen=4224 * (4bytes UTF-16 code)225 * 7-8bytes UTF-8(IVS) is charlen=3+4 or 4+4226 * (2 UTF-8 pairs divided to 2 UTF-16 pairs) */227 if (charlen == 4)228 i++;229 else if (charlen >= 5)230 /* 5-6bytes UTF-8 */231 i += 2;232 }233 234 /* properly null-terminate string */235 for (i = 0; i < nullsize; i++)236 to[outlen++] = 0;237 238 return outlen;239}240 241/*242 * NAME: cifs_strtoUTF16()243 *244 * FUNCTION: Convert character string to unicode string245 *246 */247int248cifs_strtoUTF16(__le16 *to, const char *from, int len,249 const struct nls_table *codepage)250{251 int charlen;252 int i;253 wchar_t wchar_to; /* needed to quiet sparse */254 255 /* special case for utf8 to handle no plane0 chars */256 if (!strcmp(codepage->charset, "utf8")) {257 /*258 * convert utf8 -> utf16, we assume we have enough space259 * as caller should have assumed conversion does not overflow260 * in destination len is length in wchar_t units (16bits)261 */262 i = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,263 (wchar_t *) to, len);264 265 /* if success terminate and exit */266 if (i >= 0)267 goto success;268 /*269 * if fails fall back to UCS encoding as this270 * function should not return negative values271 * currently can fail only if source contains272 * invalid encoded characters273 */274 }275 276 for (i = 0; len && *from; i++, from += charlen, len -= charlen) {277 charlen = codepage->char2uni(from, len, &wchar_to);278 if (charlen < 1) {279 cifs_dbg(VFS, "strtoUTF16: char2uni of 0x%x returned %d\n",280 *from, charlen);281 /* A question mark */282 wchar_to = 0x003f;283 charlen = 1;284 }285 put_unaligned_le16(wchar_to, &to[i]);286 }287 288success:289 put_unaligned_le16(0, &to[i]);290 return i;291}292 293/*294 * cifs_utf16_bytes - how long will a string be after conversion?295 * @utf16 - pointer to input string296 * @maxbytes - don't go past this many bytes of input string297 * @codepage - destination codepage298 *299 * Walk a utf16le string and return the number of bytes that the string will300 * be after being converted to the given charset, not including any null301 * termination required. Don't walk past maxbytes in the source buffer.302 */303int304cifs_utf16_bytes(const __le16 *from, int maxbytes,305 const struct nls_table *codepage)306{307 int i;308 int charlen, outlen = 0;309 int maxwords = maxbytes / 2;310 char tmp[NLS_MAX_CHARSET_SIZE];311 __u16 ftmp[3];312 313 for (i = 0; i < maxwords; i++) {314 ftmp[0] = get_unaligned_le16(&from[i]);315 if (ftmp[0] == 0)316 break;317 if (i + 1 < maxwords)318 ftmp[1] = get_unaligned_le16(&from[i + 1]);319 else320 ftmp[1] = 0;321 if (i + 2 < maxwords)322 ftmp[2] = get_unaligned_le16(&from[i + 2]);323 else324 ftmp[2] = 0;325 326 charlen = cifs_mapchar(tmp, ftmp, codepage, NO_MAP_UNI_RSVD);327 outlen += charlen;328 }329 330 return outlen;331}332 333/*334 * cifs_strndup_from_utf16 - copy a string from wire format to the local335 * codepage336 * @src - source string337 * @maxlen - don't walk past this many bytes in the source string338 * @is_unicode - is this a unicode string?339 * @codepage - destination codepage340 *341 * Take a string given by the server, convert it to the local codepage and342 * put it in a new buffer. Returns a pointer to the new string or NULL on343 * error.344 */345char *346cifs_strndup_from_utf16(const char *src, const int maxlen,347 const bool is_unicode, const struct nls_table *codepage)348{349 int len;350 char *dst;351 352 if (is_unicode) {353 len = cifs_utf16_bytes((__le16 *) src, maxlen, codepage);354 len += nls_nullsize(codepage);355 dst = kmalloc(len, GFP_KERNEL);356 if (!dst)357 return NULL;358 cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage,359 NO_MAP_UNI_RSVD);360 } else {361 dst = kstrndup(src, maxlen, GFP_KERNEL);362 }363 364 return dst;365}366 367static __le16 convert_to_sfu_char(char src_char)368{369 __le16 dest_char;370 371 switch (src_char) {372 case ':':373 dest_char = cpu_to_le16(UNI_COLON);374 break;375 case '*':376 dest_char = cpu_to_le16(UNI_ASTERISK);377 break;378 case '?':379 dest_char = cpu_to_le16(UNI_QUESTION);380 break;381 case '<':382 dest_char = cpu_to_le16(UNI_LESSTHAN);383 break;384 case '>':385 dest_char = cpu_to_le16(UNI_GRTRTHAN);386 break;387 case '|':388 dest_char = cpu_to_le16(UNI_PIPE);389 break;390 default:391 dest_char = 0;392 }393 394 return dest_char;395}396 397static __le16 convert_to_sfm_char(char src_char, bool end_of_string)398{399 __le16 dest_char;400 401 if (src_char >= 0x01 && src_char <= 0x1F) {402 dest_char = cpu_to_le16(src_char + 0xF000);403 return dest_char;404 }405 switch (src_char) {406 case ':':407 dest_char = cpu_to_le16(SFM_COLON);408 break;409 case '"':410 dest_char = cpu_to_le16(SFM_DOUBLEQUOTE);411 break;412 case '*':413 dest_char = cpu_to_le16(SFM_ASTERISK);414 break;415 case '?':416 dest_char = cpu_to_le16(SFM_QUESTION);417 break;418 case '<':419 dest_char = cpu_to_le16(SFM_LESSTHAN);420 break;421 case '>':422 dest_char = cpu_to_le16(SFM_GRTRTHAN);423 break;424 case '|':425 dest_char = cpu_to_le16(SFM_PIPE);426 break;427 case '.':428 if (end_of_string)429 dest_char = cpu_to_le16(SFM_PERIOD);430 else431 dest_char = 0;432 break;433 case ' ':434 if (end_of_string)435 dest_char = cpu_to_le16(SFM_SPACE);436 else437 dest_char = 0;438 break;439 default:440 dest_char = 0;441 }442 443 return dest_char;444}445 446/*447 * Convert 16 bit Unicode pathname to wire format from string in current code448 * page. Conversion may involve remapping up the six characters that are449 * only legal in POSIX-like OS (if they are present in the string). Path450 * names are little endian 16 bit Unicode on the wire451 */452int453cifsConvertToUTF16(__le16 *target, const char *source, int srclen,454 const struct nls_table *cp, int map_chars)455{456 int i, charlen;457 int j = 0;458 char src_char;459 __le16 dst_char;460 wchar_t tmp;461 wchar_t *wchar_to; /* UTF-16 */462 int ret;463 unicode_t u;464 465 if (map_chars == NO_MAP_UNI_RSVD)466 return cifs_strtoUTF16(target, source, PATH_MAX, cp);467 468 wchar_to = kzalloc(6, GFP_KERNEL);469 470 for (i = 0; i < srclen; j++) {471 src_char = source[i];472 charlen = 1;473 474 /* check if end of string */475 if (src_char == 0)476 goto ctoUTF16_out;477 478 /* see if we must remap this char */479 if (map_chars == SFU_MAP_UNI_RSVD)480 dst_char = convert_to_sfu_char(src_char);481 else if (map_chars == SFM_MAP_UNI_RSVD) {482 bool end_of_string;483 484 /**485 * Remap spaces and periods found at the end of every486 * component of the path. The special cases of '.' and487 * '..' are need to be handled because of symlinks.488 * They are treated as non-end-of-string to avoid489 * remapping and breaking symlinks pointing to . or ..490 **/491 if ((i == 0 || source[i-1] == '\\') &&492 source[i] == '.' &&493 (i == srclen-1 || source[i+1] == '\\'))494 end_of_string = false; /* "." case */495 else if (i >= 1 &&496 (i == 1 || source[i-2] == '\\') &&497 source[i-1] == '.' &&498 source[i] == '.' &&499 (i == srclen-1 || source[i+1] == '\\'))500 end_of_string = false; /* ".." case */501 else if ((i == srclen - 1) || (source[i+1] == '\\'))502 end_of_string = true;503 else504 end_of_string = false;505 506 dst_char = convert_to_sfm_char(src_char, end_of_string);507 } else508 dst_char = 0;509 /*510 * FIXME: We can not handle remapping backslash (UNI_SLASH)511 * until all the calls to build_path_from_dentry are modified,512 * as they use backslash as separator.513 */514 if (dst_char == 0) {515 charlen = cp->char2uni(source + i, srclen - i, &tmp);516 dst_char = cpu_to_le16(tmp);517 518 /*519 * if no match, use question mark, which at least in520 * some cases serves as wild card521 */522 if (charlen > 0)523 goto ctoUTF16;524 525 /* convert SURROGATE_PAIR */526 if (strcmp(cp->charset, "utf8") || !wchar_to)527 goto unknown;528 if (*(source + i) & 0x80) {529 charlen = utf8_to_utf32(source + i, 6, &u);530 if (charlen < 0)531 goto unknown;532 } else533 goto unknown;534 ret = utf8s_to_utf16s(source + i, charlen,535 UTF16_LITTLE_ENDIAN,536 wchar_to, 6);537 if (ret < 0)538 goto unknown;539 540 i += charlen;541 dst_char = cpu_to_le16(*wchar_to);542 if (charlen <= 3)543 /* 1-3bytes UTF-8 to 2bytes UTF-16 */544 put_unaligned(dst_char, &target[j]);545 else if (charlen == 4) {546 /* 4bytes UTF-8(surrogate pair) to 4bytes UTF-16547 * 7-8bytes UTF-8(IVS) divided to 2 UTF-16548 * (charlen=3+4 or 4+4) */549 put_unaligned(dst_char, &target[j]);550 dst_char = cpu_to_le16(*(wchar_to + 1));551 j++;552 put_unaligned(dst_char, &target[j]);553 } else if (charlen >= 5) {554 /* 5-6bytes UTF-8 to 6bytes UTF-16 */555 put_unaligned(dst_char, &target[j]);556 dst_char = cpu_to_le16(*(wchar_to + 1));557 j++;558 put_unaligned(dst_char, &target[j]);559 dst_char = cpu_to_le16(*(wchar_to + 2));560 j++;561 put_unaligned(dst_char, &target[j]);562 }563 continue;564 565unknown:566 dst_char = cpu_to_le16(0x003f);567 charlen = 1;568 }569 570ctoUTF16:571 /*572 * character may take more than one byte in the source string,573 * but will take exactly two bytes in the target string574 */575 i += charlen;576 put_unaligned(dst_char, &target[j]);577 }578 579ctoUTF16_out:580 put_unaligned(0, &target[j]); /* Null terminate target unicode string */581 kfree(wchar_to);582 return j;583}584 585/*586 * cifs_local_to_utf16_bytes - how long will a string be after conversion?587 * @from - pointer to input string588 * @maxbytes - don't go past this many bytes of input string589 * @codepage - source codepage590 *591 * Walk a string and return the number of bytes that the string will592 * be after being converted to the given charset, not including any null593 * termination required. Don't walk past maxbytes in the source buffer.594 */595 596static int597cifs_local_to_utf16_bytes(const char *from, int len,598 const struct nls_table *codepage)599{600 int charlen;601 int i;602 wchar_t wchar_to;603 604 for (i = 0; len && *from; i++, from += charlen, len -= charlen) {605 charlen = codepage->char2uni(from, len, &wchar_to);606 /* Failed conversion defaults to a question mark */607 if (charlen < 1)608 charlen = 1;609 }610 return 2 * i; /* UTF16 characters are two bytes */611}612 613/*614 * cifs_strndup_to_utf16 - copy a string to wire format from the local codepage615 * @src - source string616 * @maxlen - don't walk past this many bytes in the source string617 * @utf16_len - the length of the allocated string in bytes (including null)618 * @cp - source codepage619 * @remap - map special chars620 *621 * Take a string convert it from the local codepage to UTF16 and622 * put it in a new buffer. Returns a pointer to the new string or NULL on623 * error.624 */625__le16 *626cifs_strndup_to_utf16(const char *src, const int maxlen, int *utf16_len,627 const struct nls_table *cp, int remap)628{629 int len;630 __le16 *dst;631 632 len = cifs_local_to_utf16_bytes(src, maxlen, cp);633 len += 2; /* NULL */634 dst = kmalloc(len, GFP_KERNEL);635 if (!dst) {636 *utf16_len = 0;637 return NULL;638 }639 cifsConvertToUTF16(dst, src, strlen(src), cp, remap);640 *utf16_len = len;641 return dst;642}643