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elf: allow elf64_load to use paddrs instead of vaddrs

This commit is contained in:
Kacper Słomiński 2021-06-29 15:50:20 +02:00
parent 22587856fd
commit 9115bc7b50
4 changed files with 32 additions and 14 deletions
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40
stage23/lib/elf.c
View File

@ -292,7 +292,7 @@ int elf32_load_section(uint8_t *elf, void *buffer, const char *name, size_t limi
return 2;
}
int elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *_slide, uint32_t alloc_type, bool kaslr) {
int elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *_slide, uint32_t alloc_type, bool kaslr, bool use_paddr) {
struct elf64_hdr hdr;
memcpy(&hdr, elf + (0), sizeof(struct elf64_hdr));
@ -316,6 +316,9 @@ int elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *_slide, uint32_t a
size_t try_count = 0;
size_t max_simulated_tries = 250;
uint64_t entry = hdr.entry;
bool entry_adjusted = false;
if (!elf64_is_relocatable(elf, &hdr)) {
simulation = false;
goto final;
@ -334,14 +337,20 @@ final:
if (phdr.p_type != PT_LOAD)
continue;
uint64_t load_vaddr = phdr.p_vaddr;
uint64_t load_addr = 0;
if (load_vaddr & ((uint64_t)1 << 63))
load_vaddr -= FIXED_HIGHER_HALF_OFFSET_64;
if (use_paddr) {
load_addr = phdr.p_paddr;
} else {
load_addr = phdr.p_vaddr;
load_vaddr += slide;
if (load_addr & ((uint64_t)1 << 63))
load_addr -= FIXED_HIGHER_HALF_OFFSET_64;
}
if (!memmap_alloc_range((size_t)load_vaddr, (size_t)phdr.p_memsz, alloc_type, true, false, simulation, false)) {
load_addr += slide;
if (!memmap_alloc_range((size_t)load_addr, (size_t)phdr.p_memsz, alloc_type, true, false, simulation, false)) {
if (++try_count == max_simulated_tries || simulation == false)
return -1;
if (!kaslr)
@ -349,17 +358,25 @@ final:
goto again;
}
memcpy((void *)(uintptr_t)load_vaddr, elf + (phdr.p_offset), phdr.p_filesz);
memcpy((void *)(uintptr_t)load_addr, elf + (phdr.p_offset), phdr.p_filesz);
size_t to_zero = (size_t)(phdr.p_memsz - phdr.p_filesz);
if (to_zero) {
void *ptr = (void *)(uintptr_t)(load_vaddr + phdr.p_filesz);
void *ptr = (void *)(uintptr_t)(load_addr + phdr.p_filesz);
memset(ptr, 0, to_zero);
}
if (elf64_apply_relocations(elf, &hdr, (void *)(uintptr_t)load_vaddr, phdr.p_vaddr, phdr.p_memsz, slide))
if (elf64_apply_relocations(elf, &hdr, (void *)(uintptr_t)load_addr, phdr.p_vaddr, phdr.p_memsz, slide))
return -1;
if (use_paddr) {
if (!entry_adjusted && entry >= phdr.p_vaddr && entry <= (phdr.p_vaddr + phdr.p_memsz)) {
entry -= phdr.p_vaddr;
entry += phdr.p_paddr;
entry_adjusted = true;
}
}
}
if (simulation) {
@ -367,8 +384,9 @@ final:
goto final;
}
*entry_point = hdr.entry + slide;
*_slide = slide;
*entry_point = entry + slide;
if (_slide)
*_slide = slide;
return 0;
}

2
stage23/lib/elf.h
View File

@ -9,7 +9,7 @@
int elf_bits(uint8_t *elf);
int elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *slide, uint32_t alloc_type, bool kaslr);
int elf64_load(uint8_t *elf, uint64_t *entry_point, uint64_t *slide, uint32_t alloc_type, bool kaslr, bool use_paddr);
int elf64_load_section(uint8_t *elf, void *buffer, const char *name, size_t limit, uint64_t slide);
int elf32_load(uint8_t *elf, uint32_t *entry_point, uint32_t alloc_type);

2
stage23/protos/stivale.c
View File

@ -79,7 +79,7 @@ void stivale_load(char *config, char *cmdline) {
level5pg = true;
}
if (elf64_load(kernel, &entry_point, &slide, STIVALE_MMAP_KERNEL_AND_MODULES, kaslr))
if (elf64_load(kernel, &entry_point, &slide, STIVALE_MMAP_KERNEL_AND_MODULES, kaslr, false))
panic("stivale: ELF64 load failure");
ret = elf64_load_section(kernel, &stivale_hdr, ".stivalehdr", sizeof(struct stivale_header), slide);

2
stage23/protos/stivale2.c
View File

@ -101,7 +101,7 @@ void stivale2_load(char *config, char *cmdline, bool pxe, void *efi_system_table
level5pg = true;
}
if (elf64_load(kernel, &entry_point, &slide, STIVALE2_MMAP_KERNEL_AND_MODULES, kaslr))
if (elf64_load(kernel, &entry_point, &slide, STIVALE2_MMAP_KERNEL_AND_MODULES, kaslr, false))
panic("stivale2: ELF64 load failure");
ret = elf64_load_section(kernel, &stivale2_hdr, ".stivale2hdr", sizeof(struct stivale2_header), slide);