Bring SROP mitigation to arm64. Make some small modifications to the arm

code as well to improve diffability.  Changes the types used in the arm64
"struct sigcontext" to avoid having to include <sys/types.h>.

ok deraadt@

1 files changed, 8 insertions, 18 deletions

diff --git a/sys/arch/arm/arm/sig_machdep.c b/sys/arch/arm/arm/sig_machdep.c
index 43744c3c1ce..a0655e1bab1 100644
--- a/sys/arch/arm/arm/sig_machdep.c
+++ b/sys/arch/arm/arm/sig_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sig_machdep.c,v 1.14 2016/05/21 00:56:43 deraadt Exp $	*/
+/*	$OpenBSD: sig_machdep.c,v 1.15 2017/03/12 17:57:12 kettenis Exp $	*/
 /*	$NetBSD: sig_machdep.c,v 1.22 2003/10/08 00:28:41 thorpej Exp $	*/
 
 /*
@@ -61,7 +61,6 @@
 static __inline struct trapframe *
 process_frame(struct proc *p)
 {
-
 	return p->p_addr->u_pcb.pcb_tf;
 }
 
@@ -85,8 +84,6 @@ sendsig(sig_t catcher, int sig, int returnmask, u_long code, int type,
 
 	tf = process_frame(p);
 
-	/* Do we need to jump onto the signal stack? */
-
 	/* Allocate space for the signal handler context. */
 	if ((p->p_sigstk.ss_flags & SS_DISABLE) == 0 &&
 	    !sigonstack(tf->tf_usr_sp) && (psp->ps_sigonstack & sigmask(sig)))
@@ -99,7 +96,7 @@ sendsig(sig_t catcher, int sig, int returnmask, u_long code, int type,
 	fp--;
 
 	/* make the stack aligned */
-	fp = (void *)STACKALIGN(fp);
+	fp = (struct sigframe *)STACKALIGN(fp);
 
 	/* Build stack frame for signal trampoline. */
 	bzero(&frame, sizeof(frame));
@@ -148,22 +145,15 @@ sendsig(sig_t catcher, int sig, int returnmask, u_long code, int type,
 
 	/*
 	 * Build context to run handler in.  We invoke the handler
-	 * directly, only returning via the trampoline.  Note the
-	 * trampoline version numbers are coordinated with machine-
-	 * dependent code in libc.
-	 */
-
-	/*
-	 * this was all in the switch below, seemed daft to duplicate it, if
-	 * we do a new trampoline version it might change then
+	 * directly, only returning via the trampoline.
 	 */
 	tf->tf_r0 = sig;
-	tf->tf_r1 = (int)frame.sf_sip;
-	tf->tf_r2 = (int)frame.sf_scp;
-	tf->tf_pc = (int)frame.sf_handler;
-	tf->tf_usr_sp = (int)fp;
+	tf->tf_r1 = (register_t)frame.sf_sip;
+	tf->tf_r2 = (register_t)frame.sf_scp;
+	tf->tf_pc = (register_t)frame.sf_handler;
+	tf->tf_usr_sp = (register_t)fp;
 	
-	tf->tf_usr_lr = (int)p->p_p->ps_sigcode;
+	tf->tf_usr_lr = p->p_p->ps_sigcode;
 }
 
 /*