mirror of
https://github.com/limine-bootloader/limine
synced 2024-11-29 20:03:19 +03:00
lib/elf: Add RELR support
This commit is contained in:
mintsuki
parent
5a7052d135
commit
9789274c6d
362
common/lib/elf.c
362
common/lib/elf.c
@ -25,6 +25,9 @@
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#define DT_RELA 0x00000007
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#define DT_RELASZ 0x00000008
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#define DT_RELAENT 0x00000009
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#define DT_RELR 0x00000024
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#define DT_RELRSZ 0x00000023
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#define DT_RELRENT 0x00000025
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#define DT_SYMTAB 0x00000006
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#define DT_SYMENT 0x0000000b
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#define DT_PLTRELSZ 0x00000002
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@ -56,6 +59,8 @@
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#define R_RISCV_64 0x00000002
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#define R_AARCH64_ABS64 0x00000101
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#define R_INTERNAL_RELR 0xfffffff0
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/* Indices into identification array */
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#define EI_CLASS 4
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#define EI_DATA 5
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@ -248,6 +253,20 @@ static bool elf64_apply_relocations(uint8_t *elf, struct elf64_hdr *hdr, void *b
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panic(true, "elf: phdr_size < sizeof(struct elf64_phdr)");
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}
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uint64_t symtab_offset = 0;
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uint64_t symtab_ent = 0;
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uint64_t dt_pltrelsz = 0;
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uint64_t dt_jmprel = 0;
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uint64_t relr_offset = 0;
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uint64_t relr_size = 0;
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uint64_t relr_ent = 0;
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uint64_t rela_offset = 0;
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uint64_t rela_size = 0;
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uint64_t rela_ent = 0;
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// Find DYN segment
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for (uint16_t i = 0; i < hdr->ph_num; i++) {
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struct elf64_phdr *phdr = (void *)elf + (hdr->phoff + i * hdr->phdr_size);
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@ -255,15 +274,6 @@ static bool elf64_apply_relocations(uint8_t *elf, struct elf64_hdr *hdr, void *b
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if (phdr->p_type != PT_DYNAMIC)
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continue;
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uint64_t symtab_offset = 0;
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uint64_t symtab_ent = 0;
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uint64_t dt_pltrelsz = 0;
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uint64_t dt_jmprel = 0;
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uint64_t rela_offset = 0;
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uint64_t rela_size = 0;
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uint64_t rela_ent = 0;
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for (uint16_t j = 0; j < phdr->p_filesz / sizeof(struct elf64_dyn); j++) {
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struct elf64_dyn *dyn = (void *)elf + (phdr->p_offset + j * sizeof(struct elf64_dyn));
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@ -277,6 +287,15 @@ static bool elf64_apply_relocations(uint8_t *elf, struct elf64_hdr *hdr, void *b
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case DT_RELASZ:
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rela_size = dyn->d_un;
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break;
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case DT_RELR:
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relr_offset = dyn->d_un;
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break;
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case DT_RELRENT:
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relr_ent = dyn->d_un;
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break;
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case DT_RELRSZ:
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relr_size = dyn->d_un;
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break;
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case DT_SYMTAB:
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symtab_offset = dyn->d_un;
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break;
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@ -292,16 +311,16 @@ static bool elf64_apply_relocations(uint8_t *elf, struct elf64_hdr *hdr, void *b
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}
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}
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if (rela_offset == 0) {
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break;
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}
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break;
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}
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if (rela_offset != 0) {
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if (rela_ent < sizeof(struct elf64_rela)) {
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panic(true, "elf: sh_entsize < sizeof(struct elf64_rela)");
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panic(true, "elf: rela_ent < sizeof(struct elf64_rela)");
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}
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for (uint16_t j = 0; j < hdr->ph_num; j++) {
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struct elf64_phdr *_phdr = (void *)elf + (hdr->phoff + j * hdr->phdr_size);
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for (uint16_t i = 0; i < hdr->ph_num; i++) {
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struct elf64_phdr *_phdr = (void *)elf + (hdr->phoff + i * hdr->phdr_size);
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if (_phdr->p_vaddr <= rela_offset && _phdr->p_vaddr + _phdr->p_filesz > rela_offset) {
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rela_offset -= _phdr->p_vaddr;
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@ -309,133 +328,196 @@ static bool elf64_apply_relocations(uint8_t *elf, struct elf64_hdr *hdr, void *b
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break;
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}
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}
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if (symtab_ent < sizeof(struct elf64_sym)) {
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symtab_offset = 0;
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}
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if (symtab_offset != 0) {
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for (uint16_t j = 0; j < hdr->ph_num; j++) {
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struct elf64_phdr *_phdr = (void *)elf + (hdr->phoff + j * hdr->phdr_size);
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if (_phdr->p_vaddr <= symtab_offset && _phdr->p_vaddr + _phdr->p_filesz > symtab_offset) {
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symtab_offset -= _phdr->p_vaddr;
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symtab_offset += _phdr->p_offset;
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break;
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}
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}
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}
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if (dt_pltrelsz == 0) {
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dt_jmprel = 0;
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}
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if (dt_jmprel != 0) {
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for (uint16_t j = 0; j < hdr->ph_num; j++) {
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struct elf64_phdr *_phdr = (void *)elf + (hdr->phoff + j * hdr->phdr_size);
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if (_phdr->p_vaddr <= dt_jmprel && _phdr->p_vaddr + _phdr->p_filesz > dt_jmprel) {
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dt_jmprel -= _phdr->p_vaddr;
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dt_jmprel += _phdr->p_offset;
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break;
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}
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}
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}
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size_t relocs_i = rela_size / rela_ent;
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if (dt_jmprel != 0) {
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relocs_i += dt_pltrelsz / rela_ent;
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}
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struct elf64_rela **relocs = ext_mem_alloc(relocs_i * sizeof(struct elf64_rela *));
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for (uint64_t j = 0, offset = 0; offset < rela_size; offset += rela_ent) {
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relocs[j++] = (void *)elf + (rela_offset + offset);
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}
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if (dt_jmprel != 0) {
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for (uint64_t j = rela_size / rela_ent, offset = 0; offset < dt_pltrelsz; offset += rela_ent) {
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relocs[j++] = (void *)elf + (dt_jmprel + offset);
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}
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}
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for (size_t j = 0; j < relocs_i; j++) {
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struct elf64_rela *relocation = relocs[j];
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// Relocation is before buffer
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if (relocation->r_addr < vaddr)
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continue;
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// Relocation is after buffer
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if (vaddr + size < relocation->r_addr + 8)
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continue;
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// It's inside it, calculate where it is
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uint64_t *ptr = (uint64_t *)((buffer - vaddr) + relocation->r_addr);
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switch (relocation->r_info) {
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#if defined (__x86_64__) || defined (__i386__)
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case R_X86_64_NONE:
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#elif defined (__aarch64__)
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case R_AARCH64_NONE:
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#elif defined (__riscv64)
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case R_RISCV_NONE:
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#endif
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{
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break;
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}
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#if defined (__x86_64__) || defined (__i386__)
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case R_X86_64_RELATIVE:
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#elif defined (__aarch64__)
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case R_AARCH64_RELATIVE:
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#elif defined (__riscv64)
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case R_RISCV_RELATIVE:
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#endif
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{
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*ptr = slide + relocation->r_addend;
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break;
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}
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#if defined (__x86_64__) || defined (__i386__)
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case R_X86_64_GLOB_DAT:
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case R_X86_64_JUMP_SLOT:
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#elif defined (__aarch64__)
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case R_AARCH64_GLOB_DAT:
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case R_AARCH64_JUMP_SLOT:
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#elif defined (__riscv64)
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case R_RISCV_JUMP_SLOT:
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#endif
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{
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struct elf64_sym *s = (void *)elf + symtab_offset + symtab_ent * relocation->r_symbol;
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*ptr = slide + s->st_value
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#if defined (__aarch64__)
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+ relocation->r_addend
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#endif
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;
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break;
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}
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#if defined (__x86_64__) || defined (__i386__)
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case R_X86_64_64:
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#elif defined (__aarch64__)
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case R_AARCH64_ABS64:
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#elif defined (__riscv64)
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case R_RISCV_64:
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#endif
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{
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struct elf64_sym *s = (void *)elf + symtab_offset + symtab_ent * relocation->r_symbol;
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*ptr = slide + s->st_value + relocation->r_addend;
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break;
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}
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default: {
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print("elf: Unknown RELA type: %x\n", relocation->r_info);
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return false;
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}
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}
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}
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pmm_free(relocs, relocs_i * sizeof(struct elf64_rela *));
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break;
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}
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if (relr_offset != 0) {
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if (relr_ent != 8) {
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panic(true, "elf: relr_ent != 8");
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}
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for (uint16_t i = 0; i < hdr->ph_num; i++) {
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struct elf64_phdr *_phdr = (void *)elf + (hdr->phoff + i * hdr->phdr_size);
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if (_phdr->p_vaddr <= relr_offset && _phdr->p_vaddr + _phdr->p_filesz > relr_offset) {
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relr_offset -= _phdr->p_vaddr;
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relr_offset += _phdr->p_offset;
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break;
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}
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}
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}
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if (symtab_offset != 0) {
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if (symtab_ent < sizeof(struct elf64_sym)) {
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panic(true, "elf: symtab_ent < sizeof(struct elf64_sym)");
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}
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for (uint16_t i = 0; i < hdr->ph_num; i++) {
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struct elf64_phdr *_phdr = (void *)elf + (hdr->phoff + i * hdr->phdr_size);
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if (_phdr->p_vaddr <= symtab_offset && _phdr->p_vaddr + _phdr->p_filesz > symtab_offset) {
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symtab_offset -= _phdr->p_vaddr;
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symtab_offset += _phdr->p_offset;
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break;
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}
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}
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}
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if (dt_jmprel != 0) {
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if (rela_ent < sizeof(struct elf64_rela)) {
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panic(true, "elf: rela_ent < sizeof(struct elf64_rela)");
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}
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for (uint16_t i = 0; i < hdr->ph_num; i++) {
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struct elf64_phdr *_phdr = (void *)elf + (hdr->phoff + i * hdr->phdr_size);
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if (_phdr->p_vaddr <= dt_jmprel && _phdr->p_vaddr + _phdr->p_filesz > dt_jmprel) {
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dt_jmprel -= _phdr->p_vaddr;
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dt_jmprel += _phdr->p_offset;
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break;
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}
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}
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}
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size_t relocs_i = 0;
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if (relr_offset != 0) {
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for (size_t i = 0; i < relr_size / relr_ent; i++) {
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uint64_t entry = *((uint64_t *)(elf + relr_offset + i * relr_ent));
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if ((entry & 1) == 0) {
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relocs_i++;
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} else {
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relocs_i += __builtin_popcount(entry) - 1;
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}
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}
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}
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size_t relr_count = relocs_i;
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if (rela_offset != 0) {
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relocs_i += rela_size / rela_ent;
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}
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if (dt_jmprel != 0) {
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relocs_i += dt_pltrelsz / rela_ent;
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}
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struct elf64_rela **relocs = ext_mem_alloc(relocs_i * sizeof(struct elf64_rela *));
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if (relr_offset != 0) {
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size_t relr_i;
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for (relr_i = 0; relr_i < relr_count; relr_i++) {
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relocs[relr_i] = ext_mem_alloc(sizeof(struct elf64_rela));
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relocs[relr_i]->r_info = R_INTERNAL_RELR;
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}
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// This logic is partially lifted from https://maskray.me/blog/2021-10-31-relative-relocations-and-relr
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uint64_t where;
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relr_i = 0;
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for (size_t i = 0; i < relr_size / relr_ent; i++) {
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uint64_t entry = *((uint64_t *)(elf + relr_offset + i * relr_ent));
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if ((entry & 1) == 0) {
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where = entry;
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relocs[relr_i++]->r_addr = where;
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where += 8;
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} else {
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for (size_t j = 0; (entry >>= 1) != 0; j++) {
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if ((entry & 1) != 0) {
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relocs[relr_i++]->r_addr = where + j * 8;
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}
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}
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where += 63 * 8;
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}
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}
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}
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if (rela_offset != 0) {
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for (uint64_t i = relr_count, offset = 0; offset < rela_size; offset += rela_ent) {
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relocs[i++] = (void *)elf + (rela_offset + offset);
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}
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}
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if (dt_jmprel != 0) {
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for (uint64_t i = relr_count + rela_size / rela_ent, offset = 0; offset < dt_pltrelsz; offset += rela_ent) {
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relocs[i++] = (void *)elf + (dt_jmprel + offset);
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}
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}
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for (size_t i = 0; i < relocs_i; i++) {
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struct elf64_rela *relocation = relocs[i];
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// Relocation is before buffer
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if (relocation->r_addr < vaddr)
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continue;
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// Relocation is after buffer
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if (vaddr + size < relocation->r_addr + 8)
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continue;
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// It's inside it, calculate where it is
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uint64_t *ptr = (uint64_t *)((buffer - vaddr) + relocation->r_addr);
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switch (relocation->r_info) {
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#if defined (__x86_64__) || defined (__i386__)
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case R_X86_64_NONE:
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#elif defined (__aarch64__)
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case R_AARCH64_NONE:
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#elif defined (__riscv64)
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case R_RISCV_NONE:
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#endif
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{
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break;
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}
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#if defined (__x86_64__) || defined (__i386__)
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case R_X86_64_RELATIVE:
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#elif defined (__aarch64__)
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case R_AARCH64_RELATIVE:
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#elif defined (__riscv64)
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case R_RISCV_RELATIVE:
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#endif
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{
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*ptr = slide + relocation->r_addend;
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break;
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}
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case R_INTERNAL_RELR:
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{
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*ptr += slide;
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break;
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}
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#if defined (__x86_64__) || defined (__i386__)
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case R_X86_64_GLOB_DAT:
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case R_X86_64_JUMP_SLOT:
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#elif defined (__aarch64__)
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case R_AARCH64_GLOB_DAT:
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case R_AARCH64_JUMP_SLOT:
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#elif defined (__riscv64)
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case R_RISCV_JUMP_SLOT:
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#endif
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{
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struct elf64_sym *s = (void *)elf + symtab_offset + symtab_ent * relocation->r_symbol;
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*ptr = slide + s->st_value
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#if defined (__aarch64__)
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+ relocation->r_addend
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#endif
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;
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break;
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}
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#if defined (__x86_64__) || defined (__i386__)
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case R_X86_64_64:
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#elif defined (__aarch64__)
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case R_AARCH64_ABS64:
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#elif defined (__riscv64)
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case R_RISCV_64:
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#endif
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{
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struct elf64_sym *s = (void *)elf + symtab_offset + symtab_ent * relocation->r_symbol;
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*ptr = slide + s->st_value + relocation->r_addend;
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break;
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}
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default: {
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panic(true, "elf: Unknown relocation type: %x", relocation->r_info);
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}
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}
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}
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pmm_free(relocs, relocs_i * sizeof(struct elf64_rela *));
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return true;
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}
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