Re: [PATCH v4 1/2] module: add elf_check_module_arch for module specific elf arch checks
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From: Jessica Yu <jeyu@kernel.org>
Date: 2021-06-14 12:06:57
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lkml
+++ Nicholas Piggin [11/06/21 19:39 +1000]:quoted hunk ↗ jump to hunk
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
Hi Nicholas,
Why not make elf_check_module_arch() consistent with the other
arch-specific functions? Please see module_frob_arch_sections(),
module_{init,exit}_section(), etc in moduleloader.h. That is, they are
all __weak functions that are overridable by arches. We can maybe make
elf_check_module_arch() a weak symbol, available for arches to
override if they want to perform additional elf checks. Then we don't
have to have this one-off #define.
Thanks,
Jessica
quoted hunk ↗ jump to hunk
+ /* 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