Commit a5131c3f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'x86-shstk-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 shadow stacks from Ingo Molnar:
 "Enable shadow stacks for x32.

  While we normally don't do such feature-enabling for 32-bit anymore,
  this change is small, straightforward & tested on upstream glibc"

* tag 'x86-shstk-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/shstk: Enable shadow stacks for x32
parents 5f487cd8 2883f01e

arch/x86/entry/syscalls/syscall_64.tbl

+1 −1
Original line number Diff line number Diff line
@@ -374,7 +374,7 @@ 
450	common	set_mempolicy_home_node	sys_set_mempolicy_home_node

451	common	cachestat		sys_cachestat

452	common	fchmodat2		sys_fchmodat2

453	64	map_shadow_stack	sys_map_shadow_stack

453	common	map_shadow_stack	sys_map_shadow_stack

454	common	futex_wake		sys_futex_wake

455	common	futex_wait		sys_futex_wait

456	common	futex_requeue		sys_futex_requeue

arch/x86/kernel/shstk.c

+2 −2
Original line number Diff line number Diff line
@@ -163,8 +163,8 @@ static int shstk_setup(void) 
	if (features_enabled(ARCH_SHSTK_SHSTK))

		return 0;



	/* Also not supported for 32 bit and x32 */

	if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) || in_32bit_syscall())

	/* Also not supported for 32 bit */

	if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) || in_ia32_syscall())

		return -EOPNOTSUPP;



	size = adjust_shstk_size(0);

arch/x86/kernel/signal_64.c

+6 −0
Original line number Diff line number Diff line
@@ -315,6 +315,9 @@ int x32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 


	uc_flags = frame_uc_flags(regs);



	if (setup_signal_shadow_stack(ksig))

		return -EFAULT;



	if (!user_access_begin(frame, sizeof(*frame)))

		return -EFAULT;
@@ -377,6 +380,9 @@ COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn) 
	if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))

		goto badframe;



	if (restore_signal_shadow_stack())

		goto badframe;



	if (compat_restore_altstack(&frame->uc.uc_stack))

		goto badframe;