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post-process-pe.c
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post-process-pe.c
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// SPDX-License-Identifier: BSD-2-Clause-Patent
/*
* post-process-pe.c - fix up timestamps and checksums in broken PE files
* Copyright Peter Jones <[email protected]>
*/
#define _GNU_SOURCE 1
#include <err.h>
#include <fcntl.h>
#include <getopt.h>
#include <inttypes.h>
#include <limits.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#ifndef PAGE_SIZE
#define PAGE_SIZE 4096
#endif
static int verbosity;
#define ERROR 0
#define WARNING 1
#define INFO 2
#define NOISE 3
#define MIN_VERBOSITY ERROR
#define MAX_VERBOSITY NOISE
#define debug(level, ...) \
({ \
if (verbosity >= (level)) { \
printf("%s():%d: ", __func__, __LINE__); \
printf(__VA_ARGS__); \
} \
0; \
})
static bool set_nx_compat = false;
typedef uint8_t UINT8;
typedef uint16_t UINT16;
typedef uint32_t UINT32;
typedef uint64_t UINT64;
typedef uint16_t CHAR16;
typedef unsigned long UINTN;
typedef struct {
UINT32 Data1;
UINT16 Data2;
UINT16 Data3;
UINT8 Data4[8];
} EFI_GUID;
#include "include/peimage.h"
#if defined(__GNUC__) && defined(__GNUC_MINOR__)
#define GNUC_PREREQ(maj, min) \
((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
#else
#define GNUC_PREREQ(maj, min) 0
#endif
#if defined(__clang__) && defined(__clang_major__) && defined(__clang_minor__)
#define CLANG_PREREQ(maj, min) \
((__clang_major__ > (maj)) || \
(__clang_major__ == (maj) && __clang_minor__ >= (min)))
#else
#define CLANG_PREREQ(maj, min) 0
#endif
#if GNUC_PREREQ(5, 1) || CLANG_PREREQ(3, 8)
#define add(a0, a1, s) __builtin_add_overflow(a0, a1, s)
#define sub(s0, s1, d) __builtin_sub_overflow(s0, s1, d)
#define mul(f0, f1, p) __builtin_mul_overflow(f0, f1, p)
#else
#define add(a0, a1, s) \
({ \
(*s) = ((a0) + (a1)); \
0; \
})
#define sub(s0, s1, d) \
({ \
(*d) = ((s0) - (s1)); \
0; \
})
#define mul(f0, f1, p) \
({ \
(*p) = ((f0) * (f1)); \
0; \
})
#endif
#define div(d0, d1, q) \
({ \
unsigned int ret_ = ((d1) == 0); \
if (ret_ == 0) \
(*q) = ((d0) / (d1)); \
ret_; \
})
static int
image_is_64_bit(EFI_IMAGE_OPTIONAL_HEADER_UNION *PEHdr)
{
/* .Magic is the same offset in all cases */
if (PEHdr->Pe32Plus.OptionalHeader.Magic ==
EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC)
return 1;
return 0;
}
static void
load_pe(const char *const file, void *const data, const size_t datasize,
PE_COFF_LOADER_IMAGE_CONTEXT *ctx)
{
EFI_IMAGE_DOS_HEADER *DOSHdr = data;
EFI_IMAGE_OPTIONAL_HEADER_UNION *PEHdr = data;
size_t HeaderWithoutDataDir, SectionHeaderOffset, OptHeaderSize;
size_t FileAlignment = 0;
size_t sz0 = 0, sz1 = 0;
uintptr_t loc = 0;
debug(NOISE, "datasize:%zu sizeof(PEHdr->Pe32):%zu\n", datasize,
sizeof(PEHdr->Pe32));
if (datasize < sizeof(PEHdr->Pe32))
errx(1, "%s: Invalid image size %zu (%zu < %zu)", file,
datasize, datasize, sizeof(PEHdr->Pe32));
debug(NOISE,
"DOSHdr->e_magic:0x%02hx EFI_IMAGE_DOS_SIGNATURE:0x%02hx\n",
DOSHdr->e_magic, EFI_IMAGE_DOS_SIGNATURE);
if (DOSHdr->e_magic != EFI_IMAGE_DOS_SIGNATURE)
errx(1,
"%s: Invalid DOS header signature 0x%04hx (expected 0x%04hx)",
file, DOSHdr->e_magic, EFI_IMAGE_DOS_SIGNATURE);
debug(NOISE, "DOSHdr->e_lfanew:%u datasize:%zu\n", DOSHdr->e_lfanew,
datasize);
if (DOSHdr->e_lfanew >= datasize ||
add((uintptr_t)data, DOSHdr->e_lfanew, &loc))
errx(1, "%s: invalid pe header location", file);
ctx->PEHdr = PEHdr = (EFI_IMAGE_OPTIONAL_HEADER_UNION *)loc;
debug(NOISE, "PE signature:0x%04x EFI_IMAGE_NT_SIGNATURE:0x%04x\n",
PEHdr->Pe32.Signature, EFI_IMAGE_NT_SIGNATURE);
if (PEHdr->Pe32.Signature != EFI_IMAGE_NT_SIGNATURE)
errx(1, "%s: Unsupported image type", file);
if (image_is_64_bit(PEHdr)) {
debug(NOISE, "image is 64bit\n");
ctx->NumberOfRvaAndSizes =
PEHdr->Pe32Plus.OptionalHeader.NumberOfRvaAndSizes;
ctx->SizeOfHeaders =
PEHdr->Pe32Plus.OptionalHeader.SizeOfHeaders;
ctx->ImageSize = PEHdr->Pe32Plus.OptionalHeader.SizeOfImage;
ctx->SectionAlignment =
PEHdr->Pe32Plus.OptionalHeader.SectionAlignment;
FileAlignment = PEHdr->Pe32Plus.OptionalHeader.FileAlignment;
OptHeaderSize = sizeof(EFI_IMAGE_OPTIONAL_HEADER64);
} else {
debug(NOISE, "image is 32bit\n");
ctx->NumberOfRvaAndSizes =
PEHdr->Pe32.OptionalHeader.NumberOfRvaAndSizes;
ctx->SizeOfHeaders = PEHdr->Pe32.OptionalHeader.SizeOfHeaders;
ctx->ImageSize = (UINT64)PEHdr->Pe32.OptionalHeader.SizeOfImage;
ctx->SectionAlignment =
PEHdr->Pe32.OptionalHeader.SectionAlignment;
FileAlignment = PEHdr->Pe32.OptionalHeader.FileAlignment;
OptHeaderSize = sizeof(EFI_IMAGE_OPTIONAL_HEADER32);
}
if (FileAlignment % 2 != 0)
errx(1, "%s: Invalid file alignment %zu", file, FileAlignment);
if (FileAlignment == 0)
FileAlignment = 0x200;
if (ctx->SectionAlignment == 0)
ctx->SectionAlignment = PAGE_SIZE;
if (ctx->SectionAlignment < FileAlignment)
ctx->SectionAlignment = FileAlignment;
ctx->NumberOfSections = PEHdr->Pe32.FileHeader.NumberOfSections;
debug(NOISE,
"Number of RVAs:%"PRIu64" EFI_IMAGE_NUMBER_OF_DIRECTORY_ENTRIES:%d\n",
ctx->NumberOfRvaAndSizes, EFI_IMAGE_NUMBER_OF_DIRECTORY_ENTRIES);
if (EFI_IMAGE_NUMBER_OF_DIRECTORY_ENTRIES < ctx->NumberOfRvaAndSizes)
errx(1, "%s: invalid number of RVAs (%lu entries, max is %d)",
file, (unsigned long)ctx->NumberOfRvaAndSizes,
EFI_IMAGE_NUMBER_OF_DIRECTORY_ENTRIES);
if (mul(sizeof(EFI_IMAGE_DATA_DIRECTORY),
EFI_IMAGE_NUMBER_OF_DIRECTORY_ENTRIES, &sz0) ||
sub(OptHeaderSize, sz0, &HeaderWithoutDataDir) ||
sub(PEHdr->Pe32.FileHeader.SizeOfOptionalHeader,
HeaderWithoutDataDir, &sz0) ||
mul(ctx->NumberOfRvaAndSizes, sizeof(EFI_IMAGE_DATA_DIRECTORY),
&sz1) ||
(sz0 != sz1)) {
if (mul(sizeof(EFI_IMAGE_DATA_DIRECTORY),
EFI_IMAGE_NUMBER_OF_DIRECTORY_ENTRIES, &sz0))
debug(ERROR,
"sizeof(EFI_IMAGE_DATA_DIRECTORY) * EFI_IMAGE_NUMBER_OF_DIRECTORY_ENTRIES overflows\n");
else
debug(ERROR,
"sizeof(EFI_IMAGE_DATA_DIRECTORY) * EFI_IMAGE_NUMBER_OF_DIRECTORY_ENTRIES = %zu\n",
sz0);
if (sub(OptHeaderSize, sz0, &HeaderWithoutDataDir))
debug(ERROR,
"OptHeaderSize (%zu) - HeaderWithoutDataDir (%zu) overflows\n",
OptHeaderSize, HeaderWithoutDataDir);
else
debug(ERROR,
"OptHeaderSize (%zu) - HeaderWithoutDataDir (%zu) = %zu\n",
OptHeaderSize, sz0, HeaderWithoutDataDir);
if (sub(PEHdr->Pe32.FileHeader.SizeOfOptionalHeader,
HeaderWithoutDataDir, &sz0)) {
debug(ERROR,
"PEHdr->Pe32.FileHeader.SizeOfOptionalHeader (%d) - %zu overflows\n",
PEHdr->Pe32.FileHeader.SizeOfOptionalHeader,
HeaderWithoutDataDir);
} else {
debug(ERROR,
"PEHdr->Pe32.FileHeader.SizeOfOptionalHeader (%d)- %zu = %zu\n",
PEHdr->Pe32.FileHeader.SizeOfOptionalHeader,
HeaderWithoutDataDir, sz0);
}
if (mul(ctx->NumberOfRvaAndSizes,
sizeof(EFI_IMAGE_DATA_DIRECTORY), &sz1))
debug(ERROR,
"ctx->NumberOfRvaAndSizes (%ld) * sizeof(EFI_IMAGE_DATA_DIRECTORY) overflows\n",
(unsigned long)ctx->NumberOfRvaAndSizes);
else
debug(ERROR,
"ctx->NumberOfRvaAndSizes (%ld) * sizeof(EFI_IMAGE_DATA_DIRECTORY) = %zu\n",
(unsigned long)ctx->NumberOfRvaAndSizes, sz1);
debug(ERROR,
"space after image header:%zu data directory size:%zu\n",
sz0, sz1);
errx(1, "%s: image header overflows data directory", file);
}
if (add(DOSHdr->e_lfanew, sizeof(UINT32), &SectionHeaderOffset) ||
add(SectionHeaderOffset, sizeof(EFI_IMAGE_FILE_HEADER),
&SectionHeaderOffset) ||
add(SectionHeaderOffset,
PEHdr->Pe32.FileHeader.SizeOfOptionalHeader,
&SectionHeaderOffset)) {
debug(ERROR, "SectionHeaderOffset:%" PRIu32 " + %zu + %zu + %d",
DOSHdr->e_lfanew, sizeof(UINT32),
sizeof(EFI_IMAGE_FILE_HEADER),
PEHdr->Pe32.FileHeader.SizeOfOptionalHeader);
errx(1, "%s: SectionHeaderOffset would overflow", file);
}
if (sub(ctx->ImageSize, SectionHeaderOffset, &sz0) ||
div(sz0, EFI_IMAGE_SIZEOF_SECTION_HEADER, &sz0) ||
(sz0 <= ctx->NumberOfSections)) {
debug(ERROR, "(%" PRIu64 " - %zu) / %d > %d\n", ctx->ImageSize,
SectionHeaderOffset, EFI_IMAGE_SIZEOF_SECTION_HEADER,
ctx->NumberOfSections);
errx(1, "%s: image sections overflow image size", file);
}
if (sub(ctx->SizeOfHeaders, SectionHeaderOffset, &sz0) ||
div(sz0, EFI_IMAGE_SIZEOF_SECTION_HEADER, &sz0) ||
(sz0 < ctx->NumberOfSections)) {
debug(ERROR, "(%zu - %zu) / %d >= %d\n", (size_t)ctx->SizeOfHeaders,
SectionHeaderOffset, EFI_IMAGE_SIZEOF_SECTION_HEADER,
ctx->NumberOfSections);
errx(1, "%s: image sections overflow section headers", file);
}
if (sub((uintptr_t)PEHdr, (uintptr_t)data, &sz0) ||
add(sz0, sizeof(EFI_IMAGE_OPTIONAL_HEADER_UNION), &sz0) ||
(sz0 > datasize)) {
errx(1, "%s: PE Image size %zu > %zu", file, sz0, datasize);
}
if (PEHdr->Pe32.FileHeader.Characteristics & EFI_IMAGE_FILE_RELOCS_STRIPPED)
errx(1, "%s: Unsupported image - Relocations have been stripped", file);
if (image_is_64_bit(PEHdr)) {
ctx->ImageAddress = PEHdr->Pe32Plus.OptionalHeader.ImageBase;
ctx->EntryPoint =
PEHdr->Pe32Plus.OptionalHeader.AddressOfEntryPoint;
ctx->RelocDir = &PEHdr->Pe32Plus.OptionalHeader.DataDirectory
[EFI_IMAGE_DIRECTORY_ENTRY_BASERELOC];
ctx->SecDir = &PEHdr->Pe32Plus.OptionalHeader.DataDirectory
[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
} else {
ctx->ImageAddress = PEHdr->Pe32.OptionalHeader.ImageBase;
ctx->EntryPoint =
PEHdr->Pe32.OptionalHeader.AddressOfEntryPoint;
ctx->RelocDir = &PEHdr->Pe32.OptionalHeader.DataDirectory
[EFI_IMAGE_DIRECTORY_ENTRY_BASERELOC];
ctx->SecDir = &PEHdr->Pe32.OptionalHeader.DataDirectory
[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
}
if (add((uintptr_t)PEHdr, PEHdr->Pe32.FileHeader.SizeOfOptionalHeader,
&loc) ||
add(loc, sizeof(UINT32), &loc) ||
add(loc, sizeof(EFI_IMAGE_FILE_HEADER), &loc))
errx(1, "%s: invalid location for first section", file);
ctx->FirstSection = (EFI_IMAGE_SECTION_HEADER *)loc;
if (ctx->ImageSize < ctx->SizeOfHeaders)
errx(1,
"%s: Image size %"PRIu64" is smaller than header size %lu",
file, ctx->ImageSize, ctx->SizeOfHeaders);
if (sub((uintptr_t)ctx->SecDir, (uintptr_t)data, &sz0) ||
sub(datasize, sizeof(EFI_IMAGE_DATA_DIRECTORY), &sz1) ||
sz0 > sz1)
errx(1,
"%s: security direcory offset %zu past data directory at %zu",
file, sz0, sz1);
if (ctx->SecDir->VirtualAddress > datasize ||
(ctx->SecDir->VirtualAddress == datasize &&
ctx->SecDir->Size > 0))
errx(1, "%s: Security directory extends past end", file);
}
static void
set_dll_characteristics(PE_COFF_LOADER_IMAGE_CONTEXT *ctx)
{
uint16_t oldflags, newflags;
if (image_is_64_bit(ctx->PEHdr)) {
oldflags = ctx->PEHdr->Pe32Plus.OptionalHeader.DllCharacteristics;
} else {
oldflags = ctx->PEHdr->Pe32.OptionalHeader.DllCharacteristics;
}
if (set_nx_compat)
newflags = oldflags | EFI_IMAGE_DLLCHARACTERISTICS_NX_COMPAT;
else
newflags = oldflags & ~(uint16_t)EFI_IMAGE_DLLCHARACTERISTICS_NX_COMPAT;
if (oldflags == newflags)
return;
debug(INFO, "Updating DLL Characteristics from 0x%04hx to 0x%04hx\n",
oldflags, newflags);
if (image_is_64_bit(ctx->PEHdr)) {
ctx->PEHdr->Pe32Plus.OptionalHeader.DllCharacteristics = newflags;
} else {
ctx->PEHdr->Pe32.OptionalHeader.DllCharacteristics = newflags;
}
}
static void
fix_timestamp(PE_COFF_LOADER_IMAGE_CONTEXT *ctx)
{
uint32_t ts;
if (image_is_64_bit(ctx->PEHdr)) {
ts = ctx->PEHdr->Pe32Plus.FileHeader.TimeDateStamp;
} else {
ts = ctx->PEHdr->Pe32.FileHeader.TimeDateStamp;
}
if (ts != 0) {
debug(INFO, "Updating timestamp from 0x%08x to 0\n", ts);
if (image_is_64_bit(ctx->PEHdr)) {
ctx->PEHdr->Pe32Plus.FileHeader.TimeDateStamp = 0;
} else {
ctx->PEHdr->Pe32.FileHeader.TimeDateStamp = 0;
}
}
}
static void
fix_checksum(PE_COFF_LOADER_IMAGE_CONTEXT *ctx, void *map, size_t mapsize)
{
uint32_t old;
uint32_t checksum = 0;
uint16_t word;
uint8_t *data = map;
if (image_is_64_bit(ctx->PEHdr)) {
old = ctx->PEHdr->Pe32Plus.OptionalHeader.CheckSum;
ctx->PEHdr->Pe32Plus.OptionalHeader.CheckSum = 0;
} else {
old = ctx->PEHdr->Pe32.OptionalHeader.CheckSum;
ctx->PEHdr->Pe32.OptionalHeader.CheckSum = 0;
}
debug(NOISE, "old checksum was 0x%08x\n", old);
for (size_t i = 0; i < mapsize - 1; i += 2) {
word = (data[i + 1] << 8ul) | data[i];
checksum += word;
checksum = 0xffff & (checksum + (checksum >> 0x10));
}
debug(NOISE, "checksum = 0x%08x + 0x%08zx = 0x%08zx\n", checksum,
mapsize, checksum + mapsize);
checksum += mapsize;
if (checksum != old)
debug(INFO, "Updating checksum from 0x%08x to 0x%08x\n",
old, checksum);
if (image_is_64_bit(ctx->PEHdr)) {
ctx->PEHdr->Pe32Plus.OptionalHeader.CheckSum = checksum;
} else {
ctx->PEHdr->Pe32.OptionalHeader.CheckSum = checksum;
}
}
static void
handle_one(char *f)
{
int fd;
int rc;
struct stat statbuf;
size_t sz;
void *map;
int failed = 0;
PE_COFF_LOADER_IMAGE_CONTEXT ctx = { 0, 0 };
fd = open(f, O_RDWR | O_EXCL);
if (fd < 0)
err(1, "Could not open \"%s\"", f);
rc = fstat(fd, &statbuf);
if (rc < 0)
err(1, "Could not stat \"%s\"", f);
sz = statbuf.st_size;
map = mmap(NULL, sz, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (map == MAP_FAILED)
err(1, "Could not map \"%s\"", f);
load_pe(f, map, sz, &ctx);
set_dll_characteristics(&ctx);
fix_timestamp(&ctx);
fix_checksum(&ctx, map, sz);
rc = msync(map, sz, MS_SYNC);
if (rc < 0) {
warn("msync(%p, %zu, MS_SYNC) failed", map, sz);
failed = 1;
}
rc = munmap(map, sz);
if (rc < 0) {
warn("munmap(%p, %zu) failed", map, sz);
failed = 1;
}
rc = close(fd);
if (rc < 0) {
warn("close(%d) failed", fd);
failed = 1;
}
if (failed)
exit(1);
}
static void __attribute__((__noreturn__)) usage(int status)
{
FILE *out = status ? stderr : stdout;
fprintf(out,
"Usage: post-process-pe [OPTIONS] file0 [file1 [.. fileN]]\n");
fprintf(out, "Options:\n");
fprintf(out, " -q Be more quiet\n");
fprintf(out, " -v Be more verbose\n");
fprintf(out, " -N Disable the NX compatibility flag\n");
fprintf(out, " -n Enable the NX compatibility flag\n");
fprintf(out, " -h Print this help text and exit\n");
exit(status);
}
int main(int argc, char **argv)
{
int i;
struct option options[] = {
{.name = "help",
.val = '?',
},
{.name = "usage",
.val = '?',
},
{.name = "disable-nx-compat",
.val = 'N',
},
{.name = "enable-nx-compat",
.val = 'n',
},
{.name = "quiet",
.val = 'q',
},
{.name = "verbose",
.val = 'v',
},
{.name = ""}
};
int longindex = -1;
while ((i = getopt_long(argc, argv, "hNnqv", options, &longindex)) != -1) {
switch (i) {
case 'h':
case '?':
usage(longindex == -1 ? 1 : 0);
break;
case 'N':
set_nx_compat = false;
break;
case 'n':
set_nx_compat = true;
break;
case 'q':
verbosity = MAX(verbosity - 1, MIN_VERBOSITY);
break;
case 'v':
verbosity = MIN(verbosity + 1, MAX_VERBOSITY);
break;
}
}
if (optind == argc)
usage(1);
for (i = optind; i < argc; i++)
handle_one(argv[i]);
return 0;
}
// vim:fenc=utf-8:tw=75:noet