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authorH.J. Lu <hjl.tools@gmail.com>2018-07-14 05:59:29 -0700
committerH.J. Lu <hjl.tools@gmail.com>2018-07-14 05:59:53 -0700
commitfaaee1f07ed25b2779bfd935ffb29f431b80d6d3 (patch)
tree3c85f88e2312c67e0f0e54be10b0bec833c7541f /sysdeps/x86_64/setjmp.S
parentebff9c5cfae62e84dbd0456d564bd882818dc15f (diff)
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x86: Support shadow stack pointer in setjmp/longjmp
Save and restore shadow stack pointer in setjmp and longjmp to support
shadow stack in Intel CET.  Use feature_1 in tcbhead_t to check if
shadow stack is enabled before saving and restoring shadow stack pointer.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

	* sysdeps/i386/__longjmp.S: Include <jmp_buf-ssp.h>.
	(__longjmp): Restore shadow stack pointer if shadow stack is
	enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
	isn't defined for __longjmp_cancel.
	* sysdeps/i386/bsd-_setjmp.S: Include <jmp_buf-ssp.h>.
	(_setjmp): Save shadow stack pointer if shadow stack is enabled
	and SHADOW_STACK_POINTER_OFFSET is defined.
	* sysdeps/i386/bsd-setjmp.S: Include <jmp_buf-ssp.h>.
	(setjmp): Save shadow stack pointer if shadow stack is enabled
	and SHADOW_STACK_POINTER_OFFSET is defined.
	* sysdeps/i386/setjmp.S: Include <jmp_buf-ssp.h>.
	(__sigsetjmp): Save shadow stack pointer if shadow stack is
	enabled and SHADOW_STACK_POINTER_OFFSET is defined.
	* sysdeps/unix/sysv/linux/i386/____longjmp_chk.S: Include
	<jmp_buf-ssp.h>.
	(____longjmp_chk): Restore shadow stack pointer if shadow stack
	is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
	* sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers):
	Remove jmp_buf-ssp.sym.
	* sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Include
	<jmp_buf-ssp.h>.
	(____longjmp_chk): Restore shadow stack pointer if shadow stack
	is enabled and SHADOW_STACK_POINTER_OFFSET is defined.
	* sysdeps/x86/Makefile (gen-as-const-headers): Add
	jmp_buf-ssp.sym.
	* sysdeps/x86/jmp_buf-ssp.sym: New dummy file.
	* sysdeps/x86_64/__longjmp.S: Include <jmp_buf-ssp.h>.
	(__longjmp): Restore shadow stack pointer if shadow stack is
	enabled, SHADOW_STACK_POINTER_OFFSET is defined and __longjmp
	isn't defined for __longjmp_cancel.
	* sysdeps/x86_64/setjmp.S: Include <jmp_buf-ssp.h>.
	(__sigsetjmp): Save shadow stack pointer if shadow stack is
	enabled and SHADOW_STACK_POINTER_OFFSET is defined.
Diffstat (limited to 'sysdeps/x86_64/setjmp.S')
-rw-r--r--sysdeps/x86_64/setjmp.S21
1 files changed, 21 insertions, 0 deletions
diff --git a/sysdeps/x86_64/setjmp.S b/sysdeps/x86_64/setjmp.S
index e0a648e3e4..78a8bf4644 100644
--- a/sysdeps/x86_64/setjmp.S
+++ b/sysdeps/x86_64/setjmp.S
@@ -18,9 +18,15 @@
 
 #include <sysdep.h>
 #include <jmpbuf-offsets.h>
+#include <jmp_buf-ssp.h>
 #include <asm-syntax.h>
 #include <stap-probe.h>
 
+/* Don't save shadow stack register if shadow stack isn't enabled.  */
+#if !SHSTK_ENABLED
+# undef SHADOW_STACK_POINTER_OFFSET
+#endif
+
 ENTRY (__sigsetjmp)
 	/* Save registers.  */
 	movq %rbx, (JB_RBX*8)(%rdi)
@@ -54,6 +60,21 @@ ENTRY (__sigsetjmp)
 #endif
 	movq %rax, (JB_PC*8)(%rdi)
 
+#ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+	/* Check if Shadow Stack is enabled.  */
+	testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET
+	jz L(skip_ssp)
+# else
+	xorl %eax, %eax
+# endif
+	/* Get the current Shadow-Stack-Pointer and save it.  */
+	rdsspq %rax
+	movq %rax, SHADOW_STACK_POINTER_OFFSET(%rdi)
+# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
+L(skip_ssp):
+# endif
+#endif
 #if IS_IN (rtld)
 	/* In ld.so we never save the signal mask.  */
 	xorl %eax, %eax