contrib/elf2dmp/main.c

   1 /*
   2  * Copyright (c) 2018 Virtuozzo International GmbH
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   5  *
   6  */
   7
   8 #include "qemu/osdep.h"
   9
  10 #include "err.h"
  11 #include "addrspace.h"
  12 #include "pe.h"
  13 #include "pdb.h"
  14 #include "kdbg.h"
  15 #include "download.h"
  16 #include "qemu/win_dump_defs.h"
  17
  18 #define SYM_URL_BASE    "https://msdl.microsoft.com/download/symbols/"
  19 #define PDB_NAME    "ntkrnlmp.pdb"
  20
  21 #define INITIAL_MXCSR   0x1f80
  22
  23 typedef struct idt_desc {
  24     uint16_t offset1;   /* offset bits 0..15 */
  25     uint16_t selector;
  26     uint8_t ist;
  27     uint8_t type_attr;
  28     uint16_t offset2;   /* offset bits 16..31 */
  29     uint32_t offset3;   /* offset bits 32..63 */
  30     uint32_t rsrvd;
  31 } __attribute__ ((packed)) idt_desc_t;
  32
  33 static uint64_t idt_desc_addr(idt_desc_t desc)
  34 {
  35     return (uint64_t)desc.offset1 | ((uint64_t)desc.offset2 << 16) |
  36           ((uint64_t)desc.offset3 << 32);
  37 }
  38
  39 static const uint64_t SharedUserData = 0xfffff78000000000;
  40
  41 #define KUSD_OFFSET_SUITE_MASK 0x2d0
  42 #define KUSD_OFFSET_PRODUCT_TYPE 0x264
  43
  44 #define SYM_RESOLVE(base, r, s) ((s = pdb_resolve(base, r, #s)),\
  45     s ? printf(#s" = 0x%016"PRIx64"\n", s) :\
  46     eprintf("Failed to resolve "#s"\n"), s)
  47
  48 static uint64_t rol(uint64_t x, uint64_t y)
  49 {
  50     return (x << y) | (x >> (64 - y));
  51 }
  52
  53 /*
  54  * Decoding algorithm can be found in Volatility project
  55  */
  56 static void kdbg_decode(uint64_t *dst, uint64_t *src, size_t size,
  57         uint64_t kwn, uint64_t kwa, uint64_t kdbe)
  58 {
  59     size_t i;
  60     assert(size % sizeof(uint64_t) == 0);
  61     for (i = 0; i < size / sizeof(uint64_t); i++) {
  62         uint64_t block;
  63
  64         block = src[i];
  65         block = rol(block ^ kwn, (uint8_t)kwn);
  66         block = __builtin_bswap64(block ^ kdbe) ^ kwa;
  67         dst[i] = block;
  68     }
  69 }
  70
  71 static KDDEBUGGER_DATA64 *get_kdbg(uint64_t KernBase, struct pdb_reader *pdb,
  72         struct va_space *vs, uint64_t KdDebuggerDataBlock)
  73 {
  74     const char OwnerTag[4] = "KDBG";
  75     KDDEBUGGER_DATA64 *kdbg = NULL;
  76     DBGKD_DEBUG_DATA_HEADER64 kdbg_hdr;
  77     bool decode = false;
  78     uint64_t kwn, kwa, KdpDataBlockEncoded;
  79
  80     if (va_space_rw(vs,
  81                 KdDebuggerDataBlock + offsetof(KDDEBUGGER_DATA64, Header),
  82                 &kdbg_hdr, sizeof(kdbg_hdr), 0)) {
  83         eprintf("Failed to extract KDBG header\n");
  84         return NULL;
  85     }
  86
  87     if (memcmp(&kdbg_hdr.OwnerTag, OwnerTag, sizeof(OwnerTag))) {
  88         uint64_t KiWaitNever, KiWaitAlways;
  89
  90         decode = true;
  91
  92         if (!SYM_RESOLVE(KernBase, pdb, KiWaitNever) ||
  93                 !SYM_RESOLVE(KernBase, pdb, KiWaitAlways) ||
  94                 !SYM_RESOLVE(KernBase, pdb, KdpDataBlockEncoded)) {
  95             return NULL;
  96         }
  97
  98         if (va_space_rw(vs, KiWaitNever, &kwn, sizeof(kwn), 0) ||
  99                 va_space_rw(vs, KiWaitAlways, &kwa, sizeof(kwa), 0)) {
 100             return NULL;
 101         }
 102
 103         printf("[KiWaitNever] = 0x%016"PRIx64"\n", kwn);
 104         printf("[KiWaitAlways] = 0x%016"PRIx64"\n", kwa);
 105
 106         /*
 107          * If KDBG header can be decoded, KDBG size is available
 108          * and entire KDBG can be decoded.
 109          */
 110         printf("Decoding KDBG header...\n");
 111         kdbg_decode((uint64_t *)&kdbg_hdr, (uint64_t *)&kdbg_hdr,
 112                 sizeof(kdbg_hdr), kwn, kwa, KdpDataBlockEncoded);
 113
 114         printf("Owner tag is \'%.4s\'\n", (char *)&kdbg_hdr.OwnerTag);
 115         if (memcmp(&kdbg_hdr.OwnerTag, OwnerTag, sizeof(OwnerTag))) {
 116             eprintf("Failed to decode KDBG header\n");
 117             return NULL;
 118         }
 119     }
 120
 121     kdbg = malloc(kdbg_hdr.Size);
 122     if (!kdbg) {
 123         return NULL;
 124     }
 125
 126     if (va_space_rw(vs, KdDebuggerDataBlock, kdbg, kdbg_hdr.Size, 0)) {
 127         eprintf("Failed to extract entire KDBG\n");
 128         return NULL;
 129     }
 130
 131     if (!decode) {
 132         return kdbg;
 133     }
 134
 135     printf("Decoding KdDebuggerDataBlock...\n");
 136     kdbg_decode((uint64_t *)kdbg, (uint64_t *)kdbg, kdbg_hdr.Size,
 137                 kwn, kwa, KdpDataBlockEncoded);
 138
 139     va_space_rw(vs, KdDebuggerDataBlock, kdbg, kdbg_hdr.Size, 1);
 140
 141     return kdbg;
 142 }
 143
 144 static void win_context_init_from_qemu_cpu_state(WinContext *ctx,
 145         QEMUCPUState *s)
 146 {
 147     WinContext win_ctx = (WinContext){
 148         .ContextFlags = WIN_CTX_X64 | WIN_CTX_INT | WIN_CTX_SEG | WIN_CTX_CTL,
 149         .MxCsr = INITIAL_MXCSR,
 150
 151         .SegCs = s->cs.selector,
 152         .SegSs = s->ss.selector,
 153         .SegDs = s->ds.selector,
 154         .SegEs = s->es.selector,
 155         .SegFs = s->fs.selector,
 156         .SegGs = s->gs.selector,
 157         .EFlags = (uint32_t)s->rflags,
 158
 159         .Rax = s->rax,
 160         .Rbx = s->rbx,
 161         .Rcx = s->rcx,
 162         .Rdx = s->rdx,
 163         .Rsp = s->rsp,
 164         .Rbp = s->rbp,
 165         .Rsi = s->rsi,
 166         .Rdi = s->rdi,
 167         .R8  = s->r8,
 168         .R9  = s->r9,
 169         .R10 = s->r10,
 170         .R11 = s->r11,
 171         .R12 = s->r12,
 172         .R13 = s->r13,
 173         .R14 = s->r14,
 174         .R15 = s->r15,
 175
 176         .Rip = s->rip,
 177         .FltSave = {
 178             .MxCsr = INITIAL_MXCSR,
 179         },
 180     };
 181
 182     *ctx = win_ctx;
 183 }
 184
 185 /*
 186  * Finds paging-structure hierarchy base,
 187  * if previously set doesn't give access to kernel structures
 188  */
 189 static int fix_dtb(struct va_space *vs, QEMU_Elf *qe)
 190 {
 191     /*
 192      * Firstly, test previously set DTB.
 193      */
 194     if (va_space_resolve(vs, SharedUserData)) {
 195         return 0;
 196     }
 197
 198     /*
 199      * Secondly, find CPU which run system task.
 200      */
 201     size_t i;
 202     for (i = 0; i < qe->state_nr; i++) {
 203         QEMUCPUState *s = qe->state[i];
 204
 205         if (is_system(s)) {
 206             va_space_set_dtb(vs, s->cr[3]);
 207             printf("DTB 0x%016"PRIx64" has been found from CPU #%zu"
 208                     " as system task CR3\n", vs->dtb, i);
 209             return !(va_space_resolve(vs, SharedUserData));
 210         }
 211     }
 212
 213     /*
 214      * Thirdly, use KERNEL_GS_BASE from CPU #0 as PRCB address and
 215      * CR3 as [Prcb+0x7000]
 216      */
 217     if (qe->has_kernel_gs_base) {
 218         QEMUCPUState *s = qe->state[0];
 219         uint64_t Prcb = s->kernel_gs_base;
 220         uint64_t *cr3 = va_space_resolve(vs, Prcb + 0x7000);
 221
 222         if (!cr3) {
 223             return 1;
 224         }
 225
 226         va_space_set_dtb(vs, *cr3);
 227         printf("DirectoryTableBase = 0x%016"PRIx64" has been found from CPU #0"
 228                 " as interrupt handling CR3\n", vs->dtb);
 229         return !(va_space_resolve(vs, SharedUserData));
 230     }
 231
 232     return 1;
 233 }
 234
 235 static int fill_header(WinDumpHeader64 *hdr, struct pa_space *ps,
 236         struct va_space *vs, uint64_t KdDebuggerDataBlock,
 237         KDDEBUGGER_DATA64 *kdbg, uint64_t KdVersionBlock, int nr_cpus)
 238 {
 239     uint32_t *suite_mask = va_space_resolve(vs, SharedUserData +
 240             KUSD_OFFSET_SUITE_MASK);
 241     int32_t *product_type = va_space_resolve(vs, SharedUserData +
 242             KUSD_OFFSET_PRODUCT_TYPE);
 243     DBGKD_GET_VERSION64 kvb;
 244     WinDumpHeader64 h;
 245     size_t i;
 246
 247     QEMU_BUILD_BUG_ON(KUSD_OFFSET_SUITE_MASK >= PAGE_SIZE);
 248     QEMU_BUILD_BUG_ON(KUSD_OFFSET_PRODUCT_TYPE >= PAGE_SIZE);
 249
 250     if (!suite_mask || !product_type) {
 251         return 1;
 252     }
 253
 254     if (va_space_rw(vs, KdVersionBlock, &kvb, sizeof(kvb), 0)) {
 255         eprintf("Failed to extract KdVersionBlock\n");
 256         return 1;
 257     }
 258
 259     h = (WinDumpHeader64) {
 260         .Signature = "PAGE",
 261         .ValidDump = "DU64",
 262         .MajorVersion = kvb.MajorVersion,
 263         .MinorVersion = kvb.MinorVersion,
 264         .DirectoryTableBase = vs->dtb,
 265         .PfnDatabase = kdbg->MmPfnDatabase,
 266         .PsLoadedModuleList = kdbg->PsLoadedModuleList,
 267         .PsActiveProcessHead = kdbg->PsActiveProcessHead,
 268         .MachineImageType = kvb.MachineType,
 269         .NumberProcessors = nr_cpus,
 270         .BugcheckCode = LIVE_SYSTEM_DUMP,
 271         .KdDebuggerDataBlock = KdDebuggerDataBlock,
 272         .DumpType = 1,
 273         .Comment = "Hello from elf2dmp!",
 274         .SuiteMask = *suite_mask,
 275         .ProductType = *product_type,
 276         .SecondaryDataState = kvb.KdSecondaryVersion,
 277         .PhysicalMemoryBlock = (WinDumpPhyMemDesc64) {
 278             .NumberOfRuns = ps->block_nr,
 279         },
 280         .RequiredDumpSpace = sizeof(h),
 281     };
 282
 283     for (i = 0; i < ps->block_nr; i++) {
 284         h.PhysicalMemoryBlock.NumberOfPages += ps->block[i].size / PAGE_SIZE;
 285         h.PhysicalMemoryBlock.Run[i] = (WinDumpPhyMemRun64) {
 286             .BasePage = ps->block[i].paddr / PAGE_SIZE,
 287             .PageCount = ps->block[i].size / PAGE_SIZE,
 288         };
 289     }
 290
 291     h.RequiredDumpSpace += h.PhysicalMemoryBlock.NumberOfPages << PAGE_BITS;
 292
 293     *hdr = h;
 294
 295     return 0;
 296 }
 297
 298 static int fill_context(KDDEBUGGER_DATA64 *kdbg,
 299         struct va_space *vs, QEMU_Elf *qe)
 300 {
 301         int i;
 302     for (i = 0; i < qe->state_nr; i++) {
 303         uint64_t Prcb;
 304         uint64_t Context;
 305         WinContext ctx;
 306         QEMUCPUState *s = qe->state[i];
 307
 308         if (va_space_rw(vs, kdbg->KiProcessorBlock + sizeof(Prcb) * i,
 309                     &Prcb, sizeof(Prcb), 0)) {
 310             eprintf("Failed to read CPU #%d PRCB location\n", i);
 311             return 1;
 312         }
 313
 314         if (va_space_rw(vs, Prcb + kdbg->OffsetPrcbContext,
 315                     &Context, sizeof(Context), 0)) {
 316             eprintf("Failed to read CPU #%d ContextFrame location\n", i);
 317             return 1;
 318         }
 319
 320         printf("Filling context for CPU #%d...\n", i);
 321         win_context_init_from_qemu_cpu_state(&ctx, s);
 322
 323         if (va_space_rw(vs, Context, &ctx, sizeof(ctx), 1)) {
 324             eprintf("Failed to fill CPU #%d context\n", i);
 325             return 1;
 326         }
 327     }
 328
 329     return 0;
 330 }
 331
 332 static int write_dump(struct pa_space *ps,
 333         WinDumpHeader64 *hdr, const char *name)
 334 {
 335     FILE *dmp_file = fopen(name, "wb");
 336     size_t i;
 337
 338     if (!dmp_file) {
 339         eprintf("Failed to open output file \'%s\'\n", name);
 340         return 1;
 341     }
 342
 343     printf("Writing header to file...\n");
 344
 345     if (fwrite(hdr, sizeof(*hdr), 1, dmp_file) != 1) {
 346         eprintf("Failed to write dump header\n");
 347         fclose(dmp_file);
 348         return 1;
 349     }
 350
 351     for (i = 0; i < ps->block_nr; i++) {
 352         struct pa_block *b = &ps->block[i];
 353
 354         printf("Writing block #%zu/%zu to file...\n", i, ps->block_nr);
 355         if (fwrite(b->addr, b->size, 1, dmp_file) != 1) {
 356             eprintf("Failed to write dump header\n");
 357             fclose(dmp_file);
 358             return 1;
 359         }
 360     }
 361
 362     return fclose(dmp_file);
 363 }
 364
 365 static int pe_get_pdb_symstore_hash(uint64_t base, void *start_addr,
 366         char *hash, struct va_space *vs)
 367 {
 368     const char e_magic[2] = "MZ";
 369     const char Signature[4] = "PE\0\0";
 370     const char sign_rsds[4] = "RSDS";
 371     IMAGE_DOS_HEADER *dos_hdr = start_addr;
 372     IMAGE_NT_HEADERS64 nt_hdrs;
 373     IMAGE_FILE_HEADER *file_hdr = &nt_hdrs.FileHeader;
 374     IMAGE_OPTIONAL_HEADER64 *opt_hdr = &nt_hdrs.OptionalHeader;
 375     IMAGE_DATA_DIRECTORY *data_dir = nt_hdrs.OptionalHeader.DataDirectory;
 376     IMAGE_DEBUG_DIRECTORY debug_dir;
 377     OMFSignatureRSDS rsds;
 378     char *pdb_name;
 379     size_t pdb_name_sz;
 380     size_t i;
 381
 382     QEMU_BUILD_BUG_ON(sizeof(*dos_hdr) >= PAGE_SIZE);
 383
 384     if (memcmp(&dos_hdr->e_magic, e_magic, sizeof(e_magic))) {
 385         return 1;
 386     }
 387
 388     if (va_space_rw(vs, base + dos_hdr->e_lfanew,
 389                 &nt_hdrs, sizeof(nt_hdrs), 0)) {
 390         return 1;
 391     }
 392
 393     if (memcmp(&nt_hdrs.Signature, Signature, sizeof(Signature)) ||
 394             file_hdr->Machine != 0x8664 || opt_hdr->Magic != 0x020b) {
 395         return 1;
 396     }
 397
 398     printf("Debug Directory RVA = 0x%08"PRIx32"\n",
 399             (uint32_t)data_dir[IMAGE_FILE_DEBUG_DIRECTORY].VirtualAddress);
 400
 401     if (va_space_rw(vs,
 402                 base + data_dir[IMAGE_FILE_DEBUG_DIRECTORY].VirtualAddress,
 403                 &debug_dir, sizeof(debug_dir), 0)) {
 404         return 1;
 405     }
 406
 407     if (debug_dir.Type != IMAGE_DEBUG_TYPE_CODEVIEW) {
 408         return 1;
 409     }
 410
 411     if (va_space_rw(vs,
 412                 base + debug_dir.AddressOfRawData,
 413                 &rsds, sizeof(rsds), 0)) {
 414         return 1;
 415     }
 416
 417     printf("CodeView signature is \'%.4s\'\n", rsds.Signature);
 418
 419     if (memcmp(&rsds.Signature, sign_rsds, sizeof(sign_rsds))) {
 420         return 1;
 421     }
 422
 423     pdb_name_sz = debug_dir.SizeOfData - sizeof(rsds);
 424     pdb_name = malloc(pdb_name_sz);
 425     if (!pdb_name) {
 426         return 1;
 427     }
 428
 429     if (va_space_rw(vs, base + debug_dir.AddressOfRawData +
 430                 offsetof(OMFSignatureRSDS, name), pdb_name, pdb_name_sz, 0)) {
 431         free(pdb_name);
 432         return 1;
 433     }
 434
 435     printf("PDB name is \'%s\', \'%s\' expected\n", pdb_name, PDB_NAME);
 436
 437     if (strcmp(pdb_name, PDB_NAME)) {
 438         eprintf("Unexpected PDB name, it seems the kernel isn't found\n");
 439         free(pdb_name);
 440         return 1;
 441     }
 442
 443     free(pdb_name);
 444
 445     sprintf(hash, "%.08x%.04x%.04x%.02x%.02x", rsds.guid.a, rsds.guid.b,
 446             rsds.guid.c, rsds.guid.d[0], rsds.guid.d[1]);
 447     hash += 20;
 448     for (i = 0; i < 6; i++, hash += 2) {
 449         sprintf(hash, "%.02x", rsds.guid.e[i]);
 450     }
 451
 452     sprintf(hash, "%.01x", rsds.age);
 453
 454     return 0;
 455 }
 456
 457 int main(int argc, char *argv[])
 458 {
 459     int err = 0;
 460     QEMU_Elf qemu_elf;
 461     struct pa_space ps;
 462     struct va_space vs;
 463     QEMUCPUState *state;
 464     idt_desc_t first_idt_desc;
 465     uint64_t KernBase;
 466     void *nt_start_addr = NULL;
 467     WinDumpHeader64 header;
 468     char pdb_hash[34];
 469     char pdb_url[] = SYM_URL_BASE PDB_NAME
 470         "/0123456789ABCDEF0123456789ABCDEFx/" PDB_NAME;
 471     struct pdb_reader pdb;
 472     uint64_t KdDebuggerDataBlock;
 473     KDDEBUGGER_DATA64 *kdbg;
 474     uint64_t KdVersionBlock;
 475
 476     if (argc != 3) {
 477         eprintf("usage:\n\t%s elf_file dmp_file\n", argv[0]);
 478         return 1;
 479     }
 480
 481     if (QEMU_Elf_init(&qemu_elf, argv[1])) {
 482         eprintf("Failed to initialize QEMU ELF dump\n");
 483         return 1;
 484     }
 485
 486     if (pa_space_create(&ps, &qemu_elf)) {
 487         eprintf("Failed to initialize physical address space\n");
 488         err = 1;
 489         goto out_elf;
 490     }
 491
 492     state = qemu_elf.state[0];
 493     printf("CPU #0 CR3 is 0x%016"PRIx64"\n", state->cr[3]);
 494
 495     va_space_create(&vs, &ps, state->cr[3]);
 496     if (fix_dtb(&vs, &qemu_elf)) {
 497         eprintf("Failed to find paging base\n");
 498         err = 1;
 499         goto out_elf;
 500     }
 501
 502     printf("CPU #0 IDT is at 0x%016"PRIx64"\n", state->idt.base);
 503
 504     if (va_space_rw(&vs, state->idt.base,
 505                 &first_idt_desc, sizeof(first_idt_desc), 0)) {
 506         eprintf("Failed to get CPU #0 IDT[0]\n");
 507         err = 1;
 508         goto out_ps;
 509     }
 510     printf("CPU #0 IDT[0] -> 0x%016"PRIx64"\n", idt_desc_addr(first_idt_desc));
 511
 512     KernBase = idt_desc_addr(first_idt_desc) & ~(PAGE_SIZE - 1);
 513     printf("Searching kernel downwards from 0x%016"PRIx64"...\n", KernBase);
 514
 515     for (; KernBase >= 0xfffff78000000000; KernBase -= PAGE_SIZE) {
 516         nt_start_addr = va_space_resolve(&vs, KernBase);
 517         if (!nt_start_addr) {
 518             continue;
 519         }
 520
 521         if (*(uint16_t *)nt_start_addr == 0x5a4d) { /* MZ */
 522             break;
 523         }
 524     }
 525
 526     if (!nt_start_addr) {
 527         eprintf("Failed to find NT kernel image\n");
 528         err = 1;
 529         goto out_ps;
 530     }
 531
 532     printf("KernBase = 0x%016"PRIx64", signature is \'%.2s\'\n", KernBase,
 533             (char *)nt_start_addr);
 534
 535     if (pe_get_pdb_symstore_hash(KernBase, nt_start_addr, pdb_hash, &vs)) {
 536         eprintf("Failed to get PDB symbol store hash\n");
 537         err = 1;
 538         goto out_ps;
 539     }
 540
 541     sprintf(pdb_url, "%s%s/%s/%s", SYM_URL_BASE, PDB_NAME, pdb_hash, PDB_NAME);
 542     printf("PDB URL is %s\n", pdb_url);
 543
 544     if (download_url(PDB_NAME, pdb_url)) {
 545         eprintf("Failed to download PDB file\n");
 546         err = 1;
 547         goto out_ps;
 548     }
 549
 550     if (pdb_init_from_file(PDB_NAME, &pdb)) {
 551         eprintf("Failed to initialize PDB reader\n");
 552         err = 1;
 553         goto out_pdb_file;
 554     }
 555
 556     if (!SYM_RESOLVE(KernBase, &pdb, KdDebuggerDataBlock) ||
 557             !SYM_RESOLVE(KernBase, &pdb, KdVersionBlock)) {
 558         err = 1;
 559         goto out_pdb;
 560     }
 561
 562     kdbg = get_kdbg(KernBase, &pdb, &vs, KdDebuggerDataBlock);
 563     if (!kdbg) {
 564         err = 1;
 565         goto out_pdb;
 566     }
 567
 568     if (fill_header(&header, &ps, &vs, KdDebuggerDataBlock, kdbg,
 569             KdVersionBlock, qemu_elf.state_nr)) {
 570         err = 1;
 571         goto out_kdbg;
 572     }
 573
 574     if (fill_context(kdbg, &vs, &qemu_elf)) {
 575         err = 1;
 576         goto out_kdbg;
 577     }
 578
 579     if (write_dump(&ps, &header, argv[2])) {
 580         eprintf("Failed to save dump\n");
 581         err = 1;
 582         goto out_kdbg;
 583     }
 584
 585 out_kdbg:
 586     free(kdbg);
 587 out_pdb:
 588     pdb_exit(&pdb);
 589 out_pdb_file:
 590     unlink(PDB_NAME);
 591 out_ps:
 592     pa_space_destroy(&ps);
 593 out_elf:
 594     QEMU_Elf_exit(&qemu_elf);
 595
 596     return err;
 597 }