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566 lines
15 KiB
566 lines
15 KiB
/*
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* Copyright (C) 2009 Sourcefire, Inc.
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*
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* Authors: Tomasz Kojm <tkojm@clamav.net>
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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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#include <stdio.h>
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#include <string.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <openssl/ssl.h>
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#include <openssl/err.h>
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#include "libclamav/crypto.h"
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#include "clamav.h"
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#include "cltypes.h"
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#include "others.h"
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#include "macho.h"
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#include "execs.h"
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#include "scanners.h"
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#define EC32(v, conv) (conv ? cbswap32(v) : v)
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#define EC64(v, conv) (conv ? cbswap64(v) : v)
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struct macho_hdr
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{
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uint32_t magic;
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uint32_t cpu_type;
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uint32_t cpu_subtype;
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uint32_t filetype;
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uint32_t ncmds;
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uint32_t sizeofcmds;
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uint32_t flags;
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};
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struct macho_load_cmd
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{
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uint32_t cmd;
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uint32_t cmdsize;
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};
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struct macho_segment_cmd
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{
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char segname[16];
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uint32_t vmaddr;
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uint32_t vmsize;
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uint32_t fileoff;
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uint32_t filesize;
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uint32_t maxprot;
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uint32_t initprot;
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uint32_t nsects;
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uint32_t flags;
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};
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struct macho_segment_cmd64
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{
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char segname[16];
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uint64_t vmaddr;
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uint64_t vmsize;
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uint64_t fileoff;
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uint64_t filesize;
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uint32_t maxprot;
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uint32_t initprot;
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uint32_t nsects;
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uint32_t flags;
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};
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struct macho_section
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{
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char sectname[16];
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char segname[16];
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uint32_t addr;
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uint32_t size;
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uint32_t offset;
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uint32_t align;
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uint32_t reloff;
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uint32_t nreloc;
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uint32_t flags;
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uint32_t res1;
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uint32_t res2;
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};
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struct macho_section64
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{
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char sectname[16];
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char segname[16];
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uint64_t addr;
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uint64_t size;
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uint32_t offset;
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uint32_t align;
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uint32_t reloff;
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uint32_t nreloc;
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uint32_t flags;
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uint32_t res1;
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uint32_t res2;
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};
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struct macho_thread_state_ppc
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{
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uint32_t srr0; /* PC */
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uint32_t srr1;
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uint32_t reg[32];
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uint32_t cr;
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uint32_t xer;
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uint32_t lr;
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uint32_t ctr;
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uint32_t mq;
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uint32_t vrsave;
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};
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struct macho_thread_state_ppc64
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{
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uint64_t srr0; /* PC */
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uint64_t srr1;
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uint64_t reg[32];
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uint32_t cr;
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uint64_t xer;
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uint64_t lr;
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uint64_t ctr;
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uint32_t vrsave;
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};
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struct macho_thread_state_x86
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{
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uint32_t eax;
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uint32_t ebx;
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uint32_t ecx;
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uint32_t edx;
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uint32_t edi;
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uint32_t esi;
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uint32_t ebp;
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uint32_t esp;
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uint32_t ss;
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uint32_t eflags;
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uint32_t eip;
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uint32_t cs;
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uint32_t ds;
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uint32_t es;
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uint32_t fs;
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uint32_t gs;
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};
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struct macho_fat_header
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{
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uint32_t magic;
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uint32_t nfats;
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};
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struct macho_fat_arch
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{
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uint32_t cputype;
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uint32_t cpusubtype;
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uint32_t offset;
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uint32_t size;
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uint32_t align;
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};
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#define RETURN_BROKEN \
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if(matcher) \
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return -1; \
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if(DETECT_BROKEN) { \
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cli_append_virus(ctx, "Heuristics.Broken.Executable"); \
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return CL_VIRUS; \
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} \
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return CL_EFORMAT
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static uint32_t cli_rawaddr(uint32_t vaddr, struct cli_exe_section *sects, uint16_t nsects, unsigned int *err)
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{
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unsigned int i, found = 0;
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for(i = 0; i < nsects; i++) {
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if(sects[i].rva <= vaddr && sects[i].rva + sects[i].vsz > vaddr) {
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found = 1;
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break;
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}
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}
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if(!found) {
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*err = 1;
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return 0;
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}
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*err = 0;
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return vaddr - sects[i].rva + sects[i].raw;
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}
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int cli_scanmacho(cli_ctx *ctx, struct cli_exe_info *fileinfo)
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{
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struct macho_hdr hdr;
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struct macho_load_cmd load_cmd;
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struct macho_segment_cmd segment_cmd;
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struct macho_segment_cmd64 segment_cmd64;
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struct macho_section section;
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struct macho_section64 section64;
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unsigned int i, j, sect = 0, conv, m64, nsects, matcher = 0;
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unsigned int arch = 0, ep = 0, err;
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struct cli_exe_section *sections = NULL;
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char name[16];
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fmap_t *map = *ctx->fmap;
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ssize_t at;
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if(fileinfo)
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matcher = 1;
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if(fmap_readn(map, &hdr, 0, sizeof(hdr)) != sizeof(hdr)) {
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cli_dbgmsg("cli_scanmacho: Can't read header\n");
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return matcher ? -1 : CL_EFORMAT;
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}
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at = sizeof(hdr);
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if(hdr.magic == 0xfeedface) {
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conv = 0;
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m64 = 0;
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} else if(hdr.magic == 0xcefaedfe) {
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conv = 1;
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m64 = 0;
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} else if(hdr.magic == 0xfeedfacf) {
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conv = 0;
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m64 = 1;
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} else if(hdr.magic == 0xcffaedfe) {
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conv = 1;
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m64 = 1;
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} else {
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cli_dbgmsg("cli_scanmacho: Incorrect magic\n");
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return matcher ? -1 : CL_EFORMAT;
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}
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switch(EC32(hdr.cpu_type, conv)) {
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case 7:
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if(!matcher)
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cli_dbgmsg("MACHO: CPU Type: Intel 32-bit\n");
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arch = 1;
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break;
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case 7 | 0x1000000:
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if(!matcher)
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cli_dbgmsg("MACHO: CPU Type: Intel 64-bit\n");
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break;
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case 12:
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if(!matcher)
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cli_dbgmsg("MACHO: CPU Type: ARM\n");
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break;
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case 14:
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if(!matcher)
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cli_dbgmsg("MACHO: CPU Type: SPARC\n");
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break;
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case 18:
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if(!matcher)
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cli_dbgmsg("MACHO: CPU Type: POWERPC 32-bit\n");
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arch = 2;
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break;
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case 18 | 0x1000000:
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if(!matcher)
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cli_dbgmsg("MACHO: CPU Type: POWERPC 64-bit\n");
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arch = 3;
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break;
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default:
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if(!matcher)
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cli_dbgmsg("MACHO: CPU Type: ** UNKNOWN ** (%u)\n", EC32(hdr.cpu_type, conv));
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break;
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}
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if(!matcher) switch(EC32(hdr.filetype, conv)) {
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case 0x1: /* MH_OBJECT */
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cli_dbgmsg("MACHO: Filetype: Relocatable object file\n");
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break;
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case 0x2: /* MH_EXECUTE */
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cli_dbgmsg("MACHO: Filetype: Executable\n");
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break;
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case 0x3: /* MH_FVMLIB */
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cli_dbgmsg("MACHO: Filetype: Fixed VM shared library file\n");
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break;
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case 0x4: /* MH_CORE */
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cli_dbgmsg("MACHO: Filetype: Core file\n");
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break;
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case 0x5: /* MH_PRELOAD */
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cli_dbgmsg("MACHO: Filetype: Preloaded executable file\n");
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break;
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case 0x6: /* MH_DYLIB */
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cli_dbgmsg("MACHO: Filetype: Dynamically bound shared library\n");
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break;
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case 0x7: /* MH_DYLINKER */
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cli_dbgmsg("MACHO: Filetype: Dynamic link editor\n");
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break;
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case 0x8: /* MH_BUNDLE */
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cli_dbgmsg("MACHO: Filetype: Dynamically bound bundle file\n");
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break;
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case 0x9: /* MH_DYLIB_STUB */
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cli_dbgmsg("MACHO: Filetype: Shared library stub for static\n");
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break;
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default:
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cli_dbgmsg("MACHO: Filetype: ** UNKNOWN ** (0x%x)\n", EC32(hdr.filetype, conv));
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}
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if(!matcher) {
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cli_dbgmsg("MACHO: Number of load commands: %u\n", EC32(hdr.ncmds, conv));
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cli_dbgmsg("MACHO: Size of load commands: %u\n", EC32(hdr.sizeofcmds, conv));
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}
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if(m64)
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at += 4;
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hdr.ncmds = EC32(hdr.ncmds, conv);
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if(!hdr.ncmds || hdr.ncmds > 1024) {
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cli_dbgmsg("cli_scanmacho: Invalid number of load commands (%u)\n", hdr.ncmds);
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RETURN_BROKEN;
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}
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for(i = 0; i < hdr.ncmds; i++) {
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if(fmap_readn(map, &load_cmd, at, sizeof(load_cmd)) != sizeof(load_cmd)) {
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cli_dbgmsg("cli_scanmacho: Can't read load command\n");
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free(sections);
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RETURN_BROKEN;
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}
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at += sizeof(load_cmd);
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/*
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if((m64 && EC32(load_cmd.cmdsize, conv) % 8) || (!m64 && EC32(load_cmd.cmdsize, conv) % 4)) {
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cli_dbgmsg("cli_scanmacho: Invalid command size (%u)\n", EC32(load_cmd.cmdsize, conv));
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free(sections);
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RETURN_BROKEN;
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}
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*/
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load_cmd.cmd = EC32(load_cmd.cmd, conv);
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if((m64 && load_cmd.cmd == 0x19) || (!m64 && load_cmd.cmd == 0x01)) { /* LC_SEGMENT */
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if(m64) {
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if(fmap_readn(map, &segment_cmd64, at, sizeof(segment_cmd64)) != sizeof(segment_cmd64)) {
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cli_dbgmsg("cli_scanmacho: Can't read segment command\n");
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free(sections);
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RETURN_BROKEN;
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}
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at += sizeof(segment_cmd64);
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nsects = EC32(segment_cmd64.nsects, conv);
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strncpy(name, segment_cmd64.segname, sizeof(name));
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name[sizeof(name)-1] = '\0';
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} else {
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if(fmap_readn(map, &segment_cmd, at, sizeof(segment_cmd)) != sizeof(segment_cmd)) {
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cli_dbgmsg("cli_scanmacho: Can't read segment command\n");
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free(sections);
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RETURN_BROKEN;
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}
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at += sizeof(segment_cmd);
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nsects = EC32(segment_cmd.nsects, conv);
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strncpy(name, segment_cmd.segname, sizeof(name));
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}
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if(!matcher) {
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name[sizeof(name)-1] = '\0';
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cli_dbgmsg("MACHO: Segment name: %s\n", name);
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cli_dbgmsg("MACHO: Number of sections: %u\n", nsects);
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}
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if(nsects > 255) {
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cli_dbgmsg("cli_scanmacho: Invalid number of sections\n");
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free(sections);
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RETURN_BROKEN;
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}
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if(!nsects) {
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if(!matcher)
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cli_dbgmsg("MACHO: ------------------\n");
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continue;
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}
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sections = (struct cli_exe_section *) cli_realloc2(sections, (sect + nsects) * sizeof(struct cli_exe_section));
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if(!sections) {
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cli_errmsg("cli_scanmacho: Can't allocate memory for 'sections'\n");
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return matcher ? -1 : CL_EMEM;
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}
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for(j = 0; j < nsects; j++) {
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if(m64) {
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if(fmap_readn(map, §ion64, at, sizeof(section64)) != sizeof(section64)) {
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cli_dbgmsg("cli_scanmacho: Can't read section\n");
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free(sections);
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RETURN_BROKEN;
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}
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at += sizeof(section64);
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sections[sect].rva = EC64(section64.addr, conv);
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sections[sect].vsz = EC64(section64.size, conv);
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sections[sect].raw = EC32(section64.offset, conv);
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section64.align = 1 << EC32(section64.align, conv);
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sections[sect].rsz = sections[sect].vsz + (section64.align - (sections[sect].vsz % section64.align)) % section64.align; /* most likely we can assume it's the same as .vsz */
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strncpy(name, section64.sectname, sizeof(name));
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} else {
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if(fmap_readn(map, §ion, at, sizeof(section)) != sizeof(section)) {
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cli_dbgmsg("cli_scanmacho: Can't read section\n");
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free(sections);
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RETURN_BROKEN;
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}
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at += sizeof(section);
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sections[sect].rva = EC32(section.addr, conv);
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sections[sect].vsz = EC32(section.size, conv);
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sections[sect].raw = EC32(section.offset, conv);
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section.align = 1 << EC32(section.align, conv);
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sections[sect].rsz = sections[sect].vsz + (section.align - (sections[sect].vsz % section.align)) % section.align;
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strncpy(name, section.sectname, sizeof(name));
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}
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if(!matcher) {
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name[sizeof(name)-1] = '\0';
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cli_dbgmsg("MACHO: --- Section %u ---\n", sect);
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cli_dbgmsg("MACHO: Name: %s\n", name);
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cli_dbgmsg("MACHO: Virtual address: 0x%x\n", (unsigned int) sections[sect].rva);
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cli_dbgmsg("MACHO: Virtual size: %u\n", (unsigned int) sections[sect].vsz);
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cli_dbgmsg("MACHO: Raw size: %u\n", (unsigned int) sections[sect].rsz);
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if(sections[sect].raw)
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cli_dbgmsg("MACHO: File offset: %u\n", (unsigned int) sections[sect].raw);
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}
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sect++;
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}
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if(!matcher)
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cli_dbgmsg("MACHO: ------------------\n");
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} else if(arch && (load_cmd.cmd == 0x4 || load_cmd.cmd == 0x5)) { /* LC_(UNIX)THREAD */
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at += 8;
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switch(arch) {
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case 1: /* x86 */
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{
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struct macho_thread_state_x86 thread_state_x86;
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if(fmap_readn(map, &thread_state_x86, at, sizeof(thread_state_x86)) != sizeof(thread_state_x86)) {
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cli_dbgmsg("cli_scanmacho: Can't read thread_state_x86\n");
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free(sections);
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RETURN_BROKEN;
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}
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at += sizeof(thread_state_x86);
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break;
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}
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case 2: /* PPC */
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{
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struct macho_thread_state_ppc thread_state_ppc;
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if(fmap_readn(map, &thread_state_ppc, at, sizeof(thread_state_ppc)) != sizeof(thread_state_ppc)) {
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cli_dbgmsg("cli_scanmacho: Can't read thread_state_ppc\n");
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|
free(sections);
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RETURN_BROKEN;
|
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}
|
|
at += sizeof(thread_state_ppc);
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ep = EC32(thread_state_ppc.srr0, conv);
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break;
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}
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case 3: /* PPC64 */
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{
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struct macho_thread_state_ppc64 thread_state_ppc64;
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if(fmap_readn(map, &thread_state_ppc64, at, sizeof(thread_state_ppc64)) != sizeof(thread_state_ppc64)) {
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cli_dbgmsg("cli_scanmacho: Can't read thread_state_ppc64\n");
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free(sections);
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RETURN_BROKEN;
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}
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at += sizeof(thread_state_ppc64);
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ep = EC64(thread_state_ppc64.srr0, conv);
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break;
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}
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default:
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cli_errmsg("cli_scanmacho: Invalid arch setting!\n");
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free(sections);
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return matcher ? -1 : CL_EARG;
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}
|
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} else {
|
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if(EC32(load_cmd.cmdsize, conv) > sizeof(load_cmd))
|
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at += EC32(load_cmd.cmdsize, conv) - sizeof(load_cmd);
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}
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}
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|
|
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if(ep) {
|
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if(!matcher)
|
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cli_dbgmsg("Entry Point: 0x%x\n", ep);
|
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if(sections) {
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ep = cli_rawaddr(ep, sections, sect, &err);
|
|
if(err) {
|
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cli_dbgmsg("cli_scanmacho: Can't calculate EP offset\n");
|
|
free(sections);
|
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return matcher ? -1 : CL_EFORMAT;
|
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}
|
|
if(!matcher)
|
|
cli_dbgmsg("Entry Point file offset: %u\n", ep);
|
|
}
|
|
}
|
|
|
|
if(matcher) {
|
|
fileinfo->ep = ep;
|
|
fileinfo->nsections = sect;
|
|
fileinfo->section = sections;
|
|
return 0;
|
|
} else {
|
|
free(sections);
|
|
return CL_SUCCESS;
|
|
}
|
|
}
|
|
|
|
int cli_machoheader(fmap_t *map, struct cli_exe_info *fileinfo)
|
|
{
|
|
cli_ctx ctx;
|
|
ctx.fmap = ↦
|
|
return cli_scanmacho(&ctx, fileinfo);
|
|
}
|
|
|
|
int cli_scanmacho_unibin(cli_ctx *ctx)
|
|
{
|
|
struct macho_fat_header fat_header;
|
|
struct macho_fat_arch fat_arch;
|
|
unsigned int conv, i, matcher = 0;
|
|
int ret = CL_CLEAN;
|
|
fmap_t *map = *ctx->fmap;
|
|
ssize_t at;
|
|
|
|
if(fmap_readn(map, &fat_header, 0, sizeof(fat_header)) != sizeof(fat_header)) {
|
|
cli_dbgmsg("cli_scanmacho_unibin: Can't read fat_header\n");
|
|
return CL_EFORMAT;
|
|
}
|
|
at = sizeof(fat_header);
|
|
|
|
if(fat_header.magic == 0xcafebabe) {
|
|
conv = 0;
|
|
} else if(fat_header.magic == 0xbebafeca) {
|
|
conv = 1;
|
|
} else {
|
|
cli_dbgmsg("cli_scanmacho_unibin: Incorrect magic\n");
|
|
return CL_EFORMAT;
|
|
}
|
|
|
|
fat_header.nfats = EC32(fat_header.nfats, conv);
|
|
if((fat_header.nfats & 0xffff) >= 39) /* Java Bytecode */
|
|
return CL_CLEAN;
|
|
|
|
if(fat_header.nfats > 32) {
|
|
cli_dbgmsg("cli_scanmacho_unibin: Invalid number of architectures\n");
|
|
return CL_EFORMAT;
|
|
}
|
|
cli_dbgmsg("UNIBIN: Number of architectures: %u\n", (unsigned int) fat_header.nfats);
|
|
for(i = 0; i < fat_header.nfats; i++) {
|
|
if(fmap_readn(map, &fat_arch, at, sizeof(fat_arch)) != sizeof(fat_arch)) {
|
|
cli_dbgmsg("cli_scanmacho_unibin: Can't read fat_arch\n");
|
|
RETURN_BROKEN;
|
|
}
|
|
at += sizeof(fat_arch);
|
|
fat_arch.offset = EC32(fat_arch.offset, conv);
|
|
fat_arch.size = EC32(fat_arch.size, conv);
|
|
cli_dbgmsg("UNIBIN: Binary %u of %u\n", i + 1, fat_header.nfats);
|
|
cli_dbgmsg("UNIBIN: File offset: %u\n", fat_arch.offset);
|
|
cli_dbgmsg("UNIBIN: File size: %u\n", fat_arch.size);
|
|
ret = cli_map_scan(map, fat_arch.offset, fat_arch.size, ctx, CL_TYPE_ANY);
|
|
if(ret == CL_VIRUS)
|
|
break;
|
|
}
|
|
|
|
return ret; /* result from the last binary */
|
|
}
|
|
|