From e8c36b131ac12832bb1d5de0e3a710733fca88ac Mon Sep 17 00:00:00 2001 From: Nick Shipp Date: Sun, 22 Apr 2018 18:32:50 -0400 Subject: Initial commit --- boot.s | 76 ++++++++++++++++ mkpe.c | 319 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 395 insertions(+) create mode 100644 boot.s create mode 100644 mkpe.c diff --git a/boot.s b/boot.s new file mode 100644 index 0000000..3f3457a --- /dev/null +++ b/boot.s @@ -0,0 +1,76 @@ +bits 64 + +section .text + org 0x0 + +_start: + ; EFI System Table magic + mov rax, 0x5453595320494249 + cmp rax, [rdx] + + mov rdi, 0x1 + jne fail ; Invalid magic + +; mov r8, rax +; add r8, 0x1c +; mov word [rax+0x10], 0xfff +; mov qword [rax+0x12], r8 +; +; xor rcx, rcx +;zero: +; mov qword [r8+rcx], 0x0 +; add rcx, 0x8 +; cmp rcx, 0xfff +; jle zero +; +; lea r8, [rel int] +; mov word [rax+0x1c], r8w ; offset_1 +; shr r8, 16 +; mov word [rax+0x1e], 0 ; selector +; mov byte [rax+0x20], 0 ; ist +; mov byte [rax+0x21], 0xff ; type_attr +; mov word [rax+0x22], r8w ; offset_2 +; shr r8, 16 +; mov dword [rax+0x24], r8d ; offset_3 +; mov dword [rax+0x28], 0 ; reserved, SBZ +; +; cli +; lidt [rax+16] +; sti + + ;int 0x0 + + push rbp + mov rbp, rsp + sub rsp, 0x30 + + mov rbx, rdx + +hello: + mov rcx, qword [rdx+0x40] ; arg0=ConOut + lea rdx, [rel msg] ; arg1=msg + call qword [rcx+0x8] ; OutputString + + mov rdi, 0x0 ; EFI_SUCCESS + +fail: ; error in rdi + mov rax, rdi + mov rsp, rbp + pop rbp + retn + +msg: db __utf16__ 'Hello, World',0xd,0,0xa,0,0,0 + +; int: +; lea rax, [rel end] +; mov rdx, qword [rax+8] +; +; mov rcx, qword [rdx+0x40] ; arg0=ConOut +; lea rdx, [rel err] ; arg1=err +; call qword [rcx+0x8] ; OutputString +; +; iretq + +align 0x20 + +end: diff --git a/mkpe.c b/mkpe.c new file mode 100644 index 0000000..9920895 --- /dev/null +++ b/mkpe.c @@ -0,0 +1,319 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + int16_t lastsize; + int16_t nblocks; + int16_t nreloc; + int16_t hdrsize; + int16_t minalloc; + int16_t maxalloc; + void *ss; // 2 byte value + void *sp; // 2 byte value + int16_t checksum; + void *ip; // 2 byte value + void *cs; // 2 byte value + int16_t relocpos; + int16_t noverlay; + int16_t reserved1[4]; + int16_t oem_id; + int16_t oem_info; + int16_t reserved2[10]; +*/ + +#define ROUND_UP(N, S) ((((N) + (S) - 1) / (S)) * (S)) + +struct DOS_Header { + char signature[2]; // {'M', 'Z'} + uint16_t e_cblp; // Bytes on last page of file + uint16_t e_cp; // Pages in file + uint16_t e_crlc; // Relocations + uint16_t e_cparhdr; // Size of header in paragraphs + uint16_t e_minalloc; // Minimum extra paragraphs needed + uint16_t e_maxalloc; // Maximum extra paragraphs needed + uint16_t e_ss; // Initial (relative) SS value + uint16_t e_sp; // Initial SP value + uint16_t e_csum; // Checksum + uint16_t e_ip; // Initial IP value + uint16_t e_cs; // Initial (relative) CS value + uint16_t e_lfarlc; // File address of relocation table + uint16_t e_ovno; // Overlay number + uint16_t e_res[4]; // Reserved words + uint16_t e_oemid; // OEM identifier (for e_oeminfo) + uint16_t e_oeminfo; // OEM information; e_oemid specific + uint16_t e_res2[10]; // Reserved words + int32_t e_lfanew; // Offset to the 'PE\0\0' signature relative to the beginning of the file +} __attribute__((packed)); + +struct PE_OpHdr { + uint16_t format; + char linker_ver_maj; + char linker_ver_min; + + uint32_t codesz; + uint32_t bsssz; + uint32_t datasz; + uint32_t entrypoint; + uint32_t codebase; + + uint64_t imagebase; + uint32_t sectalign; + uint32_t filealign; + uint16_t os_ver_maj; + uint16_t os_ver_min; + uint16_t img_ver_maj; + uint16_t img_ver_min; + uint16_t subs_ver_maj; + uint16_t subs_ver_min; + uint32_t win32_ver; + + uint32_t imagesz; + uint32_t hdrsz; + uint32_t cksum; + uint16_t subsystem; + uint16_t dllcharacteristics; + uint64_t stack_res; + uint64_t stack_commit; + uint64_t heap_res; + uint64_t heap_commit; + + uint32_t loader_flags; + uint32_t nr_rva_sz; +} __attribute__((packed)); + +struct PE_Header { + char signature[2]; + uint16_t fill0; + uint16_t arch; + uint16_t nr_sections; + uint32_t datetime; + uint32_t symtabptr; + uint32_t nr_symbols; + uint16_t ophdrsz; + uint16_t characteristics; + struct PE_OpHdr ophdr; +} __attribute__((packed)); + +struct PE_SecHdr { + char name[8]; + uint32_t virtsz; + uint32_t vaddr; + uint32_t rawsz; + uint32_t dataptr; + uint32_t relocptr; + uint32_t linenrptr; + uint16_t nr_reloc; + uint16_t nr_linenr; + uint32_t characteristics; +} __attribute__((packed)); + +struct PE_Reloc { + uint32_t offset; + uint32_t value; + char fill[0x20-0x8]; +} __attribute__((packed)); + +ssize_t +writeall(int fd, void *buf, size_t sz) +{ + ssize_t wr, ssz; + + ssz = (ssize_t) sz; + + while ((wr = write(fd, buf, sz)) != -1) { + if (wr == ssz) { + break; + } + + buf += wr; + ssz -= wr; + } + + return (wr); +} + +char * +readall(int fd, size_t *sz) +{ + char *data; + size_t cap, len; + ssize_t n; + int err; + + *sz = 0; + + cap = BUFSIZ; + len = 0; + data = malloc(cap); + + if (data == NULL) { + return (NULL); + } + + while ((n = read(fd, data+len, BUFSIZ)) >= 0) { + if (n == 0) { + break; + } + + len += n; + + if (len >= cap) { + cap += BUFSIZ; + data = realloc(data, cap); + } + } + if (n == -1) { + err = errno; + free(data); + errno = err; + return (NULL); + } + + *sz = len; + + return (data); +} + +int +main(int argc, char **argv) +{ + struct DOS_Header dhdr; + struct PE_Header phdr; + struct PE_SecHdr sect; + struct PE_Reloc relo; + uint32_t hdrsz; + int ifd, ofd, err; + char *code; + size_t codesz; + void *zero; + + assert(offsetof(struct DOS_Header, e_lfanew) == 0x3c); + + if (argc != 3) { + fprintf(stderr, "Usage: %s INPUT.BIN OUTPUT.BIN\n", argv[0]); + return (1); + } + + ifd = open(argv[1], O_RDONLY); + if (ifd < 0) { + err = errno; + perror(argv[1]); + return (err); + } + + ofd = open(argv[2], O_WRONLY|O_CREAT|O_TRUNC, + S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH); + + if (ofd < 0) { + err = errno; + perror(argv[2]); + close(ifd); + return (err); + } + + code = readall(ifd, &codesz); + if (code == NULL) { + err = errno; + perror("readall"); + close(ifd); + close(ofd); + return (err); + } + + memset(&dhdr, 0, sizeof(struct DOS_Header)); + memset(&phdr, 0, sizeof(struct PE_Header)); + memset(§, 0, sizeof(struct PE_SecHdr)); + memset(&relo, 0, sizeof(struct PE_Reloc)); + + dhdr.signature[0] = 'M'; + dhdr.signature[1] = 'Z'; + dhdr.e_lfanew = sizeof(struct DOS_Header); + + writeall(ofd, &dhdr, sizeof(struct DOS_Header)); + + phdr.signature[0] = 'P'; + phdr.signature[1] = 'E'; + phdr.arch = 0x8664; /* x86_64 */ + phdr.nr_sections = 2; /* text, reloc */ + phdr.nr_symbols = 1; + phdr.ophdrsz = sizeof(struct PE_OpHdr); + printf("phdr = %zu, ophdr = %zu\n", sizeof(struct PE_Header), sizeof(struct PE_OpHdr)); + phdr.characteristics = 0x206; + + phdr.ophdr.format = 0x20b; /* PE32+ (x64) */ + phdr.ophdr.linker_ver_maj = 0x02; + phdr.ophdr.linker_ver_min = 0x14; + phdr.ophdr.codebase = 0x200; + phdr.ophdr.sectalign = 0x20; + assert(phdr.ophdr.sectalign == sizeof(struct PE_Reloc)); + phdr.ophdr.filealign = 0x20; + phdr.ophdr.subsystem = 0xa; /* EFI Application */ + phdr.ophdr.nr_rva_sz = 0x0; + + assert(codesz <= (uint32_t)(~0)); + phdr.ophdr.codesz = (uint32_t) codesz; + printf("codesz = %u\n", phdr.ophdr.codesz); + + hdrsz = sizeof(struct DOS_Header) + + sizeof(struct PE_Header) + + phdr.nr_sections * sizeof(struct PE_SecHdr); + printf("hdrsz = %u\n", hdrsz); + /* round up to multiple of filealign */ + phdr.ophdr.hdrsz = ROUND_UP(hdrsz, phdr.ophdr.filealign);; + assert(phdr.ophdr.hdrsz % phdr.ophdr.filealign == 0); + printf("hdrsz = %u (aligned)\n", phdr.ophdr.hdrsz); + + phdr.ophdr.entrypoint = phdr.ophdr.hdrsz; + + phdr.ophdr.imagesz = phdr.ophdr.hdrsz + codesz + phdr.ophdr.sectalign; + printf("imagesz = %u\n", phdr.ophdr.imagesz); + assert(phdr.ophdr.imagesz % phdr.ophdr.sectalign == 0); + + writeall(ofd, &phdr, sizeof(struct PE_Header)); + + strcpy((char *)§.name, ".reloc"); + /* READ|DISCARDABLE|INITIALIZED */ + sect.characteristics = 0x42000040; + sect.virtsz = phdr.ophdr.sectalign; + sect.vaddr = phdr.ophdr.hdrsz + codesz; + sect.rawsz = phdr.ophdr.sectalign; + sect.dataptr = phdr.ophdr.hdrsz + codesz; + + relo.offset = sect.dataptr; + relo.value = 10; /* arbitrary number */ + + writeall(ofd, §, sizeof(struct PE_SecHdr)); + + memset(§, 0, sizeof(struct PE_SecHdr)); + strcpy((char *)§.name, ".text"); + /* READ|EXEC|ALIGN_16BYTES|CODE */ + sect.characteristics = 0x60500020; + sect.virtsz = ROUND_UP(codesz, phdr.ophdr.sectalign); + sect.vaddr = phdr.ophdr.hdrsz; + sect.rawsz = codesz; + sect.dataptr = phdr.ophdr.hdrsz; + + writeall(ofd, §, sizeof(struct PE_SecHdr)); + + if (phdr.ophdr.hdrsz - hdrsz) { + zero = calloc(1, phdr.ophdr.hdrsz - hdrsz); + writeall(ofd, zero, phdr.ophdr.hdrsz - hdrsz); + } + + writeall(ofd, code, codesz); + writeall(ofd, &relo, sizeof(struct PE_Reloc)); + + close(ofd); + close(ifd); + free(code); + + return (0); +} -- cgit v1.2.3-54-g00ecf