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link_elf_obj: Handle init_array sections in KLDs

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Reuse existing handling for .ctors, print a warning if multiple
constructor sections are present.   Destructors are not handled as of
yet.

This is required for KASAN.

Reviewed by:	kib
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D29049
This commit is contained in:
Mark Johnston 2021-03-04 10:02:47 -05:00
parent 23553d6b94
commit 5e6989ba4f
1 changed files with 36 additions and 7 deletions
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43
sys/kern/link_elf_obj.c
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@ -386,6 +386,8 @@ link_elf_link_preload(linker_class_t cls, const char *filename,
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
case SHT_INIT_ARRAY:
case SHT_FINI_ARRAY:
/* Ignore sections not loaded by the loader. */
if (shdr[i].sh_addr == 0)
break;
@ -470,6 +472,7 @@ link_elf_link_preload(linker_class_t cls, const char *filename,
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
case SHT_FINI_ARRAY:
if (shdr[i].sh_addr == 0)
break;
ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
@ -479,6 +482,10 @@ link_elf_link_preload(linker_class_t cls, const char *filename,
else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
ef->progtab[pb].name = "<<UNWIND>>";
#endif
else if (shdr[i].sh_type == SHT_INIT_ARRAY)
ef->progtab[pb].name = "<<INIT_ARRAY>>";
else if (shdr[i].sh_type == SHT_FINI_ARRAY)
ef->progtab[pb].name = "<<FINI_ARRAY>>";
else
ef->progtab[pb].name = "<<NOBITS>>";
ef->progtab[pb].size = shdr[i].sh_size;
@ -525,10 +532,17 @@ link_elf_link_preload(linker_class_t cls, const char *filename,
vnet_data_copy(vnet_data, shdr[i].sh_size);
ef->progtab[pb].addr = vnet_data;
#endif
} else if (ef->progtab[pb].name != NULL &&
!strcmp(ef->progtab[pb].name, ".ctors")) {
lf->ctors_addr = ef->progtab[pb].addr;
lf->ctors_size = shdr[i].sh_size;
} else if ((ef->progtab[pb].name != NULL &&
strcmp(ef->progtab[pb].name, ".ctors") == 0) ||
shdr[i].sh_type == SHT_INIT_ARRAY) {
if (lf->ctors_addr != 0) {
printf(
"%s: multiple ctor sections in %s\n",
__func__, filename);
} else {
lf->ctors_addr = ef->progtab[pb].addr;
lf->ctors_size = shdr[i].sh_size;
}
}
/* Update all symbol values with the offset. */
@ -773,6 +787,8 @@ link_elf_load_file(linker_class_t cls, const char *filename,
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
case SHT_INIT_ARRAY:
case SHT_FINI_ARRAY:
if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
break;
ef->nprogtab++;
@ -894,6 +910,8 @@ link_elf_load_file(linker_class_t cls, const char *filename,
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
case SHT_INIT_ARRAY:
case SHT_FINI_ARRAY:
if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
break;
alignmask = shdr[i].sh_addralign - 1;
@ -971,6 +989,8 @@ link_elf_load_file(linker_class_t cls, const char *filename,
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
case SHT_INIT_ARRAY:
case SHT_FINI_ARRAY:
if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
break;
alignmask = shdr[i].sh_addralign - 1;
@ -979,9 +999,18 @@ link_elf_load_file(linker_class_t cls, const char *filename,
if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
ef->progtab[pb].name =
ef->shstrtab + shdr[i].sh_name;
if (!strcmp(ef->progtab[pb].name, ".ctors")) {
lf->ctors_addr = (caddr_t)mapbase;
lf->ctors_size = shdr[i].sh_size;
if (!strcmp(ef->progtab[pb].name, ".ctors") ||
shdr[i].sh_type == SHT_INIT_ARRAY) {
if (lf->ctors_addr != 0) {
printf(
"%s: multiple ctor sections in %s\n",
__func__, filename);
} else {
lf->ctors_addr =
(caddr_t)mapbase;
lf->ctors_size =
shdr[i].sh_size;
}
}
} else if (shdr[i].sh_type == SHT_PROGBITS)
ef->progtab[pb].name = "<<PROGBITS>>";