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elf: More bug fixes

This commit is contained in:
mintsuki 2021-07-17 08:19:03 +02:00
parent 5fa8ef5d37
commit f5b0a4ee25
3 changed files with 34 additions and 23 deletions
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10
stage23/lib/blib.c
View File

@ -70,6 +70,16 @@ uint64_t sqrt(uint64_t a_nInput) {
return res;
}
size_t get_trailing_zeros(uint64_t val) {
for (size_t i = 0; i < 64; i++) {
if ((val & 1) != 0) {
return i;
}
val >>= 1;
}
return 64;
}
#if uefi == 1
bool efi_boot_services_exited = false;

1
stage23/lib/blib.h
View File

@ -33,6 +33,7 @@ extern bool verbose;
bool parse_resolution(int *width, int *height, int *bpp, const char *buf);
uint64_t sqrt(uint64_t a_nInput);
size_t get_trailing_zeros(uint64_t val);
int digit_to_int(char c);
uint8_t bcd_to_int(uint8_t val);

46
stage23/lib/elf.c
View File

@ -292,8 +292,8 @@ int elf32_load_section(uint8_t *elf, void *buffer, const char *name, size_t limi
return 2;
}
static uint64_t elf64_min_align(uint8_t *elf, bool use_paddr) {
uint64_t ret = 0xffffffffffffffff;
static uint64_t elf64_max_align(uint8_t *elf, bool use_paddr) {
uint64_t ret = 0;
struct elf64_hdr hdr;
memcpy(&hdr, elf + (0), sizeof(struct elf64_hdr));
@ -314,32 +314,27 @@ static uint64_t elf64_min_align(uint8_t *elf, bool use_paddr) {
load_addr = phdr.p_vaddr;
}
if (load_addr % 0x200000 == 0) {
if (ret > 0x200000) {
ret = 0x200000;
}
continue;
size_t trailing_zeros = get_trailing_zeros(load_addr);
uint64_t align = (uint64_t)1 << trailing_zeros;
if (align < 0x1000) {
// We don't do kernels that don't align their load addresses to 4K at least.
panic("elf: The executable contains non-4KiB aligned segments");
}
if (load_addr % 0x1000 == 0) {
if (ret > 0x1000) {
ret = 0x1000;
}
continue;
if (align > ret) {
ret = align;
}
// We don't do kernels that don't align their load addresses to 4K at least.
panic("elf: The executable contains non-4KiB aligned segments");
}
if (ret == 0xffffffffffffffff) {
if (ret == 0) {
panic("elf: Executable has no loadable segments");
}
return ret;
}
static void elf64_get_ranges(uint8_t *elf, uint64_t slide, uint64_t min_align, bool use_paddr, struct elf_range **_ranges, uint64_t *_ranges_count) {
static void elf64_get_ranges(uint8_t *elf, uint64_t slide, bool use_paddr, struct elf_range **_ranges, uint64_t *_ranges_count) {
struct elf64_hdr hdr;
memcpy(&hdr, elf + (0), sizeof(struct elf64_hdr));
@ -378,7 +373,7 @@ static void elf64_get_ranges(uint8_t *elf, uint64_t slide, uint64_t min_align, b
load_addr += slide;
ranges[r].base = load_addr;
ranges[r].length = ALIGN_UP(phdr.p_memsz, min_align);
ranges[r].length = ALIGN_UP(phdr.p_memsz, 4096);
ranges[r].permissions = phdr.p_flags & 0b111;
r++;
@ -415,9 +410,9 @@ int elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *top, uint64_t *_sl
uint64_t entry = hdr.entry;
bool entry_adjusted = false;
uint64_t min_align = 1;
uint64_t max_align = 1;
if (ranges != NULL) {
min_align = elf64_min_align(elf, use_paddr);
max_align = elf64_max_align(elf, use_paddr);
}
if (!elf64_is_relocatable(elf, &hdr)) {
@ -427,7 +422,7 @@ int elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *top, uint64_t *_sl
again:
if (kaslr)
slide = (rand64() & KASLR_SLIDE_BITMASK) & ~(min_align - 1);
slide = (rand64() & KASLR_SLIDE_BITMASK) & ~(max_align - 1);
final:
if (top)
@ -454,7 +449,12 @@ final:
load_addr += slide;
uint64_t load_size = ALIGN_UP(phdr.p_memsz, min_align);
uint64_t load_size;
if (ranges != NULL) {
load_size = ALIGN_UP(phdr.p_memsz, 4096);
} else {
load_size = phdr.p_memsz;
}
if (top) {
uint64_t this_top = load_addr + load_size;
@ -502,7 +502,7 @@ final:
*_slide = slide;
if (ranges_count != NULL && ranges != NULL) {
elf64_get_ranges(elf, slide, min_align, use_paddr, ranges, ranges_count);
elf64_get_ranges(elf, slide, use_paddr, ranges, ranges_count);
}
return 0;