git: 5e6989ba4f26 - main - link_elf_obj: Handle init_array sections in KLDs

[Mark Johnston]

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=5e6989ba4f26acafc77baa6055c0a9e7fe683514

commit 5e6989ba4f26acafc77baa6055c0a9e7fe683514
Author:     Mark Johnston <markj at FreeBSD.org>
AuthorDate: 2021-03-04 15:02:47 +0000
Commit:     Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-03-04 15:07:10 +0000

    link_elf_obj: Handle init_array sections in KLDs
    
    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
---
 sys/kern/link_elf_obj.c | 43 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 36 insertions(+), 7 deletions(-)

diff --git a/sys/kern/link_elf_obj.c b/sys/kern/link_elf_obj.c
index 6b5a6df0a56f..337588bd5c00 100644
--- a/sys/kern/link_elf_obj.c
+++ b/sys/kern/link_elf_obj.c
@@ -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>>";