/*
* Copyright (c) 2018 Virtuozzo International GmbH
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
*
*/
#include "qemu/osdep.h"
#include "err.h"
#include "addrspace.h"
#include "pe.h"
#include "pdb.h"
#include "kdbg.h"
#include "download.h"
#include "qemu/win_dump_defs.h"
#define SYM_URL_BASE "https://msdl.microsoft.com/download/symbols/"
#define PDB_NAME "ntkrnlmp.pdb"
#define INITIAL_MXCSR 0x1f80
typedef struct idt_desc {
uint16_t offset1; /* offset bits 0..15 */
uint16_t selector;
uint8_t ist;
uint8_t type_attr;
uint16_t offset2; /* offset bits 16..31 */
uint32_t offset3; /* offset bits 32..63 */
uint32_t rsrvd;
} __attribute__ ((packed)) idt_desc_t;
static uint64_t idt_desc_addr(idt_desc_t desc)
{
return (uint64_t)desc.offset1 | ((uint64_t)desc.offset2 << 16) |
((uint64_t)desc.offset3 << 32);
}
static const uint64_t SharedUserData = 0xfffff78000000000;
#define KUSD_OFFSET_SUITE_MASK 0x2d0
#define KUSD_OFFSET_PRODUCT_TYPE 0x264
#define SYM_RESOLVE(base, r, s) ((s = pdb_resolve(base, r, #s)),\
s ? printf(#s" = 0x%016"PRIx64"\n", s) :\
eprintf("Failed to resolve "#s"\n"), s)
static uint64_t rol(uint64_t x, uint64_t y)
{
return (x << y) | (x >> (64 - y));
}
/*
* Decoding algorithm can be found in Volatility project
*/
static void kdbg_decode(uint64_t *dst, uint64_t *src, size_t size,
uint64_t kwn, uint64_t kwa, uint64_t kdbe)
{
size_t i;
assert(size % sizeof(uint64_t) == 0);
for (i = 0; i < size / sizeof(uint64_t); i++) {
uint64_t block;
block = src[i];
block = rol(block ^ kwn, (uint8_t)kwn);
block = __builtin_bswap64(block ^ kdbe) ^ kwa;
dst[i] = block;
}
}
static KDDEBUGGER_DATA64 *get_kdbg(uint64_t KernBase, struct pdb_reader *pdb,
struct va_space *vs, uint64_t KdDebuggerDataBlock)
{
const char OwnerTag[4] = "KDBG";
KDDEBUGGER_DATA64 *kdbg = NULL;
DBGKD_DEBUG_DATA_HEADER64 kdbg_hdr;
bool decode = false;
uint64_t kwn, kwa, KdpDataBlockEncoded;
if (va_space_rw(vs,
KdDebuggerDataBlock + offsetof(KDDEBUGGER_DATA64, Header),
&kdbg_hdr, sizeof(kdbg_hdr), 0)) {
eprintf("Failed to extract KDBG header\n");
return NULL;
}
if (memcmp(&kdbg_hdr.OwnerTag, OwnerTag, sizeof(OwnerTag))) {
uint64_t KiWaitNever, KiWaitAlways;
decode = true;
if (!SYM_RESOLVE(KernBase, pdb, KiWaitNever) ||
!SYM_RESOLVE(KernBase, pdb, KiWaitAlways) ||
!SYM_RESOLVE(KernBase, pdb, KdpDataBlockEncoded)) {
return NULL;
}
if (va_space_rw(vs, KiWaitNever, &kwn, sizeof(kwn), 0) ||
va_space_rw(vs, KiWaitAlways, &kwa, sizeof(kwa), 0)) {
return NULL;
}
printf("[KiWaitNever] = 0x%016"PRIx64"\n", kwn);
printf("[KiWaitAlways] = 0x%016"PRIx64"\n", kwa);
/*
* If KDBG header can be decoded, KDBG size is available
* and entire KDBG can be decoded.
*/
printf("Decoding KDBG header...\n");
kdbg_decode((uint64_t *)&kdbg_hdr, (uint64_t *)&kdbg_hdr,
sizeof(kdbg_hdr), kwn, kwa, KdpDataBlockEncoded);
printf("Owner tag is \'%.4s\'\n", (char *)&kdbg_hdr.OwnerTag);
if (memcmp(&kdbg_hdr.OwnerTag, OwnerTag, sizeof(OwnerTag))) {
eprintf("Failed to decode KDBG header\n");
return NULL;
}
}
kdbg = malloc(kdbg_hdr.Size);
if (!kdbg) {
return NULL;
}
if (va_space_rw(vs, KdDebuggerDataBlock, kdbg, kdbg_hdr.Size, 0)) {
eprintf("Failed to extract entire KDBG\n");
return NULL;
}
if (!decode) {
return kdbg;
}
printf("Decoding KdDebuggerDataBlock...\n");
kdbg_decode((uint64_t *)kdbg, (uint64_t *)kdbg, kdbg_hdr.Size,
kwn, kwa, KdpDataBlockEncoded);
va_space_rw(vs, KdDebuggerDataBlock, kdbg, kdbg_hdr.Size, 1);
return kdbg;
}
static void win_context_init_from_qemu_cpu_state(WinContext *ctx,
QEMUCPUState *s)
{
WinContext win_ctx = (WinContext){
.ContextFlags = WIN_CTX_X64 | WIN_CTX_INT | WIN_CTX_SEG | WIN_CTX_CTL,
.MxCsr = INITIAL_MXCSR,
.SegCs = s->cs.selector,
.SegSs = s->ss.selector,
.SegDs = s->ds.selector,
.SegEs = s->es.selector,
.SegFs = s->fs.selector,
.SegGs = s->gs.selector,
.EFlags = (uint32_t)s->rflags,
.Rax = s->rax,
.Rbx = s->rbx,
.Rcx = s->rcx,
.Rdx = s->rdx,
.Rsp = s->rsp,
.Rbp = s->rbp,
.Rsi = s->rsi,
.Rdi = s->rdi,
.R8 = s->r8,
.R9 = s->r9,
.R10 = s->r10,
.R11 = s->r11,
.R12 = s->r12,
.R13 = s->r13,
.R14 = s->r14,
.R15 = s->r15,
.Rip = s->rip,
.FltSave = {
.MxCsr = INITIAL_MXCSR,
},
};
*ctx = win_ctx;
}
/*
* Finds paging-structure hierarchy base,
* if previously set doesn't give access to kernel structures
*/
static int fix_dtb(struct va_space *vs, QEMU_Elf *qe)
{
/*
* Firstly, test previously set DTB.
*/
if (va_space_resolve(vs, SharedUserData)) {
return 0;
}
/*
* Secondly, find CPU which run system task.
*/
size_t i;
for (i = 0; i < qe->state_nr; i++) {
QEMUCPUState *s = qe->state[i];
if (is_system(s)) {
va_space_set_dtb(vs, s->cr[3]);
printf("DTB 0x%016"PRIx64" has been found from CPU #%zu"
" as system task CR3\n", vs->dtb, i);
return !(va_space_resolve(vs, SharedUserData));
}
}
/*
* Thirdly, use KERNEL_GS_BASE from CPU #0 as PRCB address and
* CR3 as [Prcb+0x7000]
*/
if (qe->has_kernel_gs_base) {
QEMUCPUState *s = qe->state[0];
uint64_t Prcb = s->kernel_gs_base;
uint64_t *cr3 = va_space_resolve(vs, Prcb + 0x7000);
if (!cr3) {
return 1;
}
va_space_set_dtb(vs, *cr3);
printf("DirectoryTableBase = 0x%016"PRIx64" has been found from CPU #0"
" as interrupt handling CR3\n", vs->dtb);
return !(va_space_resolve(vs, SharedUserData));
}
return 1;
}
static int fill_header(WinDumpHeader64 *hdr, struct pa_space *ps,
struct va_space *vs, uint64_t KdDebuggerDataBlock,
KDDEBUGGER_DATA64 *kdbg, uint64_t KdVersionBlock, int nr_cpus)
{
uint32_t *suite_mask = va_space_resolve(vs, SharedUserData +
KUSD_OFFSET_SUITE_MASK);
int32_t *product_type = va_space_resolve(vs, SharedUserData +
KUSD_OFFSET_PRODUCT_TYPE);
DBGKD_GET_VERSION64 kvb;
WinDumpHeader64 h;
size_t i;
QEMU_BUILD_BUG_ON(KUSD_OFFSET_SUITE_MASK >= ELF2DMP_PAGE_SIZE);
QEMU_BUILD_BUG_ON(KUSD_OFFSET_PRODUCT_TYPE >= ELF2DMP_PAGE_SIZE);
if (!suite_mask || !product_type) {
return 1;
}
if (va_space_rw(vs, KdVersionBlock, &kvb, sizeof(kvb), 0)) {
eprintf("Failed to extract KdVersionBlock\n");
return 1;
}
h = (WinDumpHeader64) {
.Signature = "PAGE",
.ValidDump = "DU64",
.MajorVersion = kvb.MajorVersion,
.MinorVersion = kvb.MinorVersion,
.DirectoryTableBase = vs->dtb,
.PfnDatabase = kdbg->MmPfnDatabase,
.PsLoadedModuleList = kdbg->PsLoadedModuleList,
.PsActiveProcessHead = kdbg->PsActiveProcessHead,
.MachineImageType = kvb.MachineType,
.NumberProcessors = nr_cpus,
.BugcheckCode = LIVE_SYSTEM_DUMP,
.KdDebuggerDataBlock = KdDebuggerDataBlock,
.DumpType = 1,
.Comment = "Hello from elf2dmp!",
.SuiteMask = *suite_mask,
.ProductType = *product_type,
.SecondaryDataState = kvb.KdSecondaryVersion,
.PhysicalMemoryBlock = (WinDumpPhyMemDesc64) {
.NumberOfRuns = ps->block_nr,
},
.RequiredDumpSpace = sizeof(h),
};
for (i = 0; i < ps->block_nr; i++) {
h.PhysicalMemoryBlock.NumberOfPages += ps->block[i].size / ELF2DMP_PAGE_SIZE;
h.PhysicalMemoryBlock.Run[i] = (WinDumpPhyMemRun64) {
.BasePage = ps->block[i].paddr / ELF2DMP_PAGE_SIZE,
.PageCount = ps->block[i].size / ELF2DMP_PAGE_SIZE,
};
}
h.RequiredDumpSpace += h.PhysicalMemoryBlock.NumberOfPages << ELF2DMP_PAGE_BITS;
*hdr = h;
return 0;
}
static int fill_context(KDDEBUGGER_DATA64 *kdbg,
struct va_space *vs, QEMU_Elf *qe)
{
int i;
for (i = 0; i < qe->state_nr; i++) {
uint64_t Prcb;
uint64_t Context;
WinContext ctx;
QEMUCPUState *s = qe->state[i];
if (va_space_rw(vs, kdbg->KiProcessorBlock + sizeof(Prcb) * i,
&Prcb, sizeof(Prcb), 0)) {
eprintf("Failed to read CPU #%d PRCB location\n", i);
return 1;
}
if (va_space_rw(vs, Prcb + kdbg->OffsetPrcbContext,
&Context, sizeof(Context), 0)) {
eprintf("Failed to read CPU #%d ContextFrame location\n", i);
return 1;
}
printf("Filling context for CPU #%d...\n", i);
win_context_init_from_qemu_cpu_state(&ctx, s);
if (va_space_rw(vs, Context, &ctx, sizeof(ctx), 1)) {
eprintf("Failed to fill CPU #%d context\n", i);
return 1;
}
}
return 0;
}
static int write_dump(struct pa_space *ps,
WinDumpHeader64 *hdr, const char *name)
{
FILE *dmp_file = fopen(name, "wb");
size_t i;
if (!dmp_file) {
eprintf("Failed to open output file \'%s\'\n", name);
return 1;
}
printf("Writing header to file...\n");
if (fwrite(hdr, sizeof(*hdr), 1, dmp_file) != 1) {
eprintf("Failed to write dump header\n");
fclose(dmp_file);
return 1;
}
for (i = 0; i < ps->block_nr; i++) {
struct pa_block *b = &ps->block[i];
printf("Writing block #%zu/%zu to file...\n", i, ps->block_nr);
if (fwrite(b->addr, b->size, 1, dmp_file) != 1) {
eprintf("Failed to write dump header\n");
fclose(dmp_file);
return 1;
}
}
return fclose(dmp_file);
}
static int pe_get_pdb_symstore_hash(uint64_t base, void *start_addr,
char *hash, struct va_space *vs)
{
const char e_magic[2] = "MZ";
const char Signature[4] = "PE\0\0";
const char sign_rsds[4] = "RSDS";
IMAGE_DOS_HEADER *dos_hdr = start_addr;
IMAGE_NT_HEADERS64 nt_hdrs;
IMAGE_FILE_HEADER *file_hdr = &nt_hdrs.FileHeader;
IMAGE_OPTIONAL_HEADER64 *opt_hdr = &nt_hdrs.OptionalHeader;
IMAGE_DATA_DIRECTORY *data_dir = nt_hdrs.OptionalHeader.DataDirectory;
IMAGE_DEBUG_DIRECTORY debug_dir;
OMFSignatureRSDS rsds;
char *pdb_name;
size_t pdb_name_sz;
size_t i;
QEMU_BUILD_BUG_ON(sizeof(*dos_hdr) >= ELF2DMP_PAGE_SIZE);
if (memcmp(&dos_hdr->e_magic, e_magic, sizeof(e_magic))) {
return 1;
}
if (va_space_rw(vs, base + dos_hdr->e_lfanew,
&nt_hdrs, sizeof(nt_hdrs), 0)) {
return 1;
}
if (memcmp(&nt_hdrs.Signature, Signature, sizeof(Signature)) ||
file_hdr->Machine != 0x8664 || opt_hdr->Magic != 0x020b) {
return 1;
}
printf("Debug Directory RVA = 0x%08"PRIx32"\n",
(uint32_t)data_dir[IMAGE_FILE_DEBUG_DIRECTORY].VirtualAddress);
if (va_space_rw(vs,
base + data_dir[IMAGE_FILE_DEBUG_DIRECTORY].VirtualAddress,
&debug_dir, sizeof(debug_dir), 0)) {
return 1;
}
if (debug_dir.Type != IMAGE_DEBUG_TYPE_CODEVIEW) {
return 1;
}
if (va_space_rw(vs,
base + debug_dir.AddressOfRawData,
&rsds, sizeof(rsds), 0)) {
return 1;
}
printf("CodeView signature is \'%.4s\'\n", rsds.Signature);
if (memcmp(&rsds.Signature, sign_rsds, sizeof(sign_rsds))) {
return 1;
}
pdb_name_sz = debug_dir.SizeOfData - sizeof(rsds);
pdb_name = malloc(pdb_name_sz);
if (!pdb_name) {
return 1;
}
if (va_space_rw(vs, base + debug_dir.AddressOfRawData +
offsetof(OMFSignatureRSDS, name), pdb_name, pdb_name_sz, 0)) {
free(pdb_name);
return 1;
}
printf("PDB name is \'%s\', \'%s\' expected\n", pdb_name, PDB_NAME);
if (strcmp(pdb_name, PDB_NAME)) {
eprintf("Unexpected PDB name, it seems the kernel isn't found\n");
free(pdb_name);
return 1;
}
free(pdb_name);
sprintf(hash, "%.08x%.04x%.04x%.02x%.02x", rsds.guid.a, rsds.guid.b,
rsds.guid.c, rsds.guid.d[0], rsds.guid.d[1]);
hash += 20;
for (i = 0; i < 6; i++, hash += 2) {
sprintf(hash, "%.02x", rsds.guid.e[i]);
}
sprintf(hash, "%.01x", rsds.age);
return 0;
}
int main(int argc, char *argv[])
{
int err = 0;
QEMU_Elf qemu_elf;
struct pa_space ps;
struct va_space vs;
QEMUCPUState *state;
idt_desc_t first_idt_desc;
uint64_t KernBase;
void *nt_start_addr = NULL;
WinDumpHeader64 header;
char pdb_hash[34];
char pdb_url[] = SYM_URL_BASE PDB_NAME
"/0123456789ABCDEF0123456789ABCDEFx/" PDB_NAME;
struct pdb_reader pdb;
uint64_t KdDebuggerDataBlock;
KDDEBUGGER_DATA64 *kdbg;
uint64_t KdVersionBlock;
if (argc != 3) {
eprintf("usage:\n\t%s elf_file dmp_file\n", argv[0]);
return 1;
}
if (QEMU_Elf_init(&qemu_elf, argv[1])) {
eprintf("Failed to initialize QEMU ELF dump\n");
return 1;
}
if (pa_space_create(&ps, &qemu_elf)) {
eprintf("Failed to initialize physical address space\n");
err = 1;
goto out_elf;
}
state = qemu_elf.state[0];
printf("CPU #0 CR3 is 0x%016"PRIx64"\n", state->cr[3]);
va_space_create(&vs, &ps, state->cr[3]);
if (fix_dtb(&vs, &qemu_elf)) {
eprintf("Failed to find paging base\n");
err = 1;
goto out_elf;
}
printf("CPU #0 IDT is at 0x%016"PRIx64"\n", state->idt.base);
if (va_space_rw(&vs, state->idt.base,
&first_idt_desc, sizeof(first_idt_desc), 0)) {
eprintf("Failed to get CPU #0 IDT[0]\n");
err = 1;
goto out_ps;
}
printf("CPU #0 IDT[0] -> 0x%016"PRIx64"\n", idt_desc_addr(first_idt_desc));
KernBase = idt_desc_addr(first_idt_desc) & ~(ELF2DMP_PAGE_SIZE - 1);
printf("Searching kernel downwards from 0x%016"PRIx64"...\n", KernBase);
for (; KernBase >= 0xfffff78000000000; KernBase -= ELF2DMP_PAGE_SIZE) {
nt_start_addr = va_space_resolve(&vs, KernBase);
if (!nt_start_addr) {
continue;
}
if (*(uint16_t *)nt_start_addr == 0x5a4d) { /* MZ */
break;
}
}
if (!nt_start_addr) {
eprintf("Failed to find NT kernel image\n");
err = 1;
goto out_ps;
}
printf("KernBase = 0x%016"PRIx64", signature is \'%.2s\'\n", KernBase,
(char *)nt_start_addr);
if (pe_get_pdb_symstore_hash(KernBase, nt_start_addr, pdb_hash, &vs)) {
eprintf("Failed to get PDB symbol store hash\n");
err = 1;
goto out_ps;
}
sprintf(pdb_url, "%s%s/%s/%s", SYM_URL_BASE, PDB_NAME, pdb_hash, PDB_NAME);
printf("PDB URL is %s\n", pdb_url);
if (download_url(PDB_NAME, pdb_url)) {
eprintf("Failed to download PDB file\n");
err = 1;
goto out_ps;
}
if (pdb_init_from_file(PDB_NAME, &pdb)) {
eprintf("Failed to initialize PDB reader\n");
err = 1;
goto out_pdb_file;
}
if (!SYM_RESOLVE(KernBase, &pdb, KdDebuggerDataBlock) ||
!SYM_RESOLVE(KernBase, &pdb, KdVersionBlock)) {
err = 1;
goto out_pdb;
}
kdbg = get_kdbg(KernBase, &pdb, &vs, KdDebuggerDataBlock);
if (!kdbg) {
err = 1;
goto out_pdb;
}
if (fill_header(&header, &ps, &vs, KdDebuggerDataBlock, kdbg,
KdVersionBlock, qemu_elf.state_nr)) {
err = 1;
goto out_kdbg;
}
if (fill_context(kdbg, &vs, &qemu_elf)) {
err = 1;
goto out_kdbg;
}
if (write_dump(&ps, &header, argv[2])) {
eprintf("Failed to save dump\n");
err = 1;
goto out_kdbg;
}
out_kdbg:
free(kdbg);
out_pdb:
pdb_exit(&pdb);
out_pdb_file:
unlink(PDB_NAME);
out_ps:
pa_space_destroy(&ps);
out_elf:
QEMU_Elf_exit(&qemu_elf);
return err;
}
