Fix linux compat breakage: can't copyin() from kernel-space, so

move that out of i386_set_threadbase(), and have clone() pass NULL
to fork1() for the child func argument so that it gets the child
proc pointer.

Report and verification by pirofti@, heavy lifting by matthew@

4 files changed, 23 insertions, 19 deletions

diff --git a/sys/arch/i386/i386/linux_machdep.c b/sys/arch/i386/i386/linux_machdep.c
index 96b0ecb52e3..c9c8a5c5b00 100644
--- a/sys/arch/i386/i386/linux_machdep.c
+++ b/sys/arch/i386/i386/linux_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: linux_machdep.c,v 1.40 2011/07/05 04:48:01 guenther Exp $	*/
+/*	$OpenBSD: linux_machdep.c,v 1.41 2011/08/03 16:11:31 guenther Exp $	*/
 /*	$NetBSD: linux_machdep.c,v 1.29 1996/05/03 19:42:11 christos Exp $	*/
 
 /*
@@ -653,7 +653,7 @@ linux_sys_set_thread_area(struct proc *p, void *v, register_t *retval)
 	} else if (ldesc.entry_number != GUGS_SEL)
 		return EINVAL;
 
-	return i386_set_threadbase(p, &SCARG(uap, desc)->base_addr, TSEG_GS);
+	return i386_set_threadbase(p, SCARG(uap, desc)->base_addr, TSEG_GS);
 }
 
 int
diff --git a/sys/arch/i386/i386/sys_machdep.c b/sys/arch/i386/i386/sys_machdep.c
index cfc7827c347..0289edbaf0b 100644
--- a/sys/arch/i386/i386/sys_machdep.c
+++ b/sys/arch/i386/i386/sys_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sys_machdep.c,v 1.29 2011/04/15 15:08:19 chl Exp $	*/
+/*	$OpenBSD: sys_machdep.c,v 1.30 2011/08/03 16:11:31 guenther Exp $	*/
 /*	$NetBSD: sys_machdep.c,v 1.28 1996/05/03 19:42:29 christos Exp $	*/
 
 /*-
@@ -72,8 +72,6 @@ extern struct vm_map *kernel_map;
 int i386_iopl(struct proc *, void *, register_t *);
 int i386_get_ioperm(struct proc *, void *, register_t *);
 int i386_set_ioperm(struct proc *, void *, register_t *);
-int i386_get_threadbase(struct proc *, void *, int);
-int i386_set_threadbase(struct proc *, void *, int);
 
 #ifdef USER_LDT
 
@@ -405,15 +403,10 @@ i386_get_threadbase(struct proc *p, void *args, int which)
 }
 
 int
-i386_set_threadbase(struct proc *p, void *args, int which)
+i386_set_threadbase(struct proc *p, uint32_t base, int which)
 {
-	int error;
-	uint32_t base;
 	struct segment_descriptor *sdp;
 
-	if ((error = copyin(args, &base, sizeof(base))) != 0)
-		return error;
-
 	/*
 	 * We can't place a limit on the segment used by the library
 	 * thread register (%gs) because the ELF ABI for i386 places
@@ -472,16 +465,28 @@ sys_sysarch(struct proc *p, void *v, register_t *retval)
 		break;
 
 	case I386_SET_FSBASE:
-		error = i386_set_threadbase(p, SCARG(uap, parms), TSEG_FS);
+	      {
+		uint32_t base;
+
+		if ((error = copyin(SCARG(uap, parms), &base, sizeof(base))))
+			break;
+		error = i386_set_threadbase(p, base, TSEG_FS);
 		break;
+	      }
 
 	case I386_GET_GSBASE:
 		error = i386_get_threadbase(p, SCARG(uap, parms), TSEG_GS);
 		break;
 
 	case I386_SET_GSBASE:
-		error = i386_set_threadbase(p, SCARG(uap, parms), TSEG_GS);
+	      {
+		uint32_t base;
+
+		if ((error = copyin(SCARG(uap, parms), &base, sizeof(base))))
+			break;
+		error = i386_set_threadbase(p, base, TSEG_GS);
 		break;
+	      }
 
 	default:
 		error = EINVAL;
diff --git a/sys/arch/i386/include/sysarch.h b/sys/arch/i386/include/sysarch.h
index 04e50fab3bd..116325310cd 100644
--- a/sys/arch/i386/include/sysarch.h
+++ b/sys/arch/i386/include/sysarch.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sysarch.h,v 1.8 2011/04/04 21:50:41 pirofti Exp $	*/
+/*	$OpenBSD: sysarch.h,v 1.9 2011/08/03 16:11:31 guenther Exp $	*/
 /*	$NetBSD: sysarch.h,v 1.8 1996/01/08 13:51:44 mycroft Exp $	*/
 
 #ifndef _MACHINE_SYSARCH_H_
@@ -55,7 +55,7 @@ int i386_set_gsbase(void *);
 int sysarch(int, void *);
 #else
 int i386_get_threadbase(struct proc *, void *, int);
-int i386_set_threadbase(struct proc *, void *, int);
+int i386_set_threadbase(struct proc *, uint32_t, int);
 #endif
 
 #endif /* !_MACHINE_SYSARCH_H_ */
diff --git a/sys/compat/linux/linux_sched.c b/sys/compat/linux/linux_sched.c
index 61a4b5b98ad..14b00c23bf8 100644
--- a/sys/compat/linux/linux_sched.c
+++ b/sys/compat/linux/linux_sched.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: linux_sched.c,v 1.10 2011/04/05 15:44:40 pirofti Exp $	*/
+/*	$OpenBSD: linux_sched.c,v 1.11 2011/08/03 16:11:31 guenther Exp $	*/
 /*	$NetBSD: linux_sched.c,v 1.6 2000/05/28 05:49:05 thorpej Exp $	*/
 
 /*-
@@ -177,7 +177,7 @@ linux_sys_clone(struct proc *p, void *v, register_t *retval)
 	 * that makes this adjustment is a noop.
 	 */
 	error = fork1(p, sig, flags, SCARG(uap, stack), 0, linux_child_return,
-	    p, retval, NULL);
+	    NULL, retval, NULL);
 	if (error)
 		return error;
 
@@ -407,8 +407,7 @@ linux_child_return(void *arg)
 	struct proc *p = (struct proc *)arg;
 	struct linux_emuldata *emul = p->p_emuldata;
 
-	if (i386_set_threadbase(p, &emul->my_tls_base, TSEG_GS))
-		return;
+	i386_set_threadbase(p, emul->my_tls_base, TSEG_GS);
 
 	if (emul->my_set_tid) {
 		pid_t pid = p->p_pid + THREAD_PID_OFFSET;