mirrors/limine
1
0
Fork 0
mirror of https://github.com/limine-bootloader/limine synced 2024-11-23 00:51:54 +03:00
Code Issues Packages Projects Releases Wiki Activity

lib/elf: Apply a slide of 0xffffffff80000000 - min_vaddr instead of always 0xffffffff80000000 for relocatable kernels loaded low

Browse Source
This commit is contained in:
mintsuki 2024-07-06 18:44:54 +02:00
parent 329d989b01
commit 2c09275aab
3 changed files with 13 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
common/lib/elf.c
View File

@ -627,7 +627,7 @@ static void elf64_get_ranges(uint8_t *elf, uint64_t slide, struct elf_range **_r
}
if (phdr->p_vaddr < FIXED_HIGHER_HALF_OFFSET_64) {
if (!is_reloc || phdr->p_vaddr >= 0x80000000) {
if (!is_reloc) {
continue;
}
}
@ -650,7 +650,7 @@ static void elf64_get_ranges(uint8_t *elf, uint64_t slide, struct elf_range **_r
}
if (phdr->p_vaddr < FIXED_HIGHER_HALF_OFFSET_64) {
if (!is_reloc || phdr->p_vaddr >= 0x80000000) {
if (!is_reloc) {
continue;
}
}
@ -713,14 +713,13 @@ bool elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *_slide, uint32_t
}
if (phdr->p_vaddr < FIXED_HIGHER_HALF_OFFSET_64) {
if (!*is_reloc || phdr->p_vaddr >= 0x80000000) {
continue;
if (!*is_reloc) {
panic(true, "elf: Lower half PHDRs are not allowed");
}
lower_to_higher = true;
slide = FIXED_HIGHER_HALF_OFFSET_64;
} else {
if (lower_to_higher) {
panic(true, "elf: Mix of lower and higher half PHDRs");
panic(true, "elf: Mix of lower and higher half PHDRs in relocatable kernel");
}
}
@ -733,7 +732,7 @@ bool elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *_slide, uint32_t
}
if (phdr_in->p_vaddr < FIXED_HIGHER_HALF_OFFSET_64) {
if (!*is_reloc || phdr->p_vaddr >= 0x80000000) {
if (!*is_reloc) {
continue;
}
}
@ -781,6 +780,10 @@ bool elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *_slide, uint32_t
panic(true, "elf: No usable PHDRs exist");
}
if (lower_to_higher) {
slide = FIXED_HIGHER_HALF_OFFSET_64 - min_vaddr;
}
image_size = max_vaddr - min_vaddr;
*physical_base = (uintptr_t)ext_mem_alloc_type_aligned(image_size, alloc_type, max_align);
@ -792,7 +795,7 @@ bool elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *_slide, uint32_t
again:
if (*is_reloc && kaslr) {
slide = (rand32() & ~(max_align - 1)) + (lower_to_higher ? FIXED_HIGHER_HALF_OFFSET_64 : 0);
slide = (rand32() & ~(max_align - 1)) + (lower_to_higher ? FIXED_HIGHER_HALF_OFFSET_64 - min_vaddr : 0);
if (*virtual_base + slide + image_size < 0xffffffff80000000 /* this comparison relies on overflow */) {
if (++try_count == max_simulated_tries) {
@ -811,12 +814,6 @@ again:
continue;
}
if (phdr->p_vaddr < FIXED_HIGHER_HALF_OFFSET_64) {
if (!*is_reloc || phdr->p_vaddr >= 0x80000000) {
continue;
}
}
// Sanity checks
if (phdr->p_filesz > phdr->p_memsz) {
panic(true, "elf: p_filesz > p_memsz");

1
test/limine.c
View File

@ -252,6 +252,7 @@ static void limine_main(void) {
uint64_t kernel_slide = (uint64_t)kernel_start - 0xffffffff80000000;
e9_printf("Kernel start: %x", kernel_start);
e9_printf("Kernel slide: %x", kernel_slide);
FEAT_START

2
test/linker.ld
View File

@ -1,7 +1,7 @@
SECTIONS
{
. = SIZEOF_HEADERS;
kernel_start = .;
kernel_start = . - SIZEOF_HEADERS;
.rodata ALIGN(CONSTANT(MAXPAGESIZE)) : {
*(.rodata .rodata.*)