[PATCH v4 1/2] module: add elf_check_module_arch for module specific elf arch checks

Nicholas Piggin
2021-06-11T09:41:23Z

The elf_check_arch() function is used to test usermode binaries, but
kernel modules may have more specific requirements. powerpc would like
to test for ABI version compatibility.

Add an arch-overridable function elf_check_module_arch() that defaults
to elf_check_arch() and use it in elf_validity_check().

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[np: split patch, added changelog]
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
include/linux/moduleloader.h | 5 +++++
kernel/module.c | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/moduleloader.h b/include/linux/moduleloader.h
index 9e09d11ffe5b..fdc042a84562 100644
--- a/include/linux/moduleloader.h
+++ b/include/linux/moduleloader.h
@@ -13,6 +13,11 @@
* must be implemented by each architecture.
*/

+// Allow arch to optionally do additional checking of module ELF header
+#ifndef elf_check_module_arch
+#define elf_check_module_arch elf_check_arch
+#endif
+
/* Adjust arch-specific sections. Return 0 on success. */
int module_frob_arch_sections(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
diff --git a/kernel/module.c b/kernel/module.c
index 7e78dfabca97..7c3f9b7478dc 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2946,7 +2946,7 @@ static int elf_validity_check(struct load_info *info)

if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0
|| info->hdr->e_type != ET_REL
- || !elf_check_arch(info->hdr)
+ || !elf_check_module_arch(info->hdr)
|| info->hdr->e_shentsize != sizeof(Elf_Shdr))
return -ENOEXEC;

--
2.23.0