From: Jessica Yu <jeyu@xxxxxxxxxx>
[ Upstream commit e0328feda79d9681b3e3245e6e180295550c8ee9 ]
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.
Signed-off-by: Jessica Yu <jeyu@xxxxxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Link: http://lore.kernel.org/r/20200831094651.GA16385@linux-8ccs
Link: https://lore.kernel.org/r/20200901160016.3646-1-jeyu@xxxxxxxxxx
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 65b08a74aec65..37c0b51a7b7b5 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)
--
2.25.1
