x86: Reject x32 executables if x32 ABI not supported
commit 0e6d3112a4e95d55cf6dca88f298d5f4b8f29bd1 upstream.
It is currently possible to execve() an x32 executable on an x86_64
kernel that has only ia32 compat enabled. However all its syscalls
will fail, even _exit(). This usually causes it to segfault.
Change the ELF compat architecture check so that x32 executables are
rejected if we don't support the x32 ABI.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Link: http://lkml.kernel.org/r/1410120305.6822.9.camel@decadent.org.uk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Zefan Li <lizefan@huawei.com>
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 5939f44..06ec1fe 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -155,8 +155,9 @@
#define elf_check_arch(x) \
((x)->e_machine == EM_X86_64)
-#define compat_elf_check_arch(x) \
- (elf_check_arch_ia32(x) || (x)->e_machine == EM_X86_64)
+#define compat_elf_check_arch(x) \
+ (elf_check_arch_ia32(x) || \
+ (IS_ENABLED(CONFIG_X86_X32_ABI) && (x)->e_machine == EM_X86_64))
#if __USER32_DS != __USER_DS
# error "The following code assumes __USER32_DS == __USER_DS"