Capture a repeated pattern into sysctl_securelevel_int function

A few variables in the kernel are only writeable before securelevel is
raised. It makes sense to handle them with less code.

OK sthen@ bluhm@

6 files changed, 33 insertions, 41 deletions

diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c
index 326f1c10253..08a20bf76ed 100644
--- a/sys/arch/amd64/amd64/machdep.c
+++ b/sys/arch/amd64/amd64/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.275 2021/10/06 15:46:03 claudio Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.276 2022/01/25 04:04:40 gnezdo Exp $	*/
 /*	$NetBSD: machdep.c,v 1.3 2003/05/07 22:58:18 fvdl Exp $	*/
 
 /*-
@@ -513,12 +513,8 @@ cpu_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 	case CPU_CPUVENDOR:
 		return (sysctl_rdstring(oldp, oldlenp, newp, cpu_vendor));
 	case CPU_KBDRESET:
-		if (securelevel > 0)
-			return (sysctl_rdint(oldp, oldlenp, newp,
-			    kbd_reset));
-		else
-			return (sysctl_int(oldp, oldlenp, newp, newlen,
-			    &kbd_reset));
+		return (sysctl_securelevel_int(oldp, oldlenp, newp, newlen,
+		    &kbd_reset));
 	case CPU_ALLOWAPERTURE:
 		if (namelen != 1)
 			return (ENOTDIR);		/* overloaded */
diff --git a/sys/arch/i386/i386/machdep.c b/sys/arch/i386/i386/machdep.c
index 0d32cd4edd7..cbc55378966 100644
--- a/sys/arch/i386/i386/machdep.c
+++ b/sys/arch/i386/i386/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.646 2021/10/06 15:46:03 claudio Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.647 2022/01/25 04:04:40 gnezdo Exp $	*/
 /*	$NetBSD: machdep.c,v 1.214 1996/11/10 03:16:17 thorpej Exp $	*/
 
 /*-
@@ -3617,12 +3617,8 @@ cpu_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 	case CPU_CPUFEATURE:
 		return (sysctl_rdint(oldp, oldlenp, newp, curcpu()->ci_feature_flags));
 	case CPU_KBDRESET:
-		if (securelevel > 0)
-			return (sysctl_rdint(oldp, oldlenp, newp,
-			    kbd_reset));
-		else
-			return (sysctl_int(oldp, oldlenp, newp, newlen,
-			    &kbd_reset));
+		return (sysctl_securelevel_int(oldp, oldlenp, newp, newlen,
+		    &kbd_reset));
 #if NPCKBC > 0 && NUKBD > 0
 	case CPU_FORCEUKBD:
 		{
diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index e71cdf5897d..6caeb627196 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sysctl.c,v 1.398 2021/12/23 10:17:01 bluhm Exp $	*/
+/*	$OpenBSD: kern_sysctl.c,v 1.399 2022/01/25 04:04:40 gnezdo Exp $	*/
 /*	$NetBSD: kern_sysctl.c,v 1.17 1996/05/20 17:49:05 mrg Exp $	*/
 
 /*-
@@ -473,14 +473,12 @@ kern_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 		return (0);
 #if NDT > 0
 	case KERN_ALLOWDT:
-		if (securelevel > 0)
-			return (sysctl_rdint(oldp, oldlenp, newp, allowdt));
-		return (sysctl_int(oldp, oldlenp, newp, newlen,  &allowdt));
+		return (sysctl_securelevel_int(oldp, oldlenp, newp, newlen,
+		    &allowdt));
 #endif
 	case KERN_ALLOWKMEM:
-		if (securelevel > 0)
-			return (sysctl_rdint(oldp, oldlenp, newp, allowkmem));
-		return (sysctl_int(oldp, oldlenp, newp, newlen, &allowkmem));
+		return (sysctl_securelevel_int(oldp, oldlenp, newp, newlen,
+		    &allowkmem));
 	case KERN_HOSTNAME:
 		error = sysctl_tstring(oldp, oldlenp, newp, newlen,
 		    hostname, sizeof(hostname));
@@ -757,10 +755,7 @@ hw_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 		return (sysctl_rdquad(oldp, oldlenp, newp,
 		    ptoa((psize_t)physmem - uvmexp.wired)));
 	case HW_ALLOWPOWERDOWN:
-		if (securelevel > 0)
-			return (sysctl_rdint(oldp, oldlenp, newp,
-			    allowpowerdown));
-		return (sysctl_int(oldp, oldlenp, newp, newlen,
+		return (sysctl_securelevel_int(oldp, oldlenp, newp, newlen,
 		    &allowpowerdown));
 #ifdef __HAVE_CPU_TOPOLOGY
 	case HW_SMT:
@@ -876,6 +871,18 @@ sysctl_rdint(void *oldp, size_t *oldlenp, void *newp, int val)
 }
 
 /*
+ * Selects between sysctl_rdint and sysctl_int according to securelevel.
+ */
+int
+sysctl_securelevel_int(void *oldp, size_t *oldlenp, void *newp, size_t newlen,
+    int *valp)
+{
+	if (securelevel > 0)
+		return (sysctl_rdint(oldp, oldlenp, newp, *valp));
+	return (sysctl_int(oldp, oldlenp, newp, newlen, valp));
+}
+
+/*
  * Read-only or bounded integer values.
  */
 int
@@ -2501,11 +2508,9 @@ sysctl_utc_offset(void *oldp, size_t *oldlenp, void *newp, size_t newlen)
 	int adjustment_seconds, error, new_offset_minutes, old_offset_minutes;
 
 	old_offset_minutes = utc_offset / 60;	/* seconds -> minutes */
-	if (securelevel > 0)
-		return sysctl_rdint(oldp, oldlenp, newp, old_offset_minutes);
-
 	new_offset_minutes = old_offset_minutes;
-	error = sysctl_int(oldp, oldlenp, newp, newlen, &new_offset_minutes);
+	error = sysctl_securelevel_int(oldp, oldlenp, newp, newlen,
+	     &new_offset_minutes);
 	if (error)
 		return error;
 	if (new_offset_minutes < -24 * 60 || new_offset_minutes > 24 * 60)
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 43a7cbd4ae9..069a65d51e0 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vfs_subr.c,v 1.313 2021/10/25 10:24:54 claudio Exp $	*/
+/*	$OpenBSD: vfs_subr.c,v 1.314 2022/01/25 04:04:40 gnezdo Exp $	*/
 /*	$NetBSD: vfs_subr.c,v 1.53 1996/04/22 01:39:13 christos Exp $	*/
 
 /*
@@ -1845,9 +1845,8 @@ fs_posix_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
 
 	switch (name[0]) {
 	case FS_POSIX_SETUID:
-		if (newp && securelevel > 0)
-			return (EPERM);
-		return(sysctl_int(oldp, oldlenp, newp, newlen, &suid_clear));
+		return (sysctl_securelevel_int(oldp, oldlenp, newp, newlen,
+		    &suid_clear));
 	default:
 		return (EOPNOTSUPP);
 	}
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index 9e7e20af30b..e9042d8e093 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_input.c,v 1.364 2021/11/22 13:47:10 bluhm Exp $	*/
+/*	$OpenBSD: ip_input.c,v 1.365 2022/01/25 04:04:40 gnezdo Exp $	*/
 /*	$NetBSD: ip_input.c,v 1.30 1996/03/16 23:53:58 christos Exp $	*/
 
 /*
@@ -1610,13 +1610,8 @@ ip_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 
 	switch (name[0]) {
 	case IPCTL_SOURCEROUTE:
-		/*
-		 * Don't allow this to change in a secure environment.
-		 */
-		if (newp && securelevel > 0)
-			return (EPERM);
 		NET_LOCK();
-		error = sysctl_int(oldp, oldlenp, newp, newlen,
+		error = sysctl_securelevel_int(oldp, oldlenp, newp, newlen,
 		    &ip_dosourceroute);
 		NET_UNLOCK();
 		return (error);
diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index 29f82bcece3..6ff6e3cffaf 100644
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sysctl.h,v 1.221 2022/01/11 23:59:55 jsg Exp $	*/
+/*	$OpenBSD: sysctl.h,v 1.222 2022/01/25 04:04:41 gnezdo Exp $	*/
 /*	$NetBSD: sysctl.h,v 1.16 1996/04/09 20:55:36 cgd Exp $	*/
 
 /*
@@ -1017,6 +1017,7 @@ typedef int (sysctlfn)(int *, u_int, void *, size_t *, void *, size_t, struct pr
 int sysctl_int_lower(void *, size_t *, void *, size_t, int *);
 int sysctl_int(void *, size_t *, void *, size_t, int *);
 int sysctl_rdint(void *, size_t *, void *, int);
+int sysctl_securelevel_int(void *, size_t *, void *, size_t, int *);
 int sysctl_int_bounded(void *, size_t *, void *, size_t, int *, int, int);
 int sysctl_bounded_arr(const struct sysctl_bounded_args *, u_int,
     int *, u_int, void *, size_t *, void *, size_t);