875abb8724
- no longer inject fewer faults than instructed; - no longer apply a limit on the number of injected faults; - refactory to allow for random faults (type 99); - also allow for stop faults (type 50); - massive dead code cleanup; - move outdated test cruft into tests/ subdirectory; it is kept only as an example of how to use swifi. Change-Id: I8a3cb71902dfaadb7bf785723b917307db83d0d5
295 lines
7.5 KiB
C
295 lines
7.5 KiB
C
/*
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* Mach Operating System
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* Copyright (c) 1991,1990 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/*
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* Author: David B. Golub, Carnegie Mellon University
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* Date: 7/90
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*/
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#include "ddb.h"
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#include "db_sym.h"
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#include "swifi.h"
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#include "extra.h"
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/*
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* Multiple symbol tables
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*/
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#ifndef MAXNOSYMTABS
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#define MAXNOSYMTABS 3 /* mach, ux, emulator */
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#endif
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unsigned int db_maxoff = 0x10000;
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unsigned long modAddr = 0;
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/* NWT: fault injection routine only.
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* figure out start of function address given an address (off) in kernel text.
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* name = function name
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* value = function address
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* d = difference between off and function address
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* input is the desired address off and fault type
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* returns closest instruction address (if found), NULL otherwise
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*/
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unsigned long
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find_faulty_instr(db_expr_t off, int type, int *instr_len)
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{
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db_expr_t d;
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char *name;
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db_expr_t value, cur_value, prev_value = 0;
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int verbose=0, found=0;
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const char * mod_name = NULL;
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unsigned long mod_start;
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unsigned long mod_end;
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const char * sec_name = NULL;
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unsigned long sec_start;
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unsigned long sec_end;
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const char * sym_name = NULL;
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unsigned long sym_start;
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unsigned long sym_end;
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*instr_len = 0;
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if (kallsyms_address_to_symbol(off,
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&mod_name, &mod_start, &mod_end,
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&sec_name, &sec_start, &sec_end,
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&sym_name, &sym_start, &sym_end) == 0) {
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return(0);
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}
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value = (db_expr_t) sym_start;
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d = off - sym_start;
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name = (char *) sym_name;
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if (name == 0) {
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value = off;
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}
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if (value >= DB_SMALL_VALUE_MIN && value <= DB_SMALL_VALUE_MAX) {
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printk("0x%x", off);
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return 0;
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}
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if (name == 0 || d >= db_maxoff) {
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printk("0x%x", off);
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return 0 ;
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}
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/* 2) backup to start of function (SOF)
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* 3) delineate instruction boundaries, find instruction length too.
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*/
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if(verbose) {
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printk("function %s", sym_name);
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}
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/* 4) skip instructions until we get to our faulty address */
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cur_value = value;
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while(cur_value < sec_end) {
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if(verbose) {
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#if 0
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// db_printsym(cur_value, DB_STGY_PROC);
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// printk(":\t");
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#endif
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}
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prev_value=cur_value;
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modAddr=0;
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if(verbose) {
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#if 0
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//cur_value=db_disasm(prev_value, FALSE);
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#endif
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} else {
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cur_value=my_disasm(prev_value, FALSE);
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}
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/* 4a) bail out if instruction is leave (0xc9) */
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if(cur_value-prev_value == 1) {
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unsigned char *c;
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c=(unsigned char *) prev_value;
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if(text_read_ub(c)==0xc9) {
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if(verbose) printk("bailing out as we hit a leave\n");
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found=0;
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break;
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}
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}
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/* 5a) init fault: from SOF, look for movl $X, -Y(%ebp),
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* (C645Fxxx or C745Fxxx) and replace with nop.
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*/
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if(type==INIT_FAULT) {
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unsigned char *c;
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c=(unsigned char *) prev_value;
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if(*c==0x66 || *c==0x67)
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c++; /* override prefix */
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if(*c==0xC6 || *c==0xC7)
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c++; /* movb or movl imm */
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else
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continue;
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if(*c==0x45)
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c++; /* [ebp] */
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else
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continue;
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if(*c & 0x80)
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found=1; /* negative displacement */
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else
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continue;
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found=1;
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break;
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} else if(type==NOP_FAULT || type==STOP_FAULT) {
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/* 5b) nop*: replace instruction with nop */
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if(cur_value> off) {
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found=1;
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break;
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}
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} else if(type==DST_FAULT || type==SRC_FAULT) {
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/* 5c) dst/src: flip bits in mod/rm, sib, disp or imm fields */
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if(cur_value>off && (cur_value-prev_value) > 1) {
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found=1;
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break;
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}
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} else if(type==BRANCH_FAULT || type==LOOP_FAULT) {
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/* 5e) brc*: search forward utnil we hit a Jxx or rep (F3 or F2).
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* replace instr with nop.
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*/
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unsigned char *c;
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c=(unsigned char *) prev_value;
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/* look for repX prefix */
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if(text_read_ub(c)==0xf3 || text_read_ub(c)==0xf2) {
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if(verbose)
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printk("found repX prefix\n");
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/* take out repX prefix only */
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found=1;
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cur_value=prev_value+1;
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break;
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} else if( (text_read_ub(c)&0xf0)==0x70 ||
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(text_read_ub(c)>=0xe0 && text_read_ub(c)<=0xe2) ) {
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/* look for jXX 8 (7X), loop,jcx (e0-3), jXX 16/32 (0f 8X) */
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found=1;
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if(verbose)
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printk("found jXX rel8, loop or jcx\n");
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break;
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} else if(text_read_ub(c)==0x66 ||
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text_read_ub(c)==0x67) { /* override prefix */
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c++;
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} else if(text_read_ub(c++)==0xf && (text_read_ub(c)&0xf0)==0x80 ) {
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found=1; /* 0x0f 0x8X */
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if(verbose) printk("found branch!\n");
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break;
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}
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} else if(type==PTR_FAULT) {
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/* 5f) ptr: if instruction has regmodrm byte (i_has_modrm),
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* and mod field has address ([eyy]dispxx), eyy!=ebp
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* flip 1 bit in lower byte (0x0f) or any bit in following
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* bytes (sib, imm or disp).
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*/
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if(cur_value>off && modAddr) {
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unsigned char *c;
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c=(unsigned char *) modAddr;
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if( text_read_ub(c)>0x3f && text_read_ub(c)<0xc0 &&
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(text_read_ub(c)&7)!=5 ) {
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found=1;
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break;
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}
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}
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} else if(type==INTERFACE_FAULT) {
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/* 5f) i/f: look for movl XX(ebp), reg or movb XX(ebp), reg,
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* where XX is positive. replace instr with nop.
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* movl=0x8a, movb=0x8b, mod=01XXX101 (disp8[ebp]), disp>0
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*/
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unsigned char *c;
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c=(unsigned char *) prev_value;
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if( text_read_ub(c)==0x8a || text_read_ub(c)==0x8b) {
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c++;
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if( ((text_read_ub(c++))&0xc7)==0x45 && (text_read_ub(c)&0x80)==0 ) {
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/* 75% chance that we'll choose the next arg */
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if(random()&0x3) {
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found=1;
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break;
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} else {
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if(verbose) printk("skipped...\n");
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}
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}
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}
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}else if(type==IRQ_FAULT) {
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/* 5g) i/f: look for push reg or offset(reg) / popf,
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* where XX is positive. replace instr with nop.
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* movl=0x8a, movb=0x8b, mod=01XXX101 (disp8[ebp]), disp>0
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*/
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unsigned char *c;
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c=(unsigned char *) prev_value;
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if (((text_read_ub(c) & 0xf8) == 0x50) ||
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(text_read_ub(c) == 0xff)) {
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if (text_read_ub(c) == 0xff) {
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c++;
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#if 0
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//
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// Look for push x(ebp)
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#endif
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if ((text_read_ub(c) & 0x78) != 0x70) {
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continue;
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}
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/*
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// Skip the offset
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*/
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c++;
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}
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c++;
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if (text_read_ub(c) == 0x9d) {
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/*
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// Increment cur_value to include the
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// popf instruction
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*/
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cur_value++;
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found = 1;
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break;
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}
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}
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}
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}
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/* if we're doing nop fault, then we're done.
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*/
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if(found) {
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*instr_len=cur_value-prev_value;
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off=prev_value;
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if(verbose) {
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printk("%s", name);
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if (d) printk("+0x%x", d);
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printk(" @ %x, ", value);
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printk("instr @ %x, len=%d, ", off, *instr_len);
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}
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return off;
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} else {
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if(verbose) printk("cannot locate instruction in function\n");
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*instr_len=0;
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return 0;
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}
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}
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