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| author | H.J. Lu <hjl.tools@gmail.com> | 2018-07-14 05:59:29 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2018-07-14 05:59:53 -0700 |
| commit | faaee1f07ed25b2779bfd935ffb29f431b80d6d3 (patch) | |
| tree | 3c85f88e2312c67e0f0e54be10b0bec833c7541f /sysdeps/unix/sysv/linux/i386 | |
| parent | ebff9c5cfae62e84dbd0456d564bd882818dc15f (diff) | |
| download | glibc-faaee1f07ed25b2779bfd935ffb29f431b80d6d3.tar.gz glibc-faaee1f07ed25b2779bfd935ffb29f431b80d6d3.tar.xz glibc-faaee1f07ed25b2779bfd935ffb29f431b80d6d3.zip | |
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/unix/sysv/linux/i386')
| -rw-r--r-- | sysdeps/unix/sysv/linux/i386/____longjmp_chk.S | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S index 3452433112..a7640d9892 100644 --- a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S +++ b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S @@ -17,9 +17,14 @@ #include <sysdep.h> #include <jmpbuf-offsets.h> +#include <jmp_buf-ssp.h> #include <asm-syntax.h> #include <stap-probe.h> +/* Don't restore shadow stack register if shadow stack isn't enabled. */ +#if !SHSTK_ENABLED +# undef SHADOW_STACK_POINTER_OFFSET +#endif .section .rodata.str1.1,"aMS",@progbits,1 .type longjmp_msg,@object @@ -46,6 +51,38 @@ longjmp_msg: ENTRY (____longjmp_chk) movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */ +#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, %gs:FEATURE_1_OFFSET + jz L(skip_ssp) +# else + xorl %edx, %edx +# endif + /* Check and adjust the Shadow-Stack-Pointer. */ + rdsspd %edx + /* And compare it with the saved ssp value. */ + subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx + je L(skip_ssp) + /* 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 + the number of frames is bigger than 255. */ + negl %edx + shrl $2, %edx + /* NB: We saved Shadow-Stack-Pointer of setjmp. Since we are + restoring Shadow-Stack-Pointer of setjmp's caller, we + need to unwind shadow stack by one more frame. */ + addl $1, %edx + movl $255, %ebx +L(loop): + cmpl %ebx, %edx + cmovb %edx, %ebx + incsspd %ebx + subl %ebx, %edx + ja L(loop) +L(skip_ssp): +#endif /* Save the return address now. */ movl (JB_PC*4)(%ecx), %edx /* Get the stack pointer. */ |