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398 lines
11 KiB
398 lines
11 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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/* TODO:
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* - handle LC_THREAD
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* - integrate with the matcher
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*/
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#include <stdio.h>
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#include <string.h>
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#include <unistd.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 "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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#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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int cli_scanmacho(int fd, cli_ctx *ctx)
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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, vaddr, vsize, offset;
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char name[16];
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if(read(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
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cli_dbgmsg("cli_scanmacho: Can't read header\n");
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return CL_EFORMAT;
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}
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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 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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cli_dbgmsg("MACHO: CPU Type: Intel 32-bit\n");
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break;
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case 7 | 0x1000000:
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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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cli_dbgmsg("MACHO: CPU Type: ARM\n");
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break;
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case 14:
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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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cli_dbgmsg("MACHO: CPU Type: POWERPC 32-bit\n");
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break;
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case 18 | 0x1000000:
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cli_dbgmsg("MACHO: CPU Type: POWERPC 64-bit\n");
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break;
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default:
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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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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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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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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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if(DETECT_BROKEN) {
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if(ctx->virname)
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*ctx->virname = "Broken.Executable";
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return cli_checkfp(fd, ctx) ? CL_CLEAN : CL_VIRUS;
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}
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return CL_EFORMAT;
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}
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if(m64)
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lseek(fd, 4, SEEK_CUR);
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for(i = 0; i < EC32(hdr.ncmds, conv); i++) {
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if(read(fd, &load_cmd, sizeof(load_cmd)) != sizeof(load_cmd)) {
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cli_dbgmsg("cli_scanmacho: Can't read load command\n");
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if(DETECT_BROKEN) {
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if(ctx->virname)
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*ctx->virname = "Broken.Executable";
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return cli_checkfp(fd, ctx) ? CL_CLEAN : CL_VIRUS;
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}
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return CL_EFORMAT;
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}
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if((m64 && EC32(load_cmd.cmd, conv) == 0x19) || (!m64 && EC32(load_cmd.cmd, conv) == 0x01)) { /* LC_SEGMENT */
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if(m64) {
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if(read(fd, &segment_cmd64, sizeof(segment_cmd64)) != sizeof(segment_cmd64)) {
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cli_dbgmsg("cli_scanmacho: Can't read segment command\n");
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if(DETECT_BROKEN) {
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if(ctx->virname)
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*ctx->virname = "Broken.Executable";
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return cli_checkfp(fd, ctx) ? CL_CLEAN : CL_VIRUS;
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}
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return CL_EFORMAT;
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}
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nsects = EC32(segment_cmd64.nsects, conv);
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strncpy(name, segment_cmd64.segname, 16);
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} else {
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if(read(fd, &segment_cmd, sizeof(segment_cmd)) != sizeof(segment_cmd)) {
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cli_dbgmsg("cli_scanmacho: Can't read segment command\n");
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if(DETECT_BROKEN) {
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if(ctx->virname)
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*ctx->virname = "Broken.Executable";
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return cli_checkfp(fd, ctx) ? CL_CLEAN : CL_VIRUS;
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}
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return CL_EFORMAT;
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}
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nsects = EC32(segment_cmd.nsects, conv);
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strncpy(name, segment_cmd.segname, 16);
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}
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name[15] = 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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for(j = 0; j < nsects; j++) {
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if(m64) {
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if(read(fd, §ion64, sizeof(section64)) != sizeof(section64)) {
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cli_dbgmsg("cli_scanmacho: Can't read section\n");
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if(DETECT_BROKEN) {
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if(ctx->virname)
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*ctx->virname = "Broken.Executable";
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return cli_checkfp(fd, ctx) ? CL_CLEAN : CL_VIRUS;
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}
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return CL_EFORMAT;
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}
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vaddr = EC64(section64.addr, conv);
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vsize = EC64(section64.size, conv);
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offset = EC32(section64.offset, conv);
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strncpy(name, section64.sectname, 16);
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} else {
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if(read(fd, §ion, sizeof(section)) != sizeof(section)) {
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cli_dbgmsg("cli_scanmacho: Can't read section\n");
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if(DETECT_BROKEN) {
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if(ctx->virname)
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*ctx->virname = "Broken.Executable";
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return cli_checkfp(fd, ctx) ? CL_CLEAN : CL_VIRUS;
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}
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return CL_EFORMAT;
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}
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vaddr = EC32(section.addr, conv);
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vsize = EC32(section.size, conv);
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offset = EC32(section.offset, conv);
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strncpy(name, section.sectname, 16);
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}
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name[15] = 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", vaddr);
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cli_dbgmsg("MACHO: Virtual size: %u\n", vsize);
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if(offset)
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cli_dbgmsg("MACHO: File offset: %u\n", offset);
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sect++;
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}
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cli_dbgmsg("MACHO: ------------------\n");
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} else {
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if(EC32(load_cmd.cmdsize, conv) > sizeof(load_cmd))
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lseek(fd, EC32(load_cmd.cmdsize, conv) - sizeof(load_cmd), SEEK_CUR);
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}
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}
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return CL_SUCCESS;
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}
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int cli_machoheader(int fd, struct cli_exe_info *elfinfo)
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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, vaddr, vsize, offset;
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cli_dbgmsg("in cli_machoheader()\n");
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if(read(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
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cli_dbgmsg("cli_scanmacho: Can't read header\n");
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return -1;
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}
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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 CL_EFORMAT;
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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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return -1;
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}
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if(m64)
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lseek(fd, 4, SEEK_CUR);
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for(i = 0; i < EC32(hdr.ncmds, conv); i++) {
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if(read(fd, &load_cmd, sizeof(load_cmd)) != sizeof(load_cmd)) {
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cli_dbgmsg("cli_scanmacho: Can't read load command\n");
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return -1;
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}
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if((m64 && EC32(load_cmd.cmd, conv) == 0x19) || (!m64 && EC32(load_cmd.cmd, conv) == 0x01)) { /* LC_SEGMENT */
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if(m64) {
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if(read(fd, &segment_cmd64, sizeof(segment_cmd64)) != sizeof(segment_cmd64)) {
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cli_dbgmsg("cli_scanmacho: Can't read segment command\n");
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return -1;
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}
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nsects = EC32(segment_cmd64.nsects, conv);
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} else {
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if(read(fd, &segment_cmd, sizeof(segment_cmd)) != sizeof(segment_cmd)) {
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cli_dbgmsg("cli_scanmacho: Can't read segment command\n");
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return -1;
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}
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nsects = EC32(segment_cmd.nsects, conv);
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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(read(fd, §ion64, sizeof(section64)) != sizeof(section64)) {
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cli_dbgmsg("cli_scanmacho: Can't read section\n");
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return -1;
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}
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vaddr = EC64(section64.addr, conv);
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vsize = EC64(section64.size, conv);
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offset = EC32(section64.offset, conv);
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} else {
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if(read(fd, §ion, sizeof(section)) != sizeof(section)) {
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cli_dbgmsg("cli_scanmacho: Can't read section\n");
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return -1;
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}
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vaddr = EC32(section.addr, conv);
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vsize = EC32(section.size, conv);
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offset = EC32(section.offset, conv);
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}
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sect++;
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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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lseek(fd, EC32(load_cmd.cmdsize, conv) - sizeof(load_cmd), SEEK_CUR);
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}
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}
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return 0;
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}
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