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-rw-r--r--tools/lib/bpf/linker.c233
1 files changed, 127 insertions, 106 deletions
diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c
index 4e08bc07e635..0bb927226370 100644
--- a/tools/lib/bpf/linker.c
+++ b/tools/lib/bpf/linker.c
@@ -131,6 +131,8 @@ static int init_output_elf(struct bpf_linker *linker, const char *file);
static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, struct src_obj *obj);
static int linker_sanity_check_elf(struct src_obj *obj);
+static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *sec);
+static int linker_sanity_check_elf_relos(struct src_obj *obj, struct src_sec *sec);
static int linker_sanity_check_btf(struct src_obj *obj);
static int linker_sanity_check_btf_ext(struct src_obj *obj);
static int linker_fixup_btf(struct src_obj *obj);
@@ -663,8 +665,8 @@ static bool is_pow_of_2(size_t x)
static int linker_sanity_check_elf(struct src_obj *obj)
{
- struct src_sec *sec, *link_sec;
- int i, j, n;
+ struct src_sec *sec;
+ int i, err;
if (!obj->symtab_sec_idx) {
pr_warn("ELF is missing SYMTAB section in %s\n", obj->filename);
@@ -692,43 +694,11 @@ static int linker_sanity_check_elf(struct src_obj *obj)
return -EINVAL;
switch (sec->shdr->sh_type) {
- case SHT_SYMTAB: {
- Elf64_Sym *sym;
-
- if (sec->shdr->sh_entsize != sizeof(Elf64_Sym))
- return -EINVAL;
- if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0)
- return -EINVAL;
-
- if (!sec->shdr->sh_link || sec->shdr->sh_link >= obj->sec_cnt) {
- pr_warn("ELF SYMTAB section #%zu points to missing STRTAB section #%zu in %s\n",
- sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename);
- return -EINVAL;
- }
- link_sec = &obj->secs[sec->shdr->sh_link];
- if (link_sec->shdr->sh_type != SHT_STRTAB) {
- pr_warn("ELF SYMTAB section #%zu points to invalid STRTAB section #%zu in %s\n",
- sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename);
- return -EINVAL;
- }
-
- n = sec->shdr->sh_size / sec->shdr->sh_entsize;
- sym = sec->data->d_buf;
- for (j = 0; j < n; j++, sym++) {
- if (sym->st_shndx
- && sym->st_shndx < SHN_LORESERVE
- && sym->st_shndx >= obj->sec_cnt) {
- pr_warn("ELF sym #%d in section #%zu points to missing section #%zu in %s\n",
- j, sec->sec_idx, (size_t)sym->st_shndx, obj->filename);
- return -EINVAL;
- }
- if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION) {
- if (sym->st_value != 0)
- return -EINVAL;
- }
- }
+ case SHT_SYMTAB:
+ err = linker_sanity_check_elf_symtab(obj, sec);
+ if (err)
+ return err;
break;
- }
case SHT_STRTAB:
break;
case SHT_PROGBITS:
@@ -739,87 +709,138 @@ static int linker_sanity_check_elf(struct src_obj *obj)
break;
case SHT_NOBITS:
break;
- case SHT_REL: {
- Elf64_Rel *relo;
- struct src_sec *sym_sec;
+ case SHT_REL:
+ err = linker_sanity_check_elf_relos(obj, sec);
+ if (err)
+ return err;
+ break;
+ case SHT_LLVM_ADDRSIG:
+ break;
+ default:
+ pr_warn("ELF section #%zu (%s) has unrecognized type %zu in %s\n",
+ sec->sec_idx, sec->sec_name, (size_t)sec->shdr->sh_type, obj->filename);
+ return -EINVAL;
+ }
+ }
- if (sec->shdr->sh_entsize != sizeof(Elf64_Rel))
- return -EINVAL;
- if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0)
- return -EINVAL;
+ return 0;
+}
- /* SHT_REL's sh_link should point to SYMTAB */
- if (sec->shdr->sh_link != obj->symtab_sec_idx) {
- pr_warn("ELF relo section #%zu points to invalid SYMTAB section #%zu in %s\n",
- sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename);
- return -EINVAL;
- }
+static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *sec)
+{
+ struct src_sec *link_sec;
+ Elf64_Sym *sym;
+ int i, n;
- /* SHT_REL's sh_info points to relocated section */
- if (!sec->shdr->sh_info || sec->shdr->sh_info >= obj->sec_cnt) {
- pr_warn("ELF relo section #%zu points to missing section #%zu in %s\n",
- sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename);
- return -EINVAL;
- }
- link_sec = &obj->secs[sec->shdr->sh_info];
+ if (sec->shdr->sh_entsize != sizeof(Elf64_Sym))
+ return -EINVAL;
+ if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0)
+ return -EINVAL;
+
+ if (!sec->shdr->sh_link || sec->shdr->sh_link >= obj->sec_cnt) {
+ pr_warn("ELF SYMTAB section #%zu points to missing STRTAB section #%zu in %s\n",
+ sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename);
+ return -EINVAL;
+ }
+ link_sec = &obj->secs[sec->shdr->sh_link];
+ if (link_sec->shdr->sh_type != SHT_STRTAB) {
+ pr_warn("ELF SYMTAB section #%zu points to invalid STRTAB section #%zu in %s\n",
+ sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename);
+ return -EINVAL;
+ }
- /* .rel<secname> -> <secname> pattern is followed */
- if (strncmp(sec->sec_name, ".rel", sizeof(".rel") - 1) != 0
- || strcmp(sec->sec_name + sizeof(".rel") - 1, link_sec->sec_name) != 0) {
- pr_warn("ELF relo section #%zu name has invalid name in %s\n",
- sec->sec_idx, obj->filename);
+ n = sec->shdr->sh_size / sec->shdr->sh_entsize;
+ sym = sec->data->d_buf;
+ for (i = 0; i < n; i++, sym++) {
+ if (sym->st_shndx
+ && sym->st_shndx < SHN_LORESERVE
+ && sym->st_shndx >= obj->sec_cnt) {
+ pr_warn("ELF sym #%d in section #%zu points to missing section #%zu in %s\n",
+ i, sec->sec_idx, (size_t)sym->st_shndx, obj->filename);
+ return -EINVAL;
+ }
+ if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION) {
+ if (sym->st_value != 0)
return -EINVAL;
- }
+ continue;
+ }
+ }
- /* don't further validate relocations for ignored sections */
- if (link_sec->skipped)
- break;
+ return 0;
+}
- /* relocatable section is data or instructions */
- if (link_sec->shdr->sh_type != SHT_PROGBITS
- && link_sec->shdr->sh_type != SHT_NOBITS) {
- pr_warn("ELF relo section #%zu points to invalid section #%zu in %s\n",
- sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename);
- return -EINVAL;
- }
+static int linker_sanity_check_elf_relos(struct src_obj *obj, struct src_sec *sec)
+{
+ struct src_sec *link_sec, *sym_sec;
+ Elf64_Rel *relo;
+ int i, n;
- /* check sanity of each relocation */
- n = sec->shdr->sh_size / sec->shdr->sh_entsize;
- relo = sec->data->d_buf;
- sym_sec = &obj->secs[obj->symtab_sec_idx];
- for (j = 0; j < n; j++, relo++) {
- size_t sym_idx = ELF64_R_SYM(relo->r_info);
- size_t sym_type = ELF64_R_TYPE(relo->r_info);
-
- if (sym_type != R_BPF_64_64 && sym_type != R_BPF_64_32) {
- pr_warn("ELF relo #%d in section #%zu has unexpected type %zu in %s\n",
- j, sec->sec_idx, sym_type, obj->filename);
- return -EINVAL;
- }
+ if (sec->shdr->sh_entsize != sizeof(Elf64_Rel))
+ return -EINVAL;
+ if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0)
+ return -EINVAL;
- if (!sym_idx || sym_idx * sizeof(Elf64_Sym) >= sym_sec->shdr->sh_size) {
- pr_warn("ELF relo #%d in section #%zu points to invalid symbol #%zu in %s\n",
- j, sec->sec_idx, sym_idx, obj->filename);
- return -EINVAL;
- }
+ /* SHT_REL's sh_link should point to SYMTAB */
+ if (sec->shdr->sh_link != obj->symtab_sec_idx) {
+ pr_warn("ELF relo section #%zu points to invalid SYMTAB section #%zu in %s\n",
+ sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename);
+ return -EINVAL;
+ }
- if (link_sec->shdr->sh_flags & SHF_EXECINSTR) {
- if (relo->r_offset % sizeof(struct bpf_insn) != 0) {
- pr_warn("ELF relo #%d in section #%zu points to missing symbol #%zu in %s\n",
- j, sec->sec_idx, sym_idx, obj->filename);
- return -EINVAL;
- }
- }
- }
- break;
+ /* SHT_REL's sh_info points to relocated section */
+ if (!sec->shdr->sh_info || sec->shdr->sh_info >= obj->sec_cnt) {
+ pr_warn("ELF relo section #%zu points to missing section #%zu in %s\n",
+ sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename);
+ return -EINVAL;
+ }
+ link_sec = &obj->secs[sec->shdr->sh_info];
+
+ /* .rel<secname> -> <secname> pattern is followed */
+ if (strncmp(sec->sec_name, ".rel", sizeof(".rel") - 1) != 0
+ || strcmp(sec->sec_name + sizeof(".rel") - 1, link_sec->sec_name) != 0) {
+ pr_warn("ELF relo section #%zu name has invalid name in %s\n",
+ sec->sec_idx, obj->filename);
+ return -EINVAL;
+ }
+
+ /* don't further validate relocations for ignored sections */
+ if (link_sec->skipped)
+ return 0;
+
+ /* relocatable section is data or instructions */
+ if (link_sec->shdr->sh_type != SHT_PROGBITS && link_sec->shdr->sh_type != SHT_NOBITS) {
+ pr_warn("ELF relo section #%zu points to invalid section #%zu in %s\n",
+ sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename);
+ return -EINVAL;
+ }
+
+ /* check sanity of each relocation */
+ n = sec->shdr->sh_size / sec->shdr->sh_entsize;
+ relo = sec->data->d_buf;
+ sym_sec = &obj->secs[obj->symtab_sec_idx];
+ for (i = 0; i < n; i++, relo++) {
+ size_t sym_idx = ELF64_R_SYM(relo->r_info);
+ size_t sym_type = ELF64_R_TYPE(relo->r_info);
+
+ if (sym_type != R_BPF_64_64 && sym_type != R_BPF_64_32) {
+ pr_warn("ELF relo #%d in section #%zu has unexpected type %zu in %s\n",
+ i, sec->sec_idx, sym_type, obj->filename);
+ return -EINVAL;
}
- case SHT_LLVM_ADDRSIG:
- break;
- default:
- pr_warn("ELF section #%zu (%s) has unrecognized type %zu in %s\n",
- sec->sec_idx, sec->sec_name, (size_t)sec->shdr->sh_type, obj->filename);
+
+ if (!sym_idx || sym_idx * sizeof(Elf64_Sym) >= sym_sec->shdr->sh_size) {
+ pr_warn("ELF relo #%d in section #%zu points to invalid symbol #%zu in %s\n",
+ i, sec->sec_idx, sym_idx, obj->filename);
return -EINVAL;
}
+
+ if (link_sec->shdr->sh_flags & SHF_EXECINSTR) {
+ if (relo->r_offset % sizeof(struct bpf_insn) != 0) {
+ pr_warn("ELF relo #%d in section #%zu points to missing symbol #%zu in %s\n",
+ i, sec->sec_idx, sym_idx, obj->filename);
+ return -EINVAL;
+ }
+ }
}
return 0;
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-01 07:36:30 +0300