diff options
Diffstat (limited to 'sysdeps/x86_64/__longjmp.S')
| -rw-r--r-- | sysdeps/x86_64/__longjmp.S | 47 |
1 files changed, 41 insertions, 6 deletions
diff --git a/sysdeps/x86_64/__longjmp.S b/sysdeps/x86_64/__longjmp.S index c9f70f8e2a..22fedc4997 100644 --- a/sysdeps/x86_64/__longjmp.S +++ b/sysdeps/x86_64/__longjmp.S @@ -22,14 +22,15 @@ #include <asm-syntax.h> #include <stap-probe.h> -/* Don't restore shadow stack register if - 1. Shadow stack isn't enabled. Or - 2. __longjmp is defined for __longjmp_cancel. - */ -#if !SHSTK_ENABLED || defined __longjmp +/* Don't restore shadow stack register if shadow stack isn't enabled. */ +#if !SHSTK_ENABLED || defined DO_NOT_RESTORE_SHADOW_STACK # undef SHADOW_STACK_POINTER_OFFSET #endif +#ifndef CHECK_INVALID_LONGJMP +# define CHECK_INVALID_LONGJMP +#endif + /* Jump to the position specified by ENV, causing the setjmp call there to return VAL, or 1 if VAL is 0. void __longjmp (__jmp_buf env, int val). */ @@ -52,6 +53,9 @@ ENTRY(__longjmp) orq %rax, %r9 # endif #endif + + CHECK_INVALID_LONGJMP + #ifdef SHADOW_STACK_POINTER_OFFSET # if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET /* Check if Shadow Stack is enabled. */ @@ -63,9 +67,40 @@ ENTRY(__longjmp) /* Check and adjust the Shadow-Stack-Pointer. */ /* Get the current ssp. */ rdsspq %rax + /* Save the current ssp. */ + movq %rax, %r10 /* And compare it with the saved ssp value. */ - subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax + movq SHADOW_STACK_POINTER_OFFSET(%rdi), %rcx + subq %rcx, %rax je L(skip_ssp) + + /* Save the target ssp. */ + movq %rcx, %r11 + +L(find_restore_token_loop): + /* Look for a restore token. */ + movq -8(%rcx), %rbx + andq $-8, %rbx + cmpq %rcx, %rbx + /* Find the restore token. */ + je L(restore_shadow_stack) + + /* Try the next slot. */ + subq $8, %rcx + /* Stop if the current ssp is found. */ + cmpq %rcx, %r10 + jne L(find_restore_token_loop) + jmp L(no_shadow_stack_token) + +L(restore_shadow_stack): + /* Restore the target shadow stack. */ + rstorssp -8(%rcx) + /* Save the restore token on the old shadow stack. */ + saveprevssp + rdsspq %rax + subq %r11, %rax + +L(no_shadow_stack_token): /* Count the number of frames to adjust and adjust it with incssp instruction. The instruction can adjust the ssp by [0..255] value only thus use a loop if |