// 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 (sfrench@us.ibm.com) * Modified by Namjae Jeon (linkinjeon@kernel.org) */ #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, KSMBD_DEFAULT_GFP); 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, KSMBD_DEFAULT_GFP); 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; }
