338 lines
12 KiB
C
338 lines
12 KiB
C
/*
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* Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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* Copyright (C) 2007-2013 Sourcefire, Inc.
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*
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* Authors: Tomasz Kojm
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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#ifndef __MATCHER_H
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#define __MATCHER_H
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#include <sys/types.h>
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#include "clamav.h"
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#include "filetypes.h"
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#include "others.h"
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#include "execs.h"
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struct cli_target_info {
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off_t fsize;
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struct cli_exe_info exeinfo;
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int status; /* 0 == not initialised, 1 == initialised OK, -1 == error */
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};
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/**
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* Initialize a struct cli_target_info so that it's ready to have its exeinfo
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* populated by the call to cli_targetinfo and/or destroyed by
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* cli_targetinfo_destroy.
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*
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* @param info a pointer to the struct cli_target_info to initialize
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*/
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void cli_targetinfo_init(struct cli_target_info *info);
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/**
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* Free resources associated with a struct cli_target_info initialized
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* via cli_targetinfo_init
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*
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* @param info a pointer to the struct cli_target_info to destroy
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*/
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void cli_targetinfo_destroy(struct cli_target_info *info);
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#include "matcher-ac.h"
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#include "matcher-bm.h"
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#include "matcher-hash.h"
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#include "matcher-pcre.h"
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#include "matcher-byte-comp.h"
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#include "regex_pcre.h"
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#include "fmap.h"
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#include "mpool.h"
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// clang-format off
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#define CLI_MATCH_METADATA 0xff00
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#define CLI_MATCH_WILDCARD 0x0f00
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#define CLI_MATCH_CHAR 0x0000
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#define CLI_MATCH_NOCASE 0x1000
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#define CLI_MATCH_IGNORE 0x0100
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#define CLI_MATCH_SPECIAL 0x0200
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#define CLI_MATCH_NIBBLE_HIGH 0x0300
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#define CLI_MATCH_NIBBLE_LOW 0x0400
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typedef enum tdb_type {
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CLI_TDB_UINT,
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CLI_TDB_RANGE,
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CLI_TDB_STR,
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CLI_TDB_RANGE2,
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CLI_TDB_FTYPE,
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CLI_TDB_FTYPE_EXPR
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} tdb_type_t;
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struct cli_lsig_tdb {
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uint32_t *val, *range;
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char *str;
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tdb_type_t cnt[3];
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uint32_t subsigs;
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const uint32_t *target;
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const uint32_t *engine, *nos, *ep, *filesize;
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const uint32_t *container, *handlertype;
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const uint32_t *intermediates;
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/*
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const uint32_t *sectoff, *sectrva, *sectvsz, *sectraw, *sectrsz,
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*secturva, *sectuvsz, *secturaw, *sectursz;
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*/
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const char *icongrp1, *icongrp2;
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uint32_t *macro_ptids;
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#ifdef USE_MPOOL
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mpool_t *mempool;
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#endif
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};
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// clang-format on
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#define CLI_LSIG_FLAG_PRIVATE 0x01
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typedef enum lsig_type {
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CLI_LSIG_NORMAL,
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CLI_YARA_NORMAL,
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CLI_YARA_OFFSET
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} lsig_type_t;
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struct cli_bc;
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struct cli_ac_lsig {
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uint32_t id;
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unsigned bc_idx;
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lsig_type_t type;
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uint8_t flag;
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union {
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char *logic;
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uint8_t *code_start;
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} u;
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const char *virname;
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struct cli_lsig_tdb tdb;
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};
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struct cli_matcher {
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unsigned int type;
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/* Extended Boyer-Moore */
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uint8_t *bm_shift;
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struct cli_bm_patt **bm_suffix, **bm_pattab;
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uint32_t *soff, soff_len; /* for PE section sigs */
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uint32_t bm_offmode, bm_patterns, bm_reloff_num, bm_absoff_num;
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/* HASH */
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struct cli_hash_patt hm;
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struct cli_hash_wild hwild;
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/* Extended Aho-Corasick */
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uint32_t ac_partsigs, ac_nodes, ac_lists, ac_patterns, ac_lsigs;
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struct cli_ac_lsig **ac_lsigtable;
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struct cli_ac_node *ac_root, **ac_nodetable;
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struct cli_ac_list **ac_listtable;
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struct cli_ac_patt **ac_pattable;
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struct cli_ac_patt **ac_reloff;
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uint32_t ac_reloff_num, ac_absoff_num;
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uint8_t ac_mindepth, ac_maxdepth;
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struct filter *filter;
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uint16_t maxpatlen;
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uint8_t ac_only;
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/* Perl-Compiled Regular Expressions */
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#if HAVE_PCRE
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uint32_t pcre_metas;
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struct cli_pcre_meta **pcre_metatable;
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uint32_t pcre_reloff_num, pcre_absoff_num;
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#endif
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/* Byte Compare */
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uint32_t bcomp_metas;
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struct cli_bcomp_meta **bcomp_metatable;
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/* Bytecode Tracker */
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uint32_t linked_bcs;
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#ifdef USE_MPOOL
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mpool_t *mempool;
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#endif
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};
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struct cli_cdb {
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char *virname; /* virus name */
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cli_file_t ctype; /* container type */
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regex_t name; /* filename regex */
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size_t csize[2]; /* container size (min, max); if csize[0] != csize[1]
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* then value of 0 makes the field ignored
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*/
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size_t fsizec[2]; /* file size in container */
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size_t fsizer[2]; /* real file size */
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int encrypted; /* file is encrypted; 2 == ignore */
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unsigned int filepos[2]; /* file position in container */
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int res1; /* reserved / format specific */
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void *res2; /* reserved / format specific */
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struct cli_cdb *next;
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};
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#define CLI_MAX_TARGETS 10 /* maximum filetypes for a specific target */
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struct cli_mtarget {
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cli_file_t target[CLI_MAX_TARGETS];
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const char *name;
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uint8_t idx; /* idx of matcher */
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uint8_t ac_only;
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uint8_t enable_prefiltering;
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uint8_t target_count; /* must be synced with non-zero values in the target array */
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};
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#define CLI_MTARGETS 15
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static const struct cli_mtarget cli_mtargets[CLI_MTARGETS] = {
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/* All types for target, name, idx, ac_only, pre-filtering?, # of types */
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{{0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "GENERIC", 0, 0, 1, 1},
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{{CL_TYPE_MSEXE, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "PE", 1, 0, 1, 1},
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{{CL_TYPE_MSOLE2, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "OLE2", 2, 1, 0, 1},
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{{CL_TYPE_HTML, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "HTML", 3, 1, 0, 1},
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{{CL_TYPE_MAIL, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "MAIL", 4, 1, 1, 1},
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{{CL_TYPE_GRAPHICS, CL_TYPE_GIF, CL_TYPE_PNG, CL_TYPE_JPEG, CL_TYPE_TIFF, 0, 0, 0, 0, 0}, "GRAPHICS", 5, 1, 0, 5},
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{{CL_TYPE_ELF, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "ELF", 6, 1, 0, 1},
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{{CL_TYPE_TEXT_ASCII, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "ASCII", 7, 1, 1, 1},
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{{CL_TYPE_ERROR, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "NOT USED", 8, 1, 0, 1},
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{{CL_TYPE_MACHO, CL_TYPE_MACHO_UNIBIN, 0, 0, 0, 0, 0, 0, 0, 0}, "MACH-O", 9, 1, 0, 2},
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{{CL_TYPE_PDF, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "PDF", 10, 1, 0, 1},
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{{CL_TYPE_SWF, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "FLASH", 11, 1, 0, 1},
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{{CL_TYPE_JAVA, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "JAVA", 12, 1, 0, 1},
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{{CL_TYPE_INTERNAL, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "INTERNAL", 13, 1, 0, 1},
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{{CL_TYPE_OTHER, 0, 0, 0, 0, 0, 0, 0, 0, 0}, "OTHER", 14, 1, 0, 1}};
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// clang-format off
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#define CLI_OFF_ANY 0xffffffff
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#define CLI_OFF_NONE 0xfffffffe
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#define CLI_OFF_ABSOLUTE 1
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#define CLI_OFF_EOF_MINUS 2
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#define CLI_OFF_EP_PLUS 3
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#define CLI_OFF_EP_MINUS 4
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#define CLI_OFF_SL_PLUS 5
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#define CLI_OFF_SX_PLUS 6
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#define CLI_OFF_VERSION 7
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#define CLI_OFF_MACRO 8
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#define CLI_OFF_SE 9
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// clang-format on
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/**
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* @brief Non-magic scan matching using a file buffer for input. Older API
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*
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* This function is lower-level, requiring a call to `cli_exp_eval()` after the
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* match to evaluate logical signatures and yara rules.
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*
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* This function does not perform file type magic identification and does not use
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* the file format scanners.
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*
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* @param buffer The buffer to be matched.
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* @param length The length of the buffer or amount of bytets to match.
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* @param offset Offset into the buffer from which to start matching.
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* @param ctx The scanning context.
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* @param ftype If specified, may limit signature matching trie by target type corresponding with the specified CL_TYPE
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* @param acdata [in/out] A list of pattern maching data structs to contain match results, one for each pattern matching trie.
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* @return cl_error_t
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*/
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cl_error_t cli_scan_buff(const unsigned char *buffer, uint32_t length, uint32_t offset, cli_ctx *ctx, cli_file_t ftype, struct cli_ac_data **acdata);
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/**
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* @brief Non-magic scan matching using a file descriptor for input.
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*
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* This function does not perform file type magic identification and does not use
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* the file format scanners.
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*
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* This function uses the newer cli_scan_fmap() scanning API.
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*
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* @param desc File descriptor to be used for input
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* @param ctx The scanning context.
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* @param ftype If specified, may limit signature matching trie by target type corresponding with the specified CL_TYPE
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* @param ftonly Boolean indicating if the scan is for file-type detection only.
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* @param ftoffset [out] A list of file type signature matches with their corresponding offsets.
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* @param acmode Use AC_SCAN_VIR and AC_SCAN_FT to set scanning modes.
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* @param acres [out] A list of cli_ac_result AC pattern matching results.
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* @param name (optional) Original name of the file (to set fmap name metadata)
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* @return cl_error_t
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*/
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cl_error_t cli_scan_desc(int desc, cli_ctx *ctx, cli_file_t ftype, uint8_t ftonly, struct cli_matched_type **ftoffset, unsigned int acmode, struct cli_ac_result **acres, const char *name);
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/**
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* @brief Non-magic scan matching of the current fmap in the scan context. Newer API.
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*
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* This API will invoke cli_exp_eval() for you.
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*
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* @param ctx The scanning context.
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* @param ftype If specified, may limit signature matching trie by target type corresponding with the specified CL_TYPE
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* @param ftonly Boolean indicating if the scan is for file-type detection only.
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* @param ftoffset [out] A list of file type signature matches with their corresponding offsets.
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* @param acmode Use AC_SCAN_VIR and AC_SCAN_FT to set scanning modes.
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* @param acres [out] A list of cli_ac_result AC pattern matching results.
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* @param refhash MD5 hash of the current file, used to save time creating hashes and to limit scan recursion for the HandlerType logical signature FTM feature.
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* @return cl_error_t
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*/
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cl_error_t cli_scan_fmap(cli_ctx *ctx, cli_file_t ftype, uint8_t ftonly, struct cli_matched_type **ftoffset, unsigned int acmode, struct cli_ac_result **acres, unsigned char *refhash);
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/**
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* @brief Evaluate logical signatures and yara rules given the AC matching results
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* from cli_scan_buff() / matcher_run().
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*
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* @param ctx The scanning context.
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* @param root The AC trie root to match with.
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* @param acdata AC match results for a specific AC trie.
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* @param target_info File metadata used to evaluate logical sig and yara rule options.
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* @param hash Reference hash of the current file, used to limit recursion for the HandlerType logical signature FTM feature.
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* @return cl_error_t
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*/
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cl_error_t cli_exp_eval(cli_ctx *ctx, struct cli_matcher *root, struct cli_ac_data *acdata, struct cli_target_info *target_info, const char *hash);
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cl_error_t cli_caloff(const char *offstr, const struct cli_target_info *info, unsigned int target, uint32_t *offdata, uint32_t *offset_min, uint32_t *offset_max);
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/**
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* @brief Determine if an alert is a known false positive, using each fmap in the the ctx->container stack to check MD5, SHA1, and SHA256 hashes.
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*
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* @param ctx The scanning context.
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* @param vname (Optional) The name of the signature alert.
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* @return cl_error_t CL_CLEAN If an allow-list hash matches with one of the fmap hashes in the scan recursion stack.
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* CL_VIRUS If no allow-list hash matches.
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*/
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cl_error_t cli_check_fp(cli_ctx *ctx, const char *vname);
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cl_error_t cli_matchmeta(cli_ctx *ctx, const char *fname, size_t fsizec, size_t fsizer, int encrypted, unsigned int filepos, int res1, void *res2);
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/** Parse the executable headers and, if successful, populate exeinfo
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*
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* If target refers to a supported executable file type, the exe header
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* will be parsed and, if successful, info->status will be set to 1.
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* If parsing the exe header fails, info->status will be set to -1.
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* The caller MUST destroy info via a call to cli_targetinfo_destroy
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* regardless of what info->status is set to.
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*
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* @param info A structure to populate with info from the exe header. This
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* MUST be initialized via cli_targetinfo_init prior to calling
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* @param target the target executable file type. Possible values are:
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* - 1 - PE32 / PE32+
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* - 6 - ELF
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* - 9 - MachO
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* @param ctx The current scan context
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*/
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void cli_targetinfo(struct cli_target_info *info, unsigned int target, cli_ctx *ctx);
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#endif
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