From: deraadt <deraadt@openbsd.org>
Date: Tue, 12 Dec 2023 07:37:20 +0000 (+0000)
Subject: The sigtramp was calling sigreturn(2), and upon failure exit(2), which
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=d8417bd7da1c4c9f6786edfd187f5ed8fdaf04fb;p=openbsd

The sigtramp was calling sigreturn(2), and upon failure exit(2), which
doesn't make sense anymore.  It is better to just issue an illegal
instruction.
ok kettenis, with some misgivings about inconsistant approaches between
architectures.
In the future we could change sigreturn(2) to never return an exit code,
but always just terminate the process.  We stopped this system call
from being callable ages ago with msyscall(2), and there is no stub for
it in libc.. maybe that's the next step to take?
---

diff --git a/sys/arch/amd64/amd64/locore.S b/sys/arch/amd64/amd64/locore.S
index a3d496e44e1..b36ab19d853 100644
--- a/sys/arch/amd64/amd64/locore.S
+++ b/sys/arch/amd64/amd64/locore.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.S,v 1.142 2023/12/10 16:56:01 deraadt Exp $	*/
+/*	$OpenBSD: locore.S,v 1.143 2023/12/12 07:37:20 deraadt Exp $	*/
 /*	$NetBSD: locore.S,v 1.13 2004/03/25 18:33:17 drochner Exp $	*/
 
 /*
@@ -181,13 +181,10 @@ sigcodecall:
 	syscall
 	.globl	sigcoderet
 sigcoderet:
-	movq	$SYS_exit,%rax
-	syscall
-	_ALIGN_TRAPS
+	int3
 1:	JMP_RETPOLINE(rax)
 	.globl	esigcode
 esigcode:
-
 	.globl	sigfill
 sigfill:
 	int3
diff --git a/sys/arch/arm/arm/sigcode.S b/sys/arch/arm/arm/sigcode.S
index 70c0f54750e..b2402d8c1a1 100644
--- a/sys/arch/arm/arm/sigcode.S
+++ b/sys/arch/arm/arm/sigcode.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sigcode.S,v 1.13 2023/12/10 16:56:01 deraadt Exp $	*/
+/*	$OpenBSD: sigcode.S,v 1.14 2023/12/12 07:37:20 deraadt Exp $	*/
 /*	$NetBSD: sigcode.S,v 1.6 2003/10/05 19:44:58 matt Exp $	*/
 
 /*
@@ -63,14 +63,9 @@ sigcodecall:
 	isb
 	.globl  sigcoderet
 sigcoderet:
-	/* Well if that failed we better exit quick ! */
-	mov	r12, #SYS_exit
-	swi	0
-	dsb	nsh
-	isb
 	.global esigcode
 esigcode:
-
+	/* FALLTHROUGH */
 	.globl	sigfill
 sigfill:
 	udf	#0
diff --git a/sys/arch/arm64/arm64/locore.S b/sys/arch/arm64/arm64/locore.S
index 9f2faa0d213..771e7eff786 100644
--- a/sys/arch/arm64/arm64/locore.S
+++ b/sys/arch/arm64/arm64/locore.S
@@ -1,4 +1,4 @@
-/* $OpenBSD: locore.S,v 1.44 2023/12/10 16:56:01 deraadt Exp $ */
+/* $OpenBSD: locore.S,v 1.45 2023/12/12 07:37:20 deraadt Exp $ */
 /*-
  * Copyright (c) 2012-2014 Andrew Turner
  * All rights reserved.
@@ -372,16 +372,10 @@ sigcodecall:
 	isb
 	.globl  sigcoderet
 sigcoderet:
-
-	/* sigreturn failed, exit */
-	mov	x8, #SYS_exit
-	svc	0
-	dsb	nsh
-	isb
 END(sigcode)
 	.global esigcode
 esigcode:
-
+	/* FALLTHROUGH */
 	.globl	sigfill
 sigfill:
 	udf	#0
diff --git a/sys/arch/hppa/hppa/locore.S b/sys/arch/hppa/hppa/locore.S
index 28647e5f426..3c952c8bf1d 100644
--- a/sys/arch/hppa/hppa/locore.S
+++ b/sys/arch/hppa/hppa/locore.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.S,v 1.206 2023/12/10 16:56:01 deraadt Exp $	*/
+/*	$OpenBSD: locore.S,v 1.207 2023/12/12 07:37:20 deraadt Exp $	*/
 
 /*
  * Copyright (c) 1998-2004 Michael Shalayeff
@@ -2872,15 +2872,10 @@ sigcodecall:
 	 ldi	SYS_sigreturn, t1
 	.globl  sigcoderet
 sigcoderet:
-
-	ldil	L%SYSCALLGATE, r1
-	copy	ret0, arg0
-	.call
-	ble	4(sr7, r1)
-	ldi	SYS_exit, t1
+	break	0,0
 ALTENTRY(esigcode)
-EXIT(sigcode)
 
+EXIT(sigcode)
 	.globl	sigfill
 sigfill:
 	break	0,0
diff --git a/sys/arch/i386/i386/locore.s b/sys/arch/i386/i386/locore.s
index c3a749702a3..b25acfaab5c 100644
--- a/sys/arch/i386/i386/locore.s
+++ b/sys/arch/i386/i386/locore.s
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.s,v 1.203 2023/12/10 16:56:01 deraadt Exp $	*/
+/*	$OpenBSD: locore.s,v 1.204 2023/12/12 07:37:20 deraadt Exp $	*/
 /*	$NetBSD: locore.s,v 1.145 1996/05/03 19:41:19 christos Exp $	*/
 
 /*-
@@ -346,11 +346,9 @@ sigcodecall:
 	int	$0x80			# enter kernel with args on stack
 	.globl	sigcoderet
 sigcoderet:
-	movl	$SYS_exit,%eax
-	int	$0x80			# exit if sigreturn fails
 	.globl	esigcode
 esigcode:
-
+	/* FALLTHROUGH */
 	.globl	sigfill
 sigfill:
 	int3
diff --git a/sys/arch/m88k/m88k/subr.S b/sys/arch/m88k/m88k/subr.S
index 69d79fe859d..ff73eec1553 100644
--- a/sys/arch/m88k/m88k/subr.S
+++ b/sys/arch/m88k/m88k/subr.S
@@ -1,4 +1,4 @@
-/* $OpenBSD: subr.S,v 1.30 2023/12/10 16:56:01 deraadt Exp $	*/
+/* $OpenBSD: subr.S,v 1.31 2023/12/12 07:37:21 deraadt Exp $	*/
 /*
  * Mach Operating System
  * Copyright (c) 1993-1992 Carnegie Mellon University
@@ -1138,16 +1138,8 @@ GLOBAL(sigcoderet)
 #ifdef dontbother		/* sigreturn will not return unless it fails */
 	NOP			| success return
 #endif
-	or	%r13, %r0,  SYS_exit
-	tb0	0,    %r0,  450	/* syscall trap, exit */
-	/*
-	 * this never returns, but we need to provide fetchable instructions
-	 * for the 88100 pipeline.
-	 */
-	NOP
-	NOP
 GLOBAL(esigcode)
-
+	/* FALLTHROUGH */
 GLOBAL(sigfill)
 	tb0	0, %r0, 130	/* breakpoint */
 GLOBAL(sigfillsiz)
diff --git a/sys/arch/macppc/macppc/locore.S b/sys/arch/macppc/macppc/locore.S
index 76ed02fcee5..d1c59bf5979 100644
--- a/sys/arch/macppc/macppc/locore.S
+++ b/sys/arch/macppc/macppc/locore.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.S,v 1.63 2023/12/10 16:56:01 deraadt Exp $	*/
+/*	$OpenBSD: locore.S,v 1.64 2023/12/12 07:37:21 deraadt Exp $	*/
 /*	$NetBSD: locore.S,v 1.2 1996/10/16 19:33:09 ws Exp $	*/
 
 /*
@@ -1180,10 +1180,8 @@ sigcodecall:
 	sc				/* sigreturn(scp) */
 	.globl	sigcoderet
 sigcoderet:
-	li	%r0,SYS_exit
-	sc				/* exit(errno) */
 esigcode:
-
+	/* FALLTHROUGH */
 	.globl	sigfill
 sigfill:
 	.long	0		# illegal
diff --git a/sys/arch/mips64/mips64/lcore_access.S b/sys/arch/mips64/mips64/lcore_access.S
index f2106d14ef3..1aeb6c26fa8 100644
--- a/sys/arch/mips64/mips64/lcore_access.S
+++ b/sys/arch/mips64/mips64/lcore_access.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: lcore_access.S,v 1.35 2023/12/10 16:56:01 deraadt Exp $ */
+/*	$OpenBSD: lcore_access.S,v 1.36 2023/12/12 07:37:21 deraadt Exp $ */
 
 /*
  * Copyright (c) 2001-2003 Opsycon AB  (www.opsycon.se / www.opsycon.com)
@@ -80,11 +80,9 @@ sigcodecall:
 	syscall
 	.globl	sigcoderet
 sigcoderet:
-	LI	v0, SYS_exit		# just in case sigreturn fails
-	syscall
 	.globl	esigcode
 esigcode:
-
+	/* FALLTHROUGH */
 	.globl	sigfill
 sigfill:
 	teq	zero, zero, 0x52
diff --git a/sys/arch/powerpc64/powerpc64/locore.S b/sys/arch/powerpc64/powerpc64/locore.S
index c74b185651c..59c5cb5d2f8 100644
--- a/sys/arch/powerpc64/powerpc64/locore.S
+++ b/sys/arch/powerpc64/powerpc64/locore.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.S,v 1.47 2023/12/10 16:56:01 deraadt Exp $	*/
+/*	$OpenBSD: locore.S,v 1.48 2023/12/12 07:37:21 deraadt Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -42,11 +42,9 @@ sigcodecall:
 	sc
 	.globl sigcoderet
 sigcoderet:
-	li	%r0, SYS_exit
-	sc
 	.globl esigcode
 esigcode:
-
+	/* FALLTHROUGH */
 	.globl sigfill
 sigfill:
 	.long	0
diff --git a/sys/arch/riscv64/riscv64/locore.S b/sys/arch/riscv64/riscv64/locore.S
index f1f1f2e8be7..f7c3f0f01c5 100644
--- a/sys/arch/riscv64/riscv64/locore.S
+++ b/sys/arch/riscv64/riscv64/locore.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.S,v 1.16 2023/12/10 16:56:02 deraadt Exp $	*/
+/*	$OpenBSD: locore.S,v 1.17 2023/12/12 07:37:21 deraadt Exp $	*/
 
 /*-
  * Copyright (c) 2015-2018 Ruslan Bukin <br@bsdpad.com>
@@ -236,15 +236,6 @@ initstack:
 	.space	USPACE
 initstack_end:
 
-	.globl	sigfill
-sigfill:
-	unimp
-esigfill:
-	.globl	sigfillsiz
-sigfillsiz:
-	.data
-	.word	esigfill - sigfill
-
 	.text
 ENTRY(sigcode)
 	mv	a0, sp
@@ -255,13 +246,20 @@ sigcodecall:
 	ecall
 	.globl sigcoderet
 sigcoderet:
-	/* sigreturn failed, exit */
-	li	t0, SYS_exit
-	ecall
+	unimp
 END(sigcode)
 	.globl esigcode
 esigcode:
 
+	.globl	sigfill
+sigfill:
+	unimp
+esigfill:
+	.globl	sigfillsiz
+sigfillsiz:
+	.data
+	.word	esigfill - sigfill
+
 	.data
 	.global esym
 esym:
diff --git a/sys/arch/sh/sh/locore_subr.S b/sys/arch/sh/sh/locore_subr.S
index 2bd371ff887..944d1d2372e 100644
--- a/sys/arch/sh/sh/locore_subr.S
+++ b/sys/arch/sh/sh/locore_subr.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore_subr.S,v 1.18 2023/12/10 16:56:02 deraadt Exp $	*/
+/*	$OpenBSD: locore_subr.S,v 1.19 2023/12/12 07:37:21 deraadt Exp $	*/
 /*	$NetBSD: locore_subr.S,v 1.28 2006/01/23 22:52:09 uwe Exp $	*/
 
 /*
@@ -45,7 +45,7 @@
 
 #include "assym.h"
 
-#include <sys/syscall.h>	/* SYS_sigreturn, SYS_exit */
+#include <sys/syscall.h>	/* SYS_sigreturn */
 #include <sh/asm.h>
 #include <sh/locore.h>
 #include <sh/param.h>		/* UPAGES */
@@ -502,13 +502,11 @@ sigcodecall:
 	trapa	#0x80			/* and call sigreturn() */
 	.globl	sigcoderet
 sigcoderet:
-	mov.l	.L_SYS_exit, r0
-	trapa	#0x80			/* exit if sigreturn fails */
+	sleep		/* privileged -> illegal? */
 	/* NOTREACHED */
 
 	.align	2
 .L_SYS_sigreturn:	.long	SYS_sigreturn
-.L_SYS_exit:		.long	SYS_exit
 
 /* LINTSTUB: Var: char esigcode[1] */
 .globl	esigcode
diff --git a/sys/arch/sparc64/sparc64/locore.s b/sys/arch/sparc64/sparc64/locore.s
index 786bb4a7ace..a92c987562d 100644
--- a/sys/arch/sparc64/sparc64/locore.s
+++ b/sys/arch/sparc64/sparc64/locore.s
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.s,v 1.203 2023/12/10 16:56:02 deraadt Exp $	*/
+/*	$OpenBSD: locore.s,v 1.204 2023/12/12 07:37:21 deraadt Exp $	*/
 /*	$NetBSD: locore.s,v 1.137 2001/08/13 06:10:10 jdolecek Exp $	*/
 
 /*
@@ -5403,11 +5403,9 @@ sigcoderet:
 sigcodecall:
 	t	ST_SYSCALL		! sigreturn(scp)
 	! sigreturn does not return unless it fails
-	mov	SYS_exit, %g1		! exit(errno)
-	t	ST_SYSCALL
 	.globl	esigcode
 esigcode:
-
+	/* FALLTHROUGH */
 	.globl	sigfill
 sigfill:
 	unimp