/*emulation_length = ( (dec_instr->str_op_length < (0x1000 - PAGE_OFFSET_4KB(write_gva))) ?
dec_instr->str_op_length :
(0x1000 - PAGE_OFFSET_4KB(write_gva)));*/
- emulation_length = ( (dec_instr->str_op_length * (dec_instr->dst_operand.size) < (0x1000 - PAGE_OFFSET_4KB(write_gva))) ?
- dec_instr->str_op_length * dec_instr->dst_operand.size :
- (0x1000 - PAGE_OFFSET_4KB(write_gva)));
+
+ if ((dec_instr->str_op_length * (dec_instr->dst_operand.size)) < (0x1000 - PAGE_OFFSET_4KB(write_gva))) {
+ emulation_length = dec_instr->str_op_length * dec_instr->dst_operand.size;
+ } else {
+ emulation_length = (0x1000 - PAGE_OFFSET_4KB(write_gva));
+ PrintError("Warning: emulate_string_write_op emulating %u length operation, but request is for %u length\n",
+ emulation_length, (uint32_t)(dec_instr->str_op_length*(dec_instr->dst_operand.size)));
+ }
/* ** Fix emulation length so that it doesn't overrun over the src page either ** */
emulation_iter_cnt = emulation_length / dec_instr->dst_operand.size;
}
+
+/*
+ This function is intended to handle pure read hooks, pure write hook, and full hooks,
+ with and without backing memory for writes
+
+ read_fn == NULL
+ orig_src_addr == NULL => data at read_gpa is read
+ orig_src_addr != NULL => data at orig_src_addr is read
+ read_fn != NULL data is collected using read_fn
+
+ write_fn == NULL
+ orig_dst_addr == NULL => data is written to write_gpa
+ orig_dst_addr != NULL => data is written to orig_dst_addr
+ write_fn != NULL
+ orig_dst_addr == NULL => data is sent to write_fn
+ orig_dst_addr != NULL => data is written to orig_dst_addr, then via write_fn
+
+
+*/
+static int emulate_string_op(struct guest_info * info, struct x86_instr * dec_instr,
+ addr_t read_gva, addr_t read_gpa, addr_t orig_src_addr,
+ addr_t write_gva, addr_t write_gpa, addr_t orig_dst_addr,
+ int (*read_fn)(struct guest_info * core, addr_t guest_addr, void * src, uint_t length, void * priv_data),
+ int (*write_fn)(struct guest_info * core, addr_t guest_addr, void * dst, uint_t length, void * priv_data),
+ void * priv_data)
+{
+ uint_t src_emulation_length = 0;
+ uint_t dst_emulation_length = 0;
+ uint_t emulation_length = 0;
+ uint_t emulation_iter_cnt = 0;
+ addr_t tmp_rcx = 0;
+ addr_t src_addr, dst_addr;
+
+
+ // Sanity check the decoded instruction
+
+ if (info->shdw_pg_mode == SHADOW_PAGING) {
+ if (!read_fn && (dec_instr->src_operand.operand != read_gva)) {
+ PrintError("Inconsistency between Pagefault and Instruction Decode XED_ADDR=%p, PF_ADDR=%p (Read)\n",
+ (void *)dec_instr->src_operand.operand, (void *)read_gva);
+ return -1;
+ }
+ if (!write_fn && (dec_instr->dst_operand.operand != write_gva)) {
+ PrintError("Inconsistency between Pagefault and Instruction Decode XED_ADDR=%p, PF_ADDR=%p (Write)\n",
+ (void *)dec_instr->dst_operand.operand, (void *)write_gva);
+ return -1;
+ }
+ } else {
+ // Nested paging (Need check??)
+ }
+
+
+ if (dec_instr->src_operand.size != dec_instr->dst_operand.size) {
+ PrintError("Source and Destination Operands are of different sizes\n");
+ return -1;
+ }
+
+
+ // We will only read up to the next page boundary
+
+ if ((dec_instr->str_op_length * (dec_instr->src_operand.size)) < (0x1000 - PAGE_OFFSET_4KB(read_gva))) {
+ src_emulation_length = dec_instr->str_op_length * dec_instr->src_operand.size;
+ } else {
+ src_emulation_length = (0x1000 - PAGE_OFFSET_4KB(read_gva));
+ PrintError("Warning: emulate_string_op emulating src of %u length operation, but request is for %u length\n",
+ src_emulation_length, (uint32_t) (dec_instr->str_op_length*(dec_instr->src_operand.size)));
+ }
+
+ // We will only write up to the next page boundary
+
+ if ((dec_instr->str_op_length * (dec_instr->dst_operand.size)) < (0x1000 - PAGE_OFFSET_4KB(write_gva))) {
+ dst_emulation_length = dec_instr->str_op_length * dec_instr->dst_operand.size;
+ } else {
+ dst_emulation_length = (0x1000 - PAGE_OFFSET_4KB(write_gva));
+ PrintError("Warning: emulate_string_op emulating dst of %u length operation, but request is for %u length\n",
+ dst_emulation_length, (uint32_t) (dec_instr->str_op_length*(dec_instr->dst_operand.size)));
+ }
+
+ // We will only copy the minimum of what is available to be read or written
+
+ if (src_emulation_length<dst_emulation_length) {
+ emulation_length=src_emulation_length;
+ PrintError("Warning: emulate_string_op has src length %u but dst length %u\n", src_emulation_length, dst_emulation_length);
+ } else if (src_emulation_length>dst_emulation_length) {
+ emulation_length=dst_emulation_length;
+ PrintError("Warning: emulate_string_op has src length %u but dst length %u\n", src_emulation_length, dst_emulation_length);
+ } else {
+ // equal
+ emulation_length=src_emulation_length;
+ }
+
+
+ // Fetch the data
+
+ if (read_fn) {
+ src_addr = (addr_t) V3_Malloc(emulation_length); // hideous - should reuse memory
+ if (!src_addr) {
+ PrintError("Unable to allocate space for read operation in emulate_string_read_op\n");
+ return -1;
+ }
+ if (read_fn(info, read_gpa, (void *)src_addr, emulation_length, priv_data) != emulation_length) {
+ PrintError("Did not fully read hooked data in emulate_string_op\n");
+ return -1;
+ }
+ } else {
+ if (orig_src_addr) {
+ src_addr=orig_src_addr;
+ } else {
+ if (info->mem_mode == PHYSICAL_MEM) {
+ if (v3_gpa_to_hva(info, dec_instr->src_operand.operand, &src_addr) == -1) {
+ PrintError("Could not translate write Source (Physical) to host VA\n");
+ return -1;
+ }
+ } else {
+ if (v3_gva_to_hva(info, dec_instr->src_operand.operand, &src_addr) == -1) {
+ PrintError("Could not translate write Source (Virtual) to host VA\n");
+ return -1;
+ }
+ }
+ }
+ }
+
+ // Now src_addr points to the fetched data in HVA
+
+ // Allocate space for the write, in case we need to copy out later
+ if (write_fn) {
+ if (orig_dst_addr) {
+ dst_addr=orig_dst_addr;
+ } else {
+ dst_addr = (addr_t) V3_Malloc(emulation_length); // yuck
+ if (!dst_addr) {
+ PrintError("Unable to allocate space for write operation in emulate_string_op\n");
+ if (read_fn) {
+ V3_Free((void*)src_addr);
+ }
+ return -1;
+ }
+ }
+ } else {
+ if (orig_dst_addr) {
+ dst_addr=orig_dst_addr;
+ } else {
+ if (info->mem_mode == PHYSICAL_MEM) {
+ if (v3_gpa_to_hva(info, dec_instr->dst_operand.operand, &dst_addr) == -1) {
+ PrintError("Could not translate write Dest (Physical) to host VA\n");
+ return -1;
+ }
+ } else {
+ if (v3_gva_to_hva(info, dec_instr->dst_operand.operand, &dst_addr) == -1) {
+ PrintError("Could not translate write Dest (Virtual) to host VA\n");
+ return -1;
+ }
+ }
+ }
+ }
+
+ // Now dst_addr points to where we will copy the data
+
+ // How many items to copy
+ emulation_iter_cnt = emulation_length / dec_instr->dst_operand.size;
+ tmp_rcx = emulation_iter_cnt;
+
+
+ switch (dec_instr->op_type) {
+
+ case V3_OP_MOVS: {
+
+ if (dec_instr->dst_operand.size == 1) {
+ movs8((addr_t *)&dst_addr, &src_addr, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags));
+ } else if (dec_instr->dst_operand.size == 2) {
+ movs16((addr_t *)&dst_addr, &src_addr, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags));
+ } else if (dec_instr->dst_operand.size == 4) {
+ movs32((addr_t *)&dst_addr, &src_addr, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags));
+#ifdef __V3_64BIT__
+ } else if (dec_instr->dst_operand.size == 8) {
+ movs64((addr_t *)&dst_addr, &src_addr, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags));
+#endif
+ } else {
+ PrintError("Invalid operand length\n");
+ return -1;
+ }
+
+ // Can't these count down too? - PAD
+
+ info->vm_regs.rdi += emulation_length;
+ info->vm_regs.rsi += emulation_length;
+
+ // RCX is only modified if the rep prefix is present
+ if (dec_instr->prefixes.rep == 1) {
+ info->vm_regs.rcx -= emulation_iter_cnt;
+ }
+
+ }
+ break;
+
+ case V3_OP_STOS: {
+
+ if (dec_instr->dst_operand.size == 1) {
+ stos8((addr_t *)&dst_addr, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags));
+ } else if (dec_instr->dst_operand.size == 2) {
+ stos16((addr_t *)&dst_addr, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags));
+ } else if (dec_instr->dst_operand.size == 4) {
+ stos32((addr_t *)&dst_addr, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags));
+#ifdef __V3_64BIT__
+ } else if (dec_instr->dst_operand.size == 8) {
+ stos64((addr_t *)&dst_addr, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags));
+#endif
+ } else {
+ PrintError("Invalid operand length\n");
+ return -1;
+ }
+
+ info->vm_regs.rdi += emulation_length;
+
+ // RCX is only modified if the rep prefix is present
+ if (dec_instr->prefixes.rep == 1) {
+ info->vm_regs.rcx -= emulation_iter_cnt;
+ }
+
+ }
+ break;
+
+ default: {
+ PrintError("Unimplemented String operation\n");
+ return -1;
+ }
+ break;
+ }
+
+ // At this point, the data has been written over dst_addr, which
+ // is either our temporary buffer, or it's the requested target in orig_dst_addr
+
+ if (write_fn) {
+ if (write_fn(info, write_gpa, (void *)dst_addr, emulation_length, priv_data) != emulation_length) {
+ PrintError("Did not fully write hooked data\n");
+ return -1;
+ }
+ }
+
+ if (emulation_length == dec_instr->str_op_length) {
+ info->rip += dec_instr->instr_length;
+ }
+
+
+ // Delete temporary buffers
+ if (read_fn) {
+ V3_Free((void*)src_addr);
+ }
+ if (write_fn && !orig_dst_addr) {
+ V3_Free((void*)dst_addr);
+ }
+
+
+ return emulation_length;
+}
+
+
+
+
+
static int emulate_xchg_write_op(struct guest_info * info, struct x86_instr * dec_instr,
addr_t write_gva, addr_t write_gpa, addr_t dst_addr,
int (*write_fn)(struct guest_info * core, addr_t guest_addr, void * src, uint_t length, void * priv_data),
}
if (dec_instr.is_str_op) {
- PrintError("String operations not implemented on fully hooked regions\n");
- return -1;
+ return emulate_string_op(info,&dec_instr,
+ read_gva,read_gpa,0,
+ 0, 0, 0,
+ read_fn,write_fn,
+ priv_data);
} else if (dec_instr.op_type == V3_OP_XCHG) {
return emulate_xchg_read_op(info, &dec_instr, read_gva, read_gpa, src_addr, read_fn, write_fn, priv_data);
}
