diff options
Diffstat (limited to 'fs/smb/server/unicode.c')
| -rw-r--r-- | fs/smb/server/unicode.c | 454 |
1 files changed, 454 insertions, 0 deletions
diff --git a/fs/smb/server/unicode.c b/fs/smb/server/unicode.c new file mode 100644 index 0000000000..43ed29ee44 --- /dev/null +++ b/fs/smb/server/unicode.c @@ -0,0 +1,454 @@ +// 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 <asm/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; +} |