| File: | builds/wireshark/wireshark/epan/tvbuff_lznt1.c |
| Warning: | line 155, column 7 Potential leak of memory pointed to by 'p' |
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| 1 | /* | |||
| 2 | * Decompression code for LZNT1. This encoding is used by | |||
| 3 | * Microsoft in various file formats and protocols including SMB3. | |||
| 4 | * | |||
| 5 | * See MS-XCA. | |||
| 6 | * | |||
| 7 | * Copyright (C) 2019 Aurélien Aptel | |||
| 8 | * | |||
| 9 | * Wireshark - Network traffic analyzer | |||
| 10 | * By Gerald Combs <[email protected]> | |||
| 11 | * Copyright 1998 Gerald Combs | |||
| 12 | * | |||
| 13 | * SPDX-License-Identifier: GPL-2.0-or-later | |||
| 14 | */ | |||
| 15 | ||||
| 16 | #include <glib.h> | |||
| 17 | #include <epan/exceptions.h> | |||
| 18 | #include <epan/tvbuff.h> | |||
| 19 | #include <epan/wmem_scopes.h> | |||
| 20 | ||||
| 21 | #define MAX_INPUT_SIZE(16*1024*1024) (16*1024*1024) /* 16MB */ | |||
| 22 | ||||
| 23 | static bool_Bool | |||
| 24 | uncompress_chunk(tvbuff_t *tvb, int offset, unsigned in_size, wmem_array_t *obuf) | |||
| 25 | { | |||
| 26 | unsigned in_off = 0, out_off = 0, out_start = 0; | |||
| 27 | uint8_t flags; | |||
| 28 | unsigned i, j, pos; | |||
| 29 | uint8_t val; | |||
| 30 | ||||
| 31 | out_start = wmem_array_get_count(obuf); | |||
| 32 | ||||
| 33 | while (in_off < in_size) { | |||
| 34 | flags = tvb_get_uint8(tvb, offset+in_off); | |||
| 35 | in_off++; | |||
| 36 | for (i = 0; i < 8; i++) { | |||
| 37 | if (0 == ((flags>>i)&1)) { | |||
| 38 | val = tvb_get_uint8(tvb, offset+in_off); | |||
| 39 | in_off++; | |||
| 40 | wmem_array_append_one(obuf, val)wmem_array_append((obuf), &(val), 1); | |||
| 41 | out_off++; | |||
| 42 | } else { | |||
| 43 | unsigned f, l_mask = 0x0FFF, o_shift = 12; | |||
| 44 | unsigned match_len, match_off; | |||
| 45 | ||||
| 46 | f = tvb_get_letohs(tvb, offset+in_off); | |||
| 47 | in_off += 2; | |||
| 48 | /* Let M be the largest value in [4...12] such | |||
| 49 | * that 2^{M-1} < U, or 4 if there is no such. | |||
| 50 | * Equivalently, we can repeatedly divide U by | |||
| 51 | * 2, but we need to subtract 1 first and test | |||
| 52 | * vs a weak inequality in order to account for | |||
| 53 | * truncation. (But don't overflow at U == 0.) | |||
| 54 | */ | |||
| 55 | if (out_off > 0) { | |||
| 56 | pos = out_off-1; | |||
| 57 | while (pos >= 0x10) { | |||
| 58 | l_mask >>= 1; | |||
| 59 | o_shift -= 1; | |||
| 60 | pos >>= 1; | |||
| 61 | } | |||
| 62 | } | |||
| 63 | ||||
| 64 | match_len = (f & l_mask) + 3; | |||
| 65 | match_off = (f >> o_shift) + 1; | |||
| 66 | /* out_off only increases, only test once. */ | |||
| 67 | if (match_off > out_start + out_off) | |||
| 68 | return false0; | |||
| 69 | /* Must call grow first, to realloc the array | |||
| 70 | * if needed. */ | |||
| 71 | if (!wmem_array_grow(obuf, match_len)) | |||
| 72 | return false0; | |||
| 73 | uint8_t *src; | |||
| 74 | for (j = 0; j < match_len / match_off; j++) { | |||
| 75 | src = wmem_array_index(obuf, out_start + out_off - match_off); | |||
| 76 | wmem_array_append(obuf, src, match_off); | |||
| 77 | out_off += match_off; | |||
| 78 | } | |||
| 79 | for (j *= match_off; j < match_len; j++) { | |||
| 80 | src = wmem_array_index(obuf, out_start + out_off - match_off); | |||
| 81 | wmem_array_append(obuf, src, 1); | |||
| 82 | out_off++; | |||
| 83 | } | |||
| 84 | } | |||
| 85 | if (in_off == in_size) { | |||
| 86 | goto out; | |||
| 87 | } | |||
| 88 | } | |||
| 89 | } | |||
| 90 | out: | |||
| 91 | return true1; | |||
| 92 | } | |||
| 93 | ||||
| 94 | static bool_Bool | |||
| 95 | do_uncompress(tvbuff_t *tvb, int offset, int in_size, wmem_array_t *obuf) | |||
| 96 | { | |||
| 97 | int in_off = 0; | |||
| 98 | uint32_t header, length, i; | |||
| 99 | bool_Bool ok; | |||
| 100 | ||||
| 101 | if (!tvb) | |||
| 102 | return false0; | |||
| 103 | ||||
| 104 | if (!in_size || in_size > MAX_INPUT_SIZE(16*1024*1024)) | |||
| 105 | return false0; | |||
| 106 | ||||
| 107 | while (in_off < in_size) { | |||
| 108 | header = tvb_get_letohs(tvb, offset+in_off); | |||
| 109 | in_off += 2; | |||
| 110 | length = (header & 0x0FFF) + 1; | |||
| 111 | if (!(header & 0x8000)) { | |||
| 112 | for (i = 0; i < length; i++) { | |||
| 113 | uint8_t v = tvb_get_uint8(tvb, offset+in_off); | |||
| 114 | wmem_array_append_one(obuf, v)wmem_array_append((obuf), &(v), 1); | |||
| 115 | in_off++; | |||
| 116 | } | |||
| 117 | } else { | |||
| 118 | ok = uncompress_chunk(tvb, offset + in_off, length, obuf); | |||
| 119 | if (!ok) | |||
| 120 | return false0; | |||
| 121 | in_off += length; | |||
| 122 | } | |||
| 123 | } | |||
| 124 | return true1; | |||
| 125 | } | |||
| 126 | ||||
| 127 | tvbuff_t * | |||
| 128 | tvb_uncompress_lznt1(tvbuff_t *tvb, const unsigned offset, unsigned in_size) | |||
| 129 | { | |||
| 130 | volatile bool_Bool ok = false0; | |||
| 131 | wmem_allocator_t *pool; | |||
| 132 | wmem_array_t *obuf; | |||
| 133 | tvbuff_t *out; | |||
| 134 | ||||
| 135 | pool = wmem_allocator_new(WMEM_ALLOCATOR_SIMPLE); | |||
| 136 | obuf = wmem_array_sized_new(pool, 1, in_size*2); | |||
| 137 | ||||
| 138 | TRY{ except_t *volatile exc; volatile int except_state = 0; static const except_id_t catch_spec[] = { { 1, 0 } }; { struct except_stacknode except_sn; struct except_catch except_ch; except_setup_try(& except_sn, &except_ch, catch_spec, 1); if (_setjmp (except_ch .except_jmp)) *(&exc) = &except_ch.except_obj; else * (&exc) = 0; if(except_state & 1) except_state |= 2; except_state &= ~1; if (except_state == 0 && exc == 0) { | |||
| 139 | ok = do_uncompress(tvb, offset, in_size, obuf); | |||
| 140 | } CATCH_ALLif (except_state == 0 && exc != 0 && (except_state |=1)) { | |||
| 141 | ok = false0; | |||
| 142 | } | |||
| 143 | ENDTRYif(!(except_state&1) && exc != 0) except_rethrow( exc); except_free(except_ch.except_obj.except_dyndata); except_pop (); };}; | |||
| 144 | ||||
| 145 | if (ok) { | |||
| 146 | /* | |||
| 147 | * Cannot pass a tvb free callback that frees the wmem | |||
| 148 | * pool, so we make an extra copy that uses bare | |||
| 149 | * pointers. This could be optimized if tvb API had a | |||
| 150 | * free pool callback of some sort. | |||
| 151 | */ | |||
| 152 | unsigned size = wmem_array_get_count(obuf); | |||
| 153 | uint8_t *p = (uint8_t *)g_malloc(size); | |||
| 154 | memcpy(p, wmem_array_get_raw(obuf), size); | |||
| 155 | out = tvb_new_real_data(p, size, size); | |||
| ||||
| 156 | tvb_set_free_cb(out, g_free); | |||
| 157 | } else { | |||
| 158 | out = NULL((void*)0); | |||
| 159 | } | |||
| 160 | ||||
| 161 | wmem_destroy_allocator(pool); | |||
| 162 | ||||
| 163 | return out; | |||
| 164 | } | |||
| 165 | ||||
| 166 | tvbuff_t * | |||
| 167 | tvb_child_uncompress_lznt1(tvbuff_t *parent, tvbuff_t *tvb, const unsigned offset, unsigned in_size) | |||
| 168 | { | |||
| 169 | tvbuff_t *new_tvb = tvb_uncompress_lznt1(tvb, offset, in_size); | |||
| ||||
| 170 | if (new_tvb) | |||
| 171 | tvb_set_child_real_data_tvbuff(parent, new_tvb); | |||
| 172 | return new_tvb; | |||
| 173 | } | |||
| 174 | ||||
| 175 | /* | |||
| 176 | * Editor modelines - https://www.wireshark.org/tools/modelines.html | |||
| 177 | * | |||
| 178 | * Local variables: | |||
| 179 | * c-basic-offset: 8 | |||
| 180 | * tab-width: 8 | |||
| 181 | * indent-tabs-mode: t | |||
| 182 | * End: | |||
| 183 | * | |||
| 184 | * vi: set shiftwidth=8 tabstop=8 noexpandtab: | |||
| 185 | * :indentSize=8:tabSize=8:noTabs=false: | |||
| 186 | */ |