Extend x86 instruction skipper to AMD64. Add plenty of arch dependent

opcodes to test it. Also fix DEBUG output & writes (zero'ing) to %xH regs
This commit is contained in:
gbeauche 2003-11-10 23:47:39 +00:00
parent b66d8ef433
commit 1169001df7

View File

@ -69,8 +69,9 @@ static bool sigsegv_do_install_handler(int sig);
enum transfer_size_t {
SIZE_UNKNOWN,
SIZE_BYTE,
SIZE_WORD,
SIZE_LONG
SIZE_WORD, // 2 bytes
SIZE_LONG, // 4 bytes
SIZE_QUAD, // 8 bytes
};
// Transfer type
@ -231,7 +232,7 @@ static void powerpc_decode_instruction(instruction_t *instruction, unsigned int
#if defined(__FreeBSD__)
#if (defined(i386) || defined(__i386__))
#define SIGSEGV_FAULT_INSTRUCTION (((struct sigcontext *)scp)->sc_eip)
#define SIGSEGV_REGISTER_FILE ((unsigned int *)&(((struct sigcontext *)scp)->sc_edi)) /* EDI is the first GPR (even below EIP) in sigcontext */
#define SIGSEGV_REGISTER_FILE ((unsigned long *)&(((struct sigcontext *)scp)->sc_edi)) /* EDI is the first GPR (even below EIP) in sigcontext */
#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
#endif
#endif
@ -240,7 +241,7 @@ static void powerpc_decode_instruction(instruction_t *instruction, unsigned int
#include <sys/ucontext.h>
#define SIGSEGV_CONTEXT_REGS (((ucontext_t *)scp)->uc_mcontext.gregs)
#define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_CONTEXT_REGS[14] /* should use REG_EIP instead */
#define SIGSEGV_REGISTER_FILE (unsigned int *)SIGSEGV_CONTEXT_REGS
#define SIGSEGV_REGISTER_FILE (unsigned long *)SIGSEGV_CONTEXT_REGS
#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
#endif
#if (defined(x86_64) || defined(__x86_64__))
@ -248,6 +249,7 @@ static void powerpc_decode_instruction(instruction_t *instruction, unsigned int
#define SIGSEGV_CONTEXT_REGS (((ucontext_t *)scp)->uc_mcontext.gregs)
#define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_CONTEXT_REGS[16] /* should use REG_RIP instead */
#define SIGSEGV_REGISTER_FILE (unsigned long *)SIGSEGV_CONTEXT_REGS
#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
#endif
#if (defined(ia64) || defined(__ia64__))
#define SIGSEGV_FAULT_INSTRUCTION (((struct sigcontext *)scp)->sc_ip & ~0x3ULL) /* slot number is in bits 0 and 1 */
@ -273,7 +275,7 @@ static void powerpc_decode_instruction(instruction_t *instruction, unsigned int
#define SIGSEGV_FAULT_HANDLER_ARGS &scs
#define SIGSEGV_FAULT_ADDRESS scp->cr2
#define SIGSEGV_FAULT_INSTRUCTION scp->eip
#define SIGSEGV_REGISTER_FILE (unsigned int *)scp
#define SIGSEGV_REGISTER_FILE (unsigned long *)scp
#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
#endif
#if (defined(sparc) || defined(__sparc__))
@ -384,7 +386,7 @@ static sigsegv_address_t get_fault_address(struct sigcontext *scp)
#define SIGSEGV_FAULT_HANDLER_ARGS sig, code, scp, addr
#define SIGSEGV_FAULT_ADDRESS addr
#define SIGSEGV_FAULT_INSTRUCTION scp->sc_eip
#define SIGSEGV_REGISTER_FILE ((unsigned int *)&scp->sc_edi)
#define SIGSEGV_REGISTER_FILE ((unsigned long *)&scp->sc_edi)
#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
#endif
#endif
@ -577,9 +579,10 @@ handleExceptions(void *priv)
#ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION
// Decode and skip X86 instruction
#if (defined(i386) || defined(__i386__))
#if (defined(i386) || defined(__i386__)) || defined(__x86_64__)
#if defined(__linux__)
enum {
#if (defined(i386) || defined(__i386__))
X86_REG_EIP = 14,
X86_REG_EAX = 11,
X86_REG_ECX = 10,
@ -589,10 +592,31 @@ enum {
X86_REG_EBP = 6,
X86_REG_ESI = 5,
X86_REG_EDI = 4
#endif
#if defined(__x86_64__)
X86_REG_R8 = 0,
X86_REG_R9 = 1,
X86_REG_R10 = 2,
X86_REG_R11 = 3,
X86_REG_R12 = 4,
X86_REG_R13 = 5,
X86_REG_R14 = 6,
X86_REG_R15 = 7,
X86_REG_EDI = 8,
X86_REG_ESI = 9,
X86_REG_EBP = 10,
X86_REG_EBX = 11,
X86_REG_EDX = 12,
X86_REG_EAX = 13,
X86_REG_ECX = 14,
X86_REG_ESP = 15,
X86_REG_EIP = 16
#endif
};
#endif
#if defined(__NetBSD__) || defined(__FreeBSD__)
enum {
#if (defined(i386) || defined(__i386__))
X86_REG_EIP = 10,
X86_REG_EAX = 7,
X86_REG_ECX = 6,
@ -602,6 +626,7 @@ enum {
X86_REG_EBP = 2,
X86_REG_ESI = 1,
X86_REG_EDI = 0
#endif
};
#endif
// FIXME: this is partly redundant with the instruction decoding phase
@ -638,7 +663,7 @@ static inline int ix86_step_over_modrm(unsigned char * p)
return offset;
}
static bool ix86_skip_instruction(unsigned int * regs)
static bool ix86_skip_instruction(unsigned long * regs)
{
unsigned char * eip = (unsigned char *)regs[X86_REG_EIP];
@ -651,6 +676,11 @@ static bool ix86_skip_instruction(unsigned int * regs)
int reg = -1;
int len = 0;
#if DEBUG
printf("IP: %p [%02x %02x %02x %02x...]\n",
eip, eip[0], eip[1], eip[2], eip[3]);
#endif
// Operand size prefix
if (*eip == 0x66) {
eip++;
@ -658,6 +688,39 @@ static bool ix86_skip_instruction(unsigned int * regs)
transfer_size = SIZE_WORD;
}
// REX prefix
#if defined(__x86_64__)
struct rex_t {
unsigned char W;
unsigned char R;
unsigned char X;
unsigned char B;
};
rex_t rex = { 0, 0, 0, 0 };
bool has_rex = false;
if ((*eip & 0xf0) == 0x40) {
has_rex = true;
const unsigned char b = *eip;
rex.W = b & (1 << 3);
rex.R = b & (1 << 2);
rex.X = b & (1 << 1);
rex.B = b & (1 << 0);
#if DEBUG
printf("REX: %c,%c,%c,%c\n",
rex.W ? 'W' : '_',
rex.R ? 'R' : '_',
rex.X ? 'X' : '_',
rex.B ? 'B' : '_');
#endif
eip++;
len++;
if (rex.W)
transfer_size = SIZE_QUAD;
}
#else
const bool has_rex = false;
#endif
// Decode instruction
switch (eip[0]) {
case 0x0f:
@ -727,24 +790,39 @@ static bool ix86_skip_instruction(unsigned int * regs)
return false;
}
#if defined(__x86_64__)
if (rex.R)
reg += 8;
#endif
if (transfer_type == SIGSEGV_TRANSFER_LOAD && reg != -1) {
static const int x86_reg_map[8] = {
static const int x86_reg_map[] = {
X86_REG_EAX, X86_REG_ECX, X86_REG_EDX, X86_REG_EBX,
X86_REG_ESP, X86_REG_EBP, X86_REG_ESI, X86_REG_EDI
X86_REG_ESP, X86_REG_EBP, X86_REG_ESI, X86_REG_EDI,
#if defined(__x86_64__)
X86_REG_R8, X86_REG_R9, X86_REG_R10, X86_REG_R11,
X86_REG_R12, X86_REG_R13, X86_REG_R14, X86_REG_R15,
#endif
};
if (reg < 0 || reg >= 8)
if (reg < 0 || reg >= (sizeof(x86_reg_map)/sizeof(x86_reg_map[0]) - 1))
return false;
// Set 0 to the relevant register part
// NOTE: this is only valid for MOV alike instructions
int rloc = x86_reg_map[reg];
switch (transfer_size) {
case SIZE_BYTE:
regs[rloc] = (regs[rloc] & ~0xff);
if (!has_rex && reg >= 4)
regs[rloc - 4] = (regs[rloc - 4] & ~0xff00L);
else
regs[rloc] = (regs[rloc] & ~0xffL);
break;
case SIZE_WORD:
regs[rloc] = (regs[rloc] & ~0xffff);
regs[rloc] = (regs[rloc] & ~0xffffL);
break;
case SIZE_LONG:
case SIZE_QUAD: // zero-extension
regs[rloc] = 0;
break;
}
@ -752,15 +830,51 @@ static bool ix86_skip_instruction(unsigned int * regs)
#if DEBUG
printf("%08x: %s %s access", regs[X86_REG_EIP],
transfer_size == SIZE_BYTE ? "byte" : transfer_size == SIZE_WORD ? "word" : "long",
transfer_size == SIZE_BYTE ? "byte" :
transfer_size == SIZE_WORD ? "word" :
transfer_size == SIZE_LONG ? "long" :
transfer_size == SIZE_QUAD ? "quad" : "unknown",
transfer_type == SIGSEGV_TRANSFER_LOAD ? "read" : "write");
if (reg != -1) {
static const char * x86_reg_str_map[8] = {
"eax", "ecx", "edx", "ebx",
"esp", "ebp", "esi", "edi"
static const char * x86_byte_reg_str_map[] = {
"al", "cl", "dl", "bl",
"spl", "bpl", "sil", "dil",
"r8b", "r9b", "r10b", "r11b",
"r12b", "r13b", "r14b", "r15b",
"ah", "ch", "dh", "bh",
};
printf(" %s register %%%s", transfer_type == SIGSEGV_TRANSFER_LOAD ? "to" : "from", x86_reg_str_map[reg]);
static const char * x86_word_reg_str_map[] = {
"ax", "cx", "dx", "bx",
"sp", "bp", "si", "di",
"r8w", "r9w", "r10w", "r11w",
"r12w", "r13w", "r14w", "r15w",
};
static const char *x86_long_reg_str_map[] = {
"eax", "ecx", "edx", "ebx",
"esp", "ebp", "esi", "edi",
"r8d", "r9d", "r10d", "r11d",
"r12d", "r13d", "r14d", "r15d",
};
static const char *x86_quad_reg_str_map[] = {
"rax", "rcx", "rdx", "rbx",
"rsp", "rbp", "rsi", "rdi",
"r8", "r9", "r10", "r11",
"r12", "r13", "r14", "r15",
};
const char * reg_str = NULL;
switch (transfer_size) {
case SIZE_BYTE:
reg_str = x86_byte_reg_str_map[(!has_rex && reg >= 4 ? 12 : 0) + reg];
break;
case SIZE_WORD: reg_str = x86_word_reg_str_map[reg]; break;
case SIZE_LONG: reg_str = x86_long_reg_str_map[reg]; break;
case SIZE_QUAD: reg_str = x86_quad_reg_str_map[reg]; break;
}
if (reg_str)
printf(" %s register %%%s",
transfer_type == SIGSEGV_TRANSFER_LOAD ? "to" : "from",
reg_str);
}
printf(", %d bytes instruction\n", len);
#endif
@ -1268,6 +1382,63 @@ static sigsegv_return_t sigsegv_insn_handler(sigsegv_address_t fault_address, si
return SIGSEGV_RETURN_FAILURE;
}
// More sophisticated tests for instruction skipper
static bool arch_insn_skipper_tests()
{
#if (defined(i386) || defined(__i386__)) || defined(__x86_64__)
static const unsigned char code[] = {
0x8a, 0x00, // mov (%eax),%al
0x8a, 0x2c, 0x18, // mov (%eax,%ebx,1),%ch
0x88, 0x20, // mov %ah,(%eax)
0x88, 0x08, // mov %cl,(%eax)
0x66, 0x8b, 0x00, // mov (%eax),%ax
0x66, 0x8b, 0x0c, 0x18, // mov (%eax,%ebx,1),%cx
0x66, 0x89, 0x00, // mov %ax,(%eax)
0x66, 0x89, 0x0c, 0x18, // mov %cx,(%eax,%ebx,1)
0x8b, 0x00, // mov (%eax),%eax
0x8b, 0x0c, 0x18, // mov (%eax,%ebx,1),%ecx
0x89, 0x00, // mov %eax,(%eax)
0x89, 0x0c, 0x18, // mov %ecx,(%eax,%ebx,1)
#if defined(__x86_64__)
0x44, 0x8a, 0x00, // mov (%rax),%r8b
0x44, 0x8a, 0x20, // mov (%rax),%r12b
0x42, 0x8a, 0x3c, 0x10, // mov (%rax,%r10,1),%dil
0x44, 0x88, 0x00, // mov %r8b,(%rax)
0x44, 0x88, 0x20, // mov %r12b,(%rax)
0x42, 0x88, 0x3c, 0x10, // mov %dil,(%rax,%r10,1)
0x66, 0x44, 0x8b, 0x00, // mov (%rax),%r8w
0x66, 0x42, 0x8b, 0x0c, 0x10, // mov (%rax,%r10,1),%cx
0x66, 0x44, 0x89, 0x00, // mov %r8w,(%rax)
0x66, 0x42, 0x89, 0x0c, 0x10, // mov %cx,(%rax,%r10,1)
0x44, 0x8b, 0x00, // mov (%rax),%r8d
0x42, 0x8b, 0x0c, 0x10, // mov (%rax,%r10,1),%ecx
0x44, 0x89, 0x00, // mov %r8d,(%rax)
0x42, 0x89, 0x0c, 0x10, // mov %ecx,(%rax,%r10,1)
0x48, 0x8b, 0x08, // mov (%rax),%rcx
0x4c, 0x8b, 0x18, // mov (%rax),%r11
0x4a, 0x8b, 0x0c, 0x10, // mov (%rax,%r10,1),%rcx
0x4e, 0x8b, 0x1c, 0x10, // mov (%rax,%r10,1),%r11
0x48, 0x89, 0x08, // mov %rcx,(%rax)
0x4c, 0x89, 0x18, // mov %r11,(%rax)
0x4a, 0x89, 0x0c, 0x10, // mov %rcx,(%rax,%r10,1)
0x4e, 0x89, 0x1c, 0x10, // mov %r11,(%rax,%r10,1)
#endif
0 // end
};
const int N_REGS = 20;
unsigned long regs[N_REGS];
for (int i = 0; i < N_REGS; i++)
regs[i] = i;
const unsigned long start_code = (unsigned long)&code;
regs[X86_REG_EIP] = start_code;
while ((regs[X86_REG_EIP] - start_code) < (sizeof(code) - 1)
&& ix86_skip_instruction(regs))
; /* simply iterate */
return (regs[X86_REG_EIP] - start_code) == (sizeof(code) - 1);
#endif
return true;
}
#endif
int main(void)
@ -1314,9 +1485,10 @@ int main(void)
return 8;
#define TEST_SKIP_INSTRUCTION(TYPE) do { \
const unsigned int TAG = 0x12345678; \
const unsigned long TAG = 0x12345678 | \
(sizeof(long) == 8 ? 0x9abcdef0UL << 31 : 0); \
TYPE data = *((TYPE *)(page + sizeof(TYPE))); \
volatile unsigned int effect = data + TAG; \
volatile unsigned long effect = data + TAG; \
if (effect != TAG) \
return 9; \
} while (0)
@ -1329,25 +1501,14 @@ int main(void)
TEST_SKIP_INSTRUCTION(unsigned char);
TEST_SKIP_INSTRUCTION(unsigned short);
TEST_SKIP_INSTRUCTION(unsigned int);
TEST_SKIP_INSTRUCTION(unsigned long);
L_e_region2:
#endif
if (!arch_insn_skipper_tests())
return 20;
vm_exit();
return 0;
}
#endif