Mercurial > vim
annotate src/crypt_zip.c @ 29725:21638dfef502
Added tag v9.0.0202 for changeset 66f9877b8aaba1a9858f91fdf1392450ba553749
| author | Bram Moolenaar <Bram@vim.org> |
|---|---|
| date | Sat, 13 Aug 2022 22:45:04 +0200 |
| parents | 7e9e53a0368f |
| children | 50555279168b |
| rev | line source |
|---|---|
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commit https://github.com/vim/vim/commit/edf3f97ae2af024708ebb4ac614227327033ca47
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1 /* vi:set ts=8 sts=4 sw=4 noet: |
| 6122 | 2 * |
| 3 * VIM - Vi IMproved by Bram Moolenaar | |
| 4 * | |
| 5 * Do ":help uganda" in Vim to read copying and usage conditions. | |
| 6 * Do ":help credits" in Vim to see a list of people who contributed. | |
| 7 * See README.txt for an overview of the Vim source code. | |
| 8 */ | |
| 9 | |
| 10 /* | |
| 11 * crypt_zip.c: Zip encryption support. | |
| 12 */ | |
| 13 #include "vim.h" | |
| 14 | |
| 15 #if defined(FEAT_CRYPT) || defined(PROTO) | |
| 16 /* | |
| 17 * Optional encryption support. | |
| 18 * Mohsin Ahmed, mosh@sasi.com, 98-09-24 | |
| 19 * Based on zip/crypt sources. | |
| 20 * | |
| 21 * NOTE FOR USA: Since 2000 exporting this code from the USA is allowed to | |
| 22 * most countries. There are a few exceptions, but that still should not be a | |
| 23 * problem since this code was originally created in Europe and India. | |
| 24 */ | |
| 25 | |
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26 // Need a type that should be 32 bits. 64 also works but wastes space. |
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27 typedef unsigned int u32_T; // int is at least 32 bits |
| 6122 | 28 |
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29 // The state of encryption, referenced by cryptstate_T. |
| 6122 | 30 typedef struct { |
| 31 u32_T keys[3]; | |
| 32 } zip_state_T; | |
| 33 | |
| 34 | |
| 35 static u32_T crc_32_table[256]; | |
| 36 | |
| 37 /* | |
| 38 * Fill the CRC table, if not done already. | |
| 39 */ | |
| 40 static void | |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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41 make_crc_tab(void) |
| 6122 | 42 { |
| 43 u32_T s, t, v; | |
| 44 static int done = FALSE; | |
| 45 | |
| 46 if (done) | |
| 47 return; | |
| 48 for (t = 0; t < 256; t++) | |
| 49 { | |
| 50 v = t; | |
| 51 for (s = 0; s < 8; s++) | |
| 52 v = (v >> 1) ^ ((v & 1) * (u32_T)0xedb88320L); | |
| 53 crc_32_table[t] = v; | |
| 54 } | |
| 55 done = TRUE; | |
| 56 } | |
| 57 | |
| 58 #define CRC32(c, b) (crc_32_table[((int)(c) ^ (b)) & 0xff] ^ ((c) >> 8)) | |
| 59 | |
| 60 /* | |
| 61 * Return the next byte in the pseudo-random sequence. | |
| 62 */ | |
| 63 #define DECRYPT_BYTE_ZIP(keys, t) { \ | |
| 64 short_u temp = (short_u)keys[2] | 2; \ | |
| 65 t = (int)(((unsigned)(temp * (temp ^ 1U)) >> 8) & 0xff); \ | |
| 66 } | |
| 67 | |
| 68 /* | |
| 69 * Update the encryption keys with the next byte of plain text. | |
| 70 */ | |
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71 #define UPDATE_KEYS_ZIP(keys, c) do { \ |
| 6122 | 72 keys[0] = CRC32(keys[0], (c)); \ |
| 73 keys[1] += keys[0] & 0xff; \ | |
| 74 keys[1] = keys[1] * 134775813L + 1; \ | |
| 75 keys[2] = CRC32(keys[2], (int)(keys[1] >> 24)); \ | |
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76 } while (0) |
| 6122 | 77 |
| 78 /* | |
| 79 * Initialize for encryption/decryption. | |
| 80 */ | |
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81 int |
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82 crypt_zip_init( |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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83 cryptstate_T *state, |
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84 char_u *key, |
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85 char_u *salt UNUSED, |
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86 int salt_len UNUSED, |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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87 char_u *seed UNUSED, |
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88 int seed_len UNUSED) |
| 6122 | 89 { |
| 90 char_u *p; | |
| 91 zip_state_T *zs; | |
| 92 | |
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93 zs = ALLOC_ONE(zip_state_T); |
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94 if (zs == NULL) |
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95 return FAIL; |
| 6122 | 96 state->method_state = zs; |
| 97 | |
| 98 make_crc_tab(); | |
| 99 zs->keys[0] = 305419896L; | |
| 100 zs->keys[1] = 591751049L; | |
| 101 zs->keys[2] = 878082192L; | |
| 102 for (p = key; *p != NUL; ++p) | |
| 103 UPDATE_KEYS_ZIP(zs->keys, (int)*p); | |
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104 |
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105 return OK; |
| 6122 | 106 } |
| 107 | |
| 108 /* | |
| 109 * Encrypt "from[len]" into "to[len]". | |
| 110 * "from" and "to" can be equal to encrypt in place. | |
| 111 */ | |
| 112 void | |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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113 crypt_zip_encode( |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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parents:
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114 cryptstate_T *state, |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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115 char_u *from, |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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116 size_t len, |
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117 char_u *to, |
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118 int last UNUSED) |
| 6122 | 119 { |
| 120 zip_state_T *zs = state->method_state; | |
| 121 size_t i; | |
| 122 int ztemp, t; | |
| 123 | |
| 124 for (i = 0; i < len; ++i) | |
| 125 { | |
| 126 ztemp = from[i]; | |
| 127 DECRYPT_BYTE_ZIP(zs->keys, t); | |
| 128 UPDATE_KEYS_ZIP(zs->keys, ztemp); | |
| 129 to[i] = t ^ ztemp; | |
| 130 } | |
| 131 } | |
| 132 | |
| 133 /* | |
| 134 * Decrypt "from[len]" into "to[len]". | |
| 135 */ | |
| 136 void | |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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137 crypt_zip_decode( |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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parents:
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138 cryptstate_T *state, |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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139 char_u *from, |
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commit https://github.com/vim/vim/commit/7454a06e2642d2b37afad1c5e71cec68081ca4ff
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140 size_t len, |
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141 char_u *to, |
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142 int last UNUSED) |
| 6122 | 143 { |
| 144 zip_state_T *zs = state->method_state; | |
| 145 size_t i; | |
| 146 short_u temp; | |
| 147 | |
| 148 for (i = 0; i < len; ++i) | |
| 149 { | |
| 150 temp = (short_u)zs->keys[2] | 2; | |
| 151 temp = (int)(((unsigned)(temp * (temp ^ 1U)) >> 8) & 0xff); | |
| 152 UPDATE_KEYS_ZIP(zs->keys, to[i] = from[i] ^ temp); | |
| 153 } | |
| 154 } | |
| 155 | |
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156 #endif // FEAT_CRYPT |