/* * "streamable kanji code filter and converter" * Copyright (c) 1998-2002 HappySize, Inc. All rights reserved. * * LICENSE NOTICES * * This file is part of "streamable kanji code filter and converter", * which is distributed under the terms of GNU Lesser General Public * License (version 2) as published by the Free Software Foundation. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with "streamable kanji code filter and converter"; * if not, write to the Free Software Foundation, Inc., 59 Temple Place, * Suite 330, Boston, MA 02111-1307 USA * * The author of this file: * */ /* * The source code included in this file was separated from mbfilter.c * by moriyoshi koizumi on 4 dec 2002. * */ /* Modified UTF-7 used for 'international mailbox names' in the IMAP protocol * Also known as mUTF-7 * Defined in RFC 3501 5.1.3 (https://tools.ietf.org/html/rfc3501) * * Quoting from the RFC: * *********************************************************************** * In modified UTF-7, printable US-ASCII characters, except for "&", * represent themselves; that is, characters with octet values 0x20-0x25 * and 0x27-0x7e. The character "&" (0x26) is represented by the * two-octet sequence "&-". * * All other characters (octet values 0x00-0x1f and 0x7f-0xff) are * represented in modified BASE64, with a further modification from * UTF-7 that "," is used instead of "/". Modified BASE64 MUST NOT be * used to represent any printing US-ASCII character which can represent * itself. * * "&" is used to shift to modified BASE64 and "-" to shift back to * US-ASCII. There is no implicit shift from BASE64 to US-ASCII, and * null shifts ("-&" while in BASE64; note that "&-" while in US-ASCII * means "&") are not permitted. However, all names start in US-ASCII, * and MUST end in US-ASCII; that is, a name that ends with a non-ASCII * ISO-10646 character MUST end with a "-"). *********************************************************************** * * The purpose of all this is: 1) to keep all parts of IMAP messages 7-bit clean, * 2) to avoid giving special treatment to +, /, \, and ~, since these are * commonly used in mailbox names, and 3) to ensure there is only one * representation of any mailbox name (vanilla UTF-7 does allow multiple * representations of the same string, by Base64-encoding characters which * could have been included as ASCII literals.) * * RFC 2152 also applies, since it defines vanilla UTF-7 (minus IMAP modifications) * The following paragraph is notable: * *********************************************************************** * Unicode is encoded using Modified Base64 by first converting Unicode * 16-bit quantities to an octet stream (with the most significant octet first). * Surrogate pairs (UTF-16) are converted by treating each half of the pair as * a separate 16 bit quantity (i.e., no special treatment). Text with an odd * number of octets is ill-formed. ISO 10646 characters outside the range * addressable via surrogate pairs cannot be encoded. *********************************************************************** * * So after reversing the modified Base64 encoding on an encoded section, * the contents are interpreted as UTF-16BE. */ #include "mbfilter.h" #include "mbfilter_utf7imap.h" #include "utf7_helper.h" static int mbfl_filt_conv_wchar_utf7imap_flush(mbfl_convert_filter *filter); static int mbfl_filt_conv_utf7imap_wchar_flush(mbfl_convert_filter *filter); static size_t mb_utf7imap_to_wchar(unsigned char **in, size_t *in_len, uint32_t *buf, size_t bufsize, unsigned int *state); static void mb_wchar_to_utf7imap(uint32_t *in, size_t len, mb_convert_buf *buf, bool end); static bool mb_check_utf7imap(unsigned char *in, size_t in_len); static const char *mbfl_encoding_utf7imap_aliases[] = {"mUTF-7", NULL}; const mbfl_encoding mbfl_encoding_utf7imap = { mbfl_no_encoding_utf7imap, "UTF7-IMAP", NULL, mbfl_encoding_utf7imap_aliases, NULL, 0, &vtbl_utf7imap_wchar, &vtbl_wchar_utf7imap, mb_utf7imap_to_wchar, mb_wchar_to_utf7imap, mb_check_utf7imap, NULL, }; const struct mbfl_convert_vtbl vtbl_utf7imap_wchar = { mbfl_no_encoding_utf7imap, mbfl_no_encoding_wchar, mbfl_filt_conv_common_ctor, NULL, mbfl_filt_conv_utf7imap_wchar, mbfl_filt_conv_utf7imap_wchar_flush, NULL, }; const struct mbfl_convert_vtbl vtbl_wchar_utf7imap = { mbfl_no_encoding_wchar, mbfl_no_encoding_utf7imap, mbfl_filt_conv_common_ctor, NULL, mbfl_filt_conv_wchar_utf7imap, mbfl_filt_conv_wchar_utf7imap_flush, NULL, }; #define CK(statement) do { if ((statement) < 0) return (-1); } while (0) int mbfl_filt_conv_utf7imap_wchar(int c, mbfl_convert_filter *filter) { int s, n = -1; if (filter->status != 0) { /* Modified Base64 */ if (c >= 'A' && c <= 'Z') { n = c - 65; } else if (c >= 'a' && c <= 'z') { n = c - 71; } else if (c >= '0' && c <= '9') { n = c + 4; } else if (c == '+') { n = 62; } else if (c == ',') { n = 63; } if (n < 0 || n > 63) { if (c == '-') { if (filter->status == 1) { /* "&-" -> "&" */ filter->cache = filter->status = 0; CK((*filter->output_function)('&', filter->data)); } else if (filter->cache) { /* Base64-encoded section ended abruptly, with partially encoded characters, * or it could be that it ended on the first half of a surrogate pair */ filter->cache = filter->status = 0; CK((*filter->output_function)(MBFL_BAD_INPUT, filter->data)); } else { /* Base64-encoded section properly terminated by - */ filter->cache = filter->status = 0; } } else { /* illegal character */ filter->cache = filter->status = 0; CK((*filter->output_function)(MBFL_BAD_INPUT, filter->data)); } return 0; } } switch (filter->status) { /* directly encoded characters */ case 0: if (c == '&') { /* shift character */ filter->status++; } else if (c >= 0x20 && c <= 0x7E) { /* ASCII */ CK((*filter->output_function)(c, filter->data)); } else { /* illegal character */ CK((*filter->output_function)(MBFL_BAD_INPUT, filter->data)); } break; /* decode Modified Base64 */ case 1: case 2: filter->cache |= n << 10; filter->status = 3; break; case 3: filter->cache |= n << 4; filter->status = 4; break; case 4: s = ((n >> 2) & 0xf) | (filter->cache & 0xffff); n = (n & 0x3) << 14; filter->status = 5; if (s >= 0xd800 && s < 0xdc00) { /* 1st part of surrogate pair */ s = (((s & 0x3ff) << 16) + 0x400000) | n; filter->cache = s; } else if (s >= 0xdc00 && s < 0xe000) { /* 2nd part of surrogate pair */ if (filter->cache & 0xfff0000) { s &= 0x3ff; s |= (filter->cache & 0xfff0000) >> 6; filter->cache = n; CK((*filter->output_function)(s, filter->data)); } else { /* illegal character */ CK((*filter->output_function)(MBFL_BAD_INPUT, filter->data)); } } else { filter->cache = n; /* Characters which can be expressed as literal, ASCII characters * should not be Base64-encoded */ if (s < 0x20 || s > 0x7E || s == '&') { CK((*filter->output_function)(s, filter->data)); } else { CK((*filter->output_function)(MBFL_BAD_INPUT, filter->data)); } } break; case 5: filter->cache |= n << 8; filter->status = 6; break; case 6: filter->cache |= n << 2; filter->status = 7; break; case 7: s = ((n >> 4) & 0x3) | (filter->cache & 0xffff); n = (n & 0xf) << 12; filter->status = 8; if (s >= 0xd800 && s < 0xdc00) { s = (((s & 0x3ff) << 16) + 0x400000) | n; filter->cache = s; } else if (s >= 0xdc00 && s < 0xe000) { if (filter->cache & 0xfff0000) { s &= 0x3ff; s |= (filter->cache & 0xfff0000) >> 6; filter->cache = n; CK((*filter->output_function)(s, filter->data)); } else { /* illegal character */ CK((*filter->output_function)(MBFL_BAD_INPUT, filter->data)); } } else { filter->cache = n; /* Characters which can be expressed as literal, ASCII characters * should not be Base64-encoded */ if (s < 0x20 || s > 0x7E || s == '&') { CK((*filter->output_function)(s, filter->data)); } else { CK((*filter->output_function)(MBFL_BAD_INPUT, filter->data)); } } break; case 8: filter->cache |= n << 6; filter->status = 9; break; case 9: s = n | (filter->cache & 0xffff); filter->status = 2; if (s >= 0xd800 && s < 0xdc00) { s = (((s & 0x3ff) << 16) + 0x400000); filter->cache = s; } else if (s >= 0xdc00 && s < 0xe000) { if (filter->cache & 0xfff0000) { s &= 0x3ff; s |= (filter->cache & 0xfff0000) >> 6; filter->cache = 0; CK((*filter->output_function)(s, filter->data)); } else { /* illegal character */ CK((*filter->output_function)(MBFL_BAD_INPUT, filter->data)); } } else { filter->cache = 0; /* Characters which can be expressed as literal, ASCII characters * should not be Base64-encoded */ if (s < 0x20 || s > 0x7E || s == '&') { CK((*filter->output_function)(s, filter->data)); } else { CK((*filter->output_function)(MBFL_BAD_INPUT, filter->data)); } } break; EMPTY_SWITCH_DEFAULT_CASE(); } return 0; } static int mbfl_filt_conv_utf7imap_wchar_flush(mbfl_convert_filter *filter) { if (filter->status) { /* It is illegal for a UTF-7 IMAP string to end in a Base-64 encoded * section. It should always change back to ASCII before the end. */ (*filter->output_function)(MBFL_BAD_INPUT, filter->data); filter->status = 0; } if (filter->flush_function) { (*filter->flush_function)(filter->data); } return 0; } static const unsigned char mbfl_utf7imap_base64_table[] = { /* 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', */ 0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x4b,0x4c,0x4d, /* 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', */ 0x4e,0x4f,0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5a, /* 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', */ 0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x6b,0x6c,0x6d, /* 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', */ 0x6e,0x6f,0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a, /* '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', ',', '\0' */ 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x2b,0x2c,0x00 }; int mbfl_filt_conv_wchar_utf7imap(int c, mbfl_convert_filter *filter) { int n = 0, s; if (c == '&') { n = 1; } else if ((c >= 0x20 && c <= 0x7e) || c == 0) { n = 2; } else if (c >= 0 && c < MBFL_WCSPLANE_UCS2MAX) { ; } else if (c >= MBFL_WCSPLANE_SUPMIN && c < MBFL_WCSPLANE_SUPMAX) { s = ((c >> 10) - 0x40) | 0xd800; CK((*filter->filter_function)(s, filter)); s = (c & 0x3ff) | 0xdc00; CK((*filter->filter_function)(s, filter)); return 0; } else { CK(mbfl_filt_conv_illegal_output(c, filter)); return 0; } switch (filter->status) { case 0: if (n != 0) { /* directly encode characters */ CK((*filter->output_function)(c, filter->data)); if (n == 1) { CK((*filter->output_function)(0x2d, filter->data)); /* '-' */ } } else { /* Modified Base64 */ CK((*filter->output_function)(0x26, filter->data)); /* '&' */ filter->status = 1; filter->cache = c; } break; /* encode Modified Base64 */ case 1: s = filter->cache; CK((*filter->output_function)(mbfl_utf7imap_base64_table[(s >> 10) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(s >> 4) & 0x3f], filter->data)); if (n != 0) { CK((*filter->output_function)(mbfl_utf7imap_base64_table[(s << 2) & 0x3c], filter->data)); CK((*filter->output_function)('-', filter->data)); CK((*filter->output_function)(c, filter->data)); if (n == 1) { CK((*filter->output_function)('-', filter->data)); } filter->status = 0; } else { filter->status = 2; filter->cache = ((s & 0xf) << 16) | c; } break; case 2: s = filter->cache; CK((*filter->output_function)(mbfl_utf7imap_base64_table[(s >> 14) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(s >> 8) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(s >> 2) & 0x3f], filter->data)); if (n != 0) { CK((*filter->output_function)(mbfl_utf7imap_base64_table[(s << 4) & 0x30], filter->data)); CK((*filter->output_function)('-', filter->data)); CK((*filter->output_function)(c, filter->data)); if (n == 1) { CK((*filter->output_function)('-', filter->data)); } filter->status = 0; } else { filter->status = 3; filter->cache = ((s & 0x3) << 16) | c; } break; case 3: s = filter->cache; CK((*filter->output_function)(mbfl_utf7imap_base64_table[(s >> 12) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(s >> 6) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[s & 0x3f], filter->data)); if (n != 0) { CK((*filter->output_function)('-', filter->data)); CK((*filter->output_function)(c, filter->data)); if (n == 1) { CK((*filter->output_function)('-', filter->data)); } filter->status = 0; } else { filter->status = 1; filter->cache = c; } break; EMPTY_SWITCH_DEFAULT_CASE(); } return 0; } static int mbfl_filt_conv_wchar_utf7imap_flush(mbfl_convert_filter *filter) { int status = filter->status, cache = filter->cache; filter->status = filter->cache = 0; /* flush fragments */ switch (status) { case 1: CK((*filter->output_function)(mbfl_utf7imap_base64_table[(cache >> 10) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(cache >> 4) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(cache << 2) & 0x3c], filter->data)); CK((*filter->output_function)('-', filter->data)); break; case 2: CK((*filter->output_function)(mbfl_utf7imap_base64_table[(cache >> 14) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(cache >> 8) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(cache >> 2) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(cache << 4) & 0x30], filter->data)); CK((*filter->output_function)('-', filter->data)); break; case 3: CK((*filter->output_function)(mbfl_utf7imap_base64_table[(cache >> 12) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[(cache >> 6) & 0x3f], filter->data)); CK((*filter->output_function)(mbfl_utf7imap_base64_table[cache & 0x3f], filter->data)); CK((*filter->output_function)('-', filter->data)); break; } return 0; } static inline bool is_base64_end(unsigned char c) { return c >= DASH; } static unsigned char decode_base64(unsigned char c) { if (c >= 'A' && c <= 'Z') { return c - 65; } else if (c >= 'a' && c <= 'z') { return c - 71; } else if (c >= '0' && c <= '9') { return c + 4; } else if (c == '+') { return 62; } else if (c == ',') { return 63; } else if (c == '-') { return DASH; } return ILLEGAL; } static uint32_t* handle_utf16_cp(uint16_t cp, uint32_t *out, uint16_t *surrogate1) { retry: if (*surrogate1) { if (cp >= 0xDC00 && cp <= 0xDFFF) { *out++ = ((*surrogate1 & 0x3FF) << 10) + (cp & 0x3FF) + 0x10000; *surrogate1 = 0; } else { *out++ = MBFL_BAD_INPUT; *surrogate1 = 0; goto retry; } } else if (cp >= 0xD800 && cp <= 0xDBFF) { *surrogate1 = cp; } else if (cp >= 0xDC00 && cp <= 0xDFFF) { /* 2nd part of surrogate pair came unexpectedly */ *out++ = MBFL_BAD_INPUT; } else if (cp >= 0x20 && cp <= 0x7E && cp != '&') { *out++ = MBFL_BAD_INPUT; } else { *out++ = cp; } return out; } static uint32_t* handle_base64_end(unsigned char n, uint32_t *out, bool *base64, bool abrupt, uint16_t *surrogate1) { if (abrupt || n == ILLEGAL || *surrogate1) { *out++ = MBFL_BAD_INPUT; *surrogate1 = 0; } *base64 = false; return out; } static size_t mb_utf7imap_to_wchar(unsigned char **in, size_t *in_len, uint32_t *buf, size_t bufsize, unsigned int *state) { ZEND_ASSERT(bufsize >= 5); /* This function will infinite-loop if called with a tiny output buffer */ /* Why does this require a minimum output buffer size of 5? * See comment in mb_utf7_to_wchar; the worst case for this function is similar, * though not exactly the same. */ unsigned char *p = *in, *e = p + *in_len; /* Always leave one empty space in output buffer in case the string ends while * in Base64 mode and we need to emit an error marker */ uint32_t *out = buf, *limit = buf + bufsize - 1; bool base64 = *state & 1; uint16_t surrogate1 = (*state >> 1); /* First half of a surrogate pair */ while (p < e && out < limit) { if (base64) { /* Base64 section */ if ((limit - out) < 4) { break; } unsigned char n1 = decode_base64(*p++); if (is_base64_end(n1)) { out = handle_base64_end(n1, out, &base64, false, &surrogate1); continue; } else if (p == e) { out = handle_base64_end(n1, out, &base64, true, &surrogate1); continue; } unsigned char n2 = decode_base64(*p++); if (is_base64_end(n2) || p == e) { out = handle_base64_end(n2, out, &base64, true, &surrogate1); continue; } unsigned char n3 = decode_base64(*p++); if (is_base64_end(n3)) { out = handle_base64_end(n3, out, &base64, true, &surrogate1); continue; } out = handle_utf16_cp((n1 << 10) | (n2 << 4) | ((n3 & 0x3C) >> 2), out, &surrogate1); if (p == e) { /* It is an error if trailing padding bits are not zeroes or if we were * expecting the 2nd part of a surrogate pair when Base64 section ends */ if ((n3 & 0x3) || surrogate1) *out++ = MBFL_BAD_INPUT; break; } unsigned char n4 = decode_base64(*p++); if (is_base64_end(n4)) { out = handle_base64_end(n4, out, &base64, n3 & 0x3, &surrogate1); continue; } else if (p == e) { out = handle_base64_end(n4, out, &base64, true, &surrogate1); continue; } unsigned char n5 = decode_base64(*p++); if (is_base64_end(n5) || p == e) { out = handle_base64_end(n5, out, &base64, true, &surrogate1); continue; } unsigned char n6 = decode_base64(*p++); if (is_base64_end(n6)) { out = handle_base64_end(n6, out, &base64, true, &surrogate1); continue; } out = handle_utf16_cp((n3 << 14) | (n4 << 8) | (n5 << 2) | ((n6 & 0x30) >> 4), out, &surrogate1); if (p == e) { if ((n6 & 0xF) || surrogate1) *out++ = MBFL_BAD_INPUT; break; } unsigned char n7 = decode_base64(*p++); if (is_base64_end(n7)) { out = handle_base64_end(n7, out, &base64, n6 & 0xF, &surrogate1); continue; } else if (p == e) { out = handle_base64_end(n7, out, &base64, true, &surrogate1); continue; } unsigned char n8 = decode_base64(*p++); if (is_base64_end(n8)) { out = handle_base64_end(n8, out, &base64, true, &surrogate1); continue; } out = handle_utf16_cp((n6 << 12) | (n7 << 6) | n8, out, &surrogate1); } else { unsigned char c = *p++; if (c == '&') { if (p < e && *p == '-') { *out++ = '&'; p++; } else { base64 = true; } } else if (c >= 0x20 && c <= 0x7E) { *out++ = c; } else { *out++ = MBFL_BAD_INPUT; } } } if (p == e && base64) { /* UTF7-IMAP doesn't allow strings to end in Base64 mode * One space in output buffer was reserved just for this */ ZEND_ASSERT(out < limit); *out++ = MBFL_BAD_INPUT; } *state = (surrogate1 << 1) | base64; *in_len = e - p; *in = p; return out - buf; } #define SAVE_CONVERSION_STATE() buf->state = (cache << 4) | (nbits << 1) | base64 #define RESTORE_CONVERSION_STATE() base64 = (buf->state & 1); nbits = (buf->state >> 1) & 0x7; cache = (buf->state >> 4) static const unsigned char mbfl_base64_table[] = { /* 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', */ 0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x4b,0x4c,0x4d, /* 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', */ 0x4e,0x4f,0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5a, /* 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', */ 0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x6b,0x6c,0x6d, /* 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', */ 0x6e,0x6f,0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a, /* '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', ',', '\0' */ 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x2b,0x2c,0x00 }; static void mb_wchar_to_utf7imap(uint32_t *in, size_t len, mb_convert_buf *buf, bool end) { unsigned char *out, *limit; MB_CONVERT_BUF_LOAD(buf, out, limit); MB_CONVERT_BUF_ENSURE(buf, out, limit, len); bool base64; unsigned char nbits, cache; /* `nbits` is the number of cached bits; either 0, 2, or 4 */ RESTORE_CONVERSION_STATE(); while (len--) { uint32_t w = *in++; if (base64) { if (w >= 0x20 && w <= 0x7E) { /* End of Base64 section. Drain buffered bits (if any), close Base64 section * Leave enough space in the output buffer such that even if the remainder of * the input string is ASCII, we can output the whole thing without having to * check for output buffer space again */ base64 = false; in--; len++; /* Unconsume codepoint; it will be handled by 'ASCII section' code below */ MB_CONVERT_BUF_ENSURE(buf, out, limit, len + 2); if (nbits) { out = mb_convert_buf_add(out, mbfl_base64_table[(cache << (6 - nbits)) & 0x3F]); } nbits = cache = 0; out = mb_convert_buf_add(out, '-'); } else if (w >= MBFL_WCSPLANE_UTF32MAX) { /* Make recursive call to add an error marker character */ SAVE_CONVERSION_STATE(); MB_CONVERT_ERROR(buf, out, limit, w, mb_wchar_to_utf7imap); MB_CONVERT_BUF_ENSURE(buf, out, limit, len); RESTORE_CONVERSION_STATE(); } else { /* Encode codepoint, preceded by any cached bits, as Base64 * Make enough space in the output buffer to hold both any bytes that * we emit right here, plus any finishing byte which might need to * be emitted if the input string ends abruptly */ uint64_t bits; if (w >= MBFL_WCSPLANE_SUPMIN) { /* Must use surrogate pair */ MB_CONVERT_BUF_ENSURE(buf, out, limit, 7); w -= 0x10000; bits = ((uint64_t)cache << 32) | 0xD800DC00L | ((w & 0xFFC00) << 6) | (w & 0x3FF); nbits += 32; } else { MB_CONVERT_BUF_ENSURE(buf, out, limit, 4); bits = (cache << 16) | w; nbits += 16; } while (nbits >= 6) { out = mb_convert_buf_add(out, mbfl_base64_table[(bits >> (nbits - 6)) & 0x3F]); nbits -= 6; } cache = bits; } } else { /* ASCII section */ if (w == '&') { MB_CONVERT_BUF_ENSURE(buf, out, limit, len + 2); out = mb_convert_buf_add2(out, '&', '-'); } else if (w >= 0x20 && w <= 0x7E) { out = mb_convert_buf_add(out, w); } else if (w >= MBFL_WCSPLANE_UTF32MAX) { buf->state = 0; MB_CONVERT_ERROR(buf, out, limit, w, mb_wchar_to_utf7imap); MB_CONVERT_BUF_ENSURE(buf, out, limit, len); RESTORE_CONVERSION_STATE(); } else { out = mb_convert_buf_add(out, '&'); base64 = true; in--; len++; /* Unconsume codepoint; it will be handled by Base64 code above */ } } } if (end) { if (nbits) { out = mb_convert_buf_add(out, mbfl_base64_table[(cache << (6 - nbits)) & 0x3F]); } if (base64) { MB_CONVERT_BUF_ENSURE(buf, out, limit, 1); out = mb_convert_buf_add(out, '-'); } } else { SAVE_CONVERSION_STATE(); } MB_CONVERT_BUF_STORE(buf, out, limit); } static bool is_utf16_cp_valid(uint16_t cp, bool is_surrogate) { if (is_surrogate) { return cp >= 0xDC00 && cp <= 0xDFFF; } else if (cp >= 0xDC00 && cp <= 0xDFFF) { /* 2nd part of surrogate pair came unexpectedly */ return false; } else if (cp >= 0x20 && cp <= 0x7E && cp != '&') { return false; } return true; } static bool mb_check_utf7imap(unsigned char *in, size_t in_len) { unsigned char *p = in, *e = p + in_len; bool base64 = false; bool is_surrogate = false; while (p < e) { if (base64) { /* Base64 section */ unsigned char n1 = decode_base64(*p++); if (is_base64_end(n1)) { if (!is_base64_end_valid(n1, false, is_surrogate)) { return false; } base64 = false; continue; } else if (p == e) { return false; } unsigned char n2 = decode_base64(*p++); if (is_base64_end(n2) || p == e) { return false; } unsigned char n3 = decode_base64(*p++); if (is_base64_end(n3)) { return false; } uint16_t cp1 = (n1 << 10) | (n2 << 4) | ((n3 & 0x3C) >> 2); if (!is_utf16_cp_valid(cp1, is_surrogate)) { return false; } is_surrogate = has_surrogate(cp1, is_surrogate); if (p == e) { return false; } unsigned char n4 = decode_base64(*p++); if (is_base64_end(n4)) { if (!is_base64_end_valid(n4, n3 & 0x3, is_surrogate)) { return false; } base64 = false; continue; } else if (p == e) { return false; } unsigned char n5 = decode_base64(*p++); if (is_base64_end(n5) || p == e) { return false; } unsigned char n6 = decode_base64(*p++); if (is_base64_end(n6)) { return false; } uint16_t cp2 = (n3 << 14) | (n4 << 8) | (n5 << 2) | ((n6 & 0x30) >> 4); if (!is_utf16_cp_valid(cp2, is_surrogate)) { return false; } is_surrogate = has_surrogate(cp2, is_surrogate); if (p == e) { return false; } unsigned char n7 = decode_base64(*p++); if (is_base64_end(n7)) { if (!is_base64_end_valid(n7, n6 & 0xF, is_surrogate)) { return false; } base64 = false; continue; } else if (p == e) { return false; } unsigned char n8 = decode_base64(*p++); if (is_base64_end(n8)) { return false; } uint16_t cp3 = (n6 << 12) | (n7 << 6) | n8; if (!is_utf16_cp_valid(cp3, is_surrogate)) { return false; } is_surrogate = has_surrogate(cp3, is_surrogate); } else { /* ASCII text section */ unsigned char c = *p++; if (c == '&') { if (p == e) { return false; } unsigned char n = decode_base64(*p); if (n == DASH) { p++; } else if (n == ILLEGAL) { return false; } else { base64 = true; } } else if (c >= 0x20 && c <= 0x7E) { continue; } else { return false; } } } return !base64; }