From 783e9350713f9c62e52834e738cd85bafe4622cc Mon Sep 17 00:00:00 2001 From: Jessica Yu Date: Tue, 1 Sep 2020 18:00:16 +0200 Subject: [PATCH 5/5] arm64/module: set trampoline section flags regardless of CONFIG_DYNAMIC_FTRACE In the arm64 module linker script, the section .text.ftrace_trampoline is specified unconditionally regardless of whether CONFIG_DYNAMIC_FTRACE is enabled (this is simply due to the limitation that module linker scripts are not preprocessed like the vmlinux one). Normally, for .plt and .text.ftrace_trampoline, the section flags present in the module binary wouldn't matter since module_frob_arch_sections() would assign them manually anyway. However, the arm64 module loader only sets the section flags for .text.ftrace_trampoline when CONFIG_DYNAMIC_FTRACE=y. That's only become problematic recently due to a recent change in binutils-2.35, where the .text.ftrace_trampoline section (along with the .plt section) is now marked writable and executable (WAX). We no longer allow writable and executable sections to be loaded due to commit 5c3a7db0c7ec ("module: Harden STRICT_MODULE_RWX"), so this is causing all modules linked with binutils-2.35 to be rejected under arm64. Drop the IS_ENABLED(CONFIG_DYNAMIC_FTRACE) check in module_frob_arch_sections() so that the section flags for .text.ftrace_trampoline get properly set to SHF_EXECINSTR|SHF_ALLOC, without SHF_WRITE. Link: http://lore.kernel.org/r/20200831094651.GA16385@linux-8ccs Acked-by: Will Deacon Signed-off-by: Jessica Yu Acked-by: Ard Biesheuvel --- arch/arm64/kernel/module-plts.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/arm64/kernel/module-plts.c b/arch/arm64/kernel/module-plts.c index 65b08a74aec6..37c0b51a7b7b 100644 --- a/arch/arm64/kernel/module-plts.c +++ b/arch/arm64/kernel/module-plts.c @@ -271,8 +271,7 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, mod->arch.core.plt_shndx = i; else if (!strcmp(secstrings + sechdrs[i].sh_name, ".init.plt")) mod->arch.init.plt_shndx = i; - else if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE) && - !strcmp(secstrings + sechdrs[i].sh_name, + else if (!strcmp(secstrings + sechdrs[i].sh_name, ".text.ftrace_trampoline")) tramp = sechdrs + i; else if (sechdrs[i].sh_type == SHT_SYMTAB) -- 2.27.0