/* * 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"); free(kdbg); 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(WinContext64 *ctx, QEMUCPUState *s) { WinContext64 win_ctx = (WinContext64){ .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; WinContext64 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; }