From 3051f3495cad507afebe2f654d32b51629554e3e Mon Sep 17 00:00:00 2001 From: Sachin Monga Date: Wed, 20 Nov 2024 16:50:00 -0500 Subject: [PATCH] =?UTF-8?q?=EF=BB=BFpowerpc64le:=20=5Finit/=5Ffini=20file?= =?UTF-8?q?=20changes=20for=20ROP?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The ROP instructions were added in ISA 3.1 (ie, Power10), however they were defined so that if executed on older cpus, they would behave as nops. This allows us to emit them on older cpus and they'd just be ignored, but if run on a Power10, then the binary would be ROP protected. Hash instructions use negative offsets so the default position of ROP pointer is FRAME_ROP_SAVE from caller's SP. Modified FRAME_MIN_SIZE_PARM to 112 for ELFv2 to reserve additional 16 bytes for ROP save slot and padding. Signed-off-by: Sachin Monga Reviewed-by: Peter Bergner --- sysdeps/powerpc/powerpc64/crti.S | 6 ++++++ sysdeps/powerpc/powerpc64/crtn.S | 6 ++++++ sysdeps/powerpc/powerpc64/sysdep.h | 3 ++- 3 files changed, 14 insertions(+), 1 deletion(-) diff --git a/sysdeps/powerpc/powerpc64/crti.S b/sysdeps/powerpc/powerpc64/crti.S index 71bdddfb3b..e977bc4b9c 100644 --- a/sysdeps/powerpc/powerpc64/crti.S +++ b/sysdeps/powerpc/powerpc64/crti.S @@ -68,6 +68,9 @@ BODY_LABEL (_init): LOCALENTRY(_init) mflr 0 std 0, FRAME_LR_SAVE(r1) +#ifdef __ROP_PROTECT__ + hashst 0, FRAME_ROP_SAVE(r1) +#endif stdu r1, -FRAME_MIN_SIZE_PARM(r1) #if PREINIT_FUNCTION_WEAK addis r9, r2, .LC0@toc@ha @@ -87,4 +90,7 @@ BODY_LABEL (_fini): LOCALENTRY(_fini) mflr 0 std 0, FRAME_LR_SAVE(r1) +#ifdef __ROP_PROTECT__ + hashst 0, FRAME_ROP_SAVE(r1) +#endif stdu r1, -FRAME_MIN_SIZE_PARM(r1) diff --git a/sysdeps/powerpc/powerpc64/crtn.S b/sysdeps/powerpc/powerpc64/crtn.S index 4e91231f2c..a37e159950 100644 --- a/sysdeps/powerpc/powerpc64/crtn.S +++ b/sysdeps/powerpc/powerpc64/crtn.S @@ -42,10 +42,16 @@ addi r1, r1, FRAME_MIN_SIZE_PARM ld r0, FRAME_LR_SAVE(r1) mtlr r0 +#ifdef __ROP_PROTECT__ + hashchk 0, FRAME_ROP_SAVE(r1) +#endif blr .section .fini,"ax",@progbits addi r1, r1, FRAME_MIN_SIZE_PARM ld r0, FRAME_LR_SAVE(r1) mtlr r0 +#ifdef __ROP_PROTECT__ + hashchk 0, FRAME_ROP_SAVE(r1) +#endif blr diff --git a/sysdeps/powerpc/powerpc64/sysdep.h b/sysdeps/powerpc/powerpc64/sysdep.h index c439b06121..b5c70e526e 100644 --- a/sysdeps/powerpc/powerpc64/sysdep.h +++ b/sysdeps/powerpc/powerpc64/sysdep.h @@ -31,8 +31,9 @@ #define FRAME_TOC_SAVE 40 #define FRAME_PARM_SAVE 48 #else +#define FRAME_ROP_SAVE -8 #define FRAME_MIN_SIZE 32 -#define FRAME_MIN_SIZE_PARM 96 +#define FRAME_MIN_SIZE_PARM 112 /* Includes space for the ROP save slot */ #define FRAME_TOC_SAVE 24 #define FRAME_PARM_SAVE 32 #endif