0003-add-CONFIG_READONLY_USERMODEHELPER-support-for-lots-.patch

From dd1c428188101dd5428aa7bb9ed1a1329a052763 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 15 Dec 2016 13:09:59 -0800
Subject: [PATCH 3/3] add CONFIG_READONLY_USERMODEHELPER support for lots of
 places.

Dynamic usermode helper should be stopped, so support it...
---
 arch/x86/kernel/cpu/mcheck/mce.c |   12 ++++++++----
 drivers/block/drbd/drbd_int.h    |    2 +-
 drivers/block/drbd/drbd_main.c   |    4 +++-
 drivers/block/drbd/drbd_nl.c     |    4 ++--
 drivers/video/fbdev/uvesafb.c    |   17 +++++++++++------
 fs/nfs/cache_lib.c               |   12 +++++++++---
 include/linux/kobject.h          |    3 ++-
 include/linux/reboot.h           |    3 ++-
 kernel/ksysfs.c                  |    6 +++++-
 kernel/reboot.c                  |    2 +-
 kernel/sysctl.c                  |    4 ++++
 lib/kobject_uevent.c             |    4 ++--
 12 files changed, 50 insertions(+), 23 deletions(-)

--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -2292,15 +2292,16 @@ static ssize_t set_bank(struct device *s
 }
 
 static ssize_t
-show_trigger(struct device *s, struct device_attribute *attr, char *buf)
+trigger_show(struct device *s, struct device_attribute *attr, char *buf)
 {
 	strcpy(buf, mce_helper);
 	strcat(buf, "\n");
 	return strlen(mce_helper) + 1;
 }
 
-static ssize_t set_trigger(struct device *s, struct device_attribute *attr,
-				const char *buf, size_t siz)
+#ifndef CONFIG_READONLY_USERMODEHELPER
+static ssize_t trigger_store(struct device *s, struct device_attribute *attr,
+			     const char *buf, size_t siz)
 {
 	char *p;
 
@@ -2313,6 +2314,10 @@ static ssize_t set_trigger(struct device
 
 	return strlen(mce_helper) + !!p;
 }
+static DEVICE_ATTR_RW(trigger);
+#else
+static DEVICE_ATTR_RO(trigger);
+#endif
 
 static ssize_t set_ignore_ce(struct device *s,
 			     struct device_attribute *attr,
@@ -2370,7 +2375,6 @@ static ssize_t store_int_with_restart(st
 	return ret;
 }
 
-static DEVICE_ATTR(trigger, 0644, show_trigger, set_trigger);
 static DEVICE_INT_ATTR(tolerant, 0644, mca_cfg.tolerant);
 static DEVICE_INT_ATTR(monarch_timeout, 0644, mca_cfg.monarch_timeout);
 static DEVICE_BOOL_ATTR(dont_log_ce, 0644, mca_cfg.dont_log_ce);
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -75,7 +75,7 @@ extern int fault_rate;
 extern int fault_devs;
 #endif
 
-extern char drbd_usermode_helper[];
+extern char __ro_umh drbd_usermode_helper[];
 
 
 /* This is used to stop/restart our threads.
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -109,9 +109,11 @@ int proc_details;       /* Detail level
 
 /* Module parameter for setting the user mode helper program
  * to run. Default is /sbin/drbdadm */
-char drbd_usermode_helper[80] = "/sbin/drbdadm";
+char __ro_umh drbd_usermode_helper[80] = "/sbin/drbdadm";
 
+#ifndef CONFIG_READONLY_USERMODEHELPER
 module_param_string(usermode_helper, drbd_usermode_helper, sizeof(drbd_usermode_helper), 0644);
+#endif
 
 /* in 2.6.x, our device mapping and config info contains our virtual gendisks
  * as member "struct gendisk *vdisk;"
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -344,7 +344,7 @@ int drbd_khelper(struct drbd_device *dev
 			 (char[60]) { }, /* address */
 			NULL };
 	char mb[14];
-	char *argv[] = {drbd_usermode_helper, cmd, mb, NULL };
+	char *argv[] = {(char *)drbd_usermode_helper, cmd, mb, NULL };
 	struct drbd_connection *connection = first_peer_device(device)->connection;
 	struct sib_info sib;
 	int ret;
@@ -396,7 +396,7 @@ enum drbd_peer_state conn_khelper(struct
 			 (char[60]) { }, /* address */
 			NULL };
 	char *resource_name = connection->resource->name;
-	char *argv[] = {drbd_usermode_helper, cmd, resource_name, NULL };
+	char *argv[] = {(char *)drbd_usermode_helper, cmd, resource_name, NULL };
 	int ret;
 
 	setup_khelper_env(connection, envp);
--- a/drivers/video/fbdev/uvesafb.c
+++ b/drivers/video/fbdev/uvesafb.c
@@ -30,7 +30,7 @@ static struct cb_id uvesafb_cn_id = {
 	.idx = CN_IDX_V86D,
 	.val = CN_VAL_V86D_UVESAFB
 };
-static char v86d_path[PATH_MAX] = "/sbin/v86d";
+static char __ro_umh v86d_path[PATH_MAX] = "/sbin/v86d";
 static char v86d_started;	/* has v86d been started by uvesafb? */
 
 static const struct fb_fix_screeninfo uvesafb_fix = {
@@ -114,7 +114,7 @@ static int uvesafb_helper_start(void)
 	};
 
 	char *argv[] = {
-		v86d_path,
+		(char *)v86d_path,
 		NULL,
 	};
 
@@ -1883,19 +1883,22 @@ static int uvesafb_setup(char *options)
 }
 #endif /* !MODULE */
 
-static ssize_t show_v86d(struct device_driver *dev, char *buf)
+static ssize_t v86d_show(struct device_driver *dev, char *buf)
 {
 	return snprintf(buf, PAGE_SIZE, "%s\n", v86d_path);
 }
 
-static ssize_t store_v86d(struct device_driver *dev, const char *buf,
+#ifndef CONFIG_READONLY_USERMODEHELPER
+static ssize_t v86d_store(struct device_driver *dev, const char *buf,
 		size_t count)
 {
 	strncpy(v86d_path, buf, PATH_MAX);
 	return count;
 }
-
-static DRIVER_ATTR(v86d, S_IRUGO | S_IWUSR, show_v86d, store_v86d);
+static DRIVER_ATTR_RW(v86d);
+#else
+static DRIVER_ATTR_RO(v86d);
+#endif
 
 static int uvesafb_init(void)
 {
@@ -2017,8 +2020,10 @@ MODULE_PARM_DESC(mode_option,
 module_param(vbemode, ushort, 0);
 MODULE_PARM_DESC(vbemode,
 	"VBE mode number to set, overrides the 'mode' option");
+#ifndef CONFIG_READONLY_USERMODEHELPER
 module_param_string(v86d, v86d_path, PATH_MAX, 0660);
 MODULE_PARM_DESC(v86d, "Path to the v86d userspace helper.");
+#endif
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Michal Januszewski <spock@gentoo.org>");
--- a/fs/nfs/cache_lib.c
+++ b/fs/nfs/cache_lib.c
@@ -20,13 +20,16 @@
 #define NFS_CACHE_UPCALL_PATHLEN 256
 #define NFS_CACHE_UPCALL_TIMEOUT 15
 
-static char nfs_cache_getent_prog[NFS_CACHE_UPCALL_PATHLEN] =
+static char __ro_umh nfs_cache_getent_prog[NFS_CACHE_UPCALL_PATHLEN] =
 				"/sbin/nfs_cache_getent";
 static unsigned long nfs_cache_getent_timeout = NFS_CACHE_UPCALL_TIMEOUT;
 
+#ifndef CONFIG_READONLY_USERMODEHELPER
 module_param_string(cache_getent, nfs_cache_getent_prog,
 		sizeof(nfs_cache_getent_prog), 0600);
 MODULE_PARM_DESC(cache_getent, "Path to the client cache upcall program");
+#endif
+
 module_param_named(cache_getent_timeout, nfs_cache_getent_timeout, ulong, 0600);
 MODULE_PARM_DESC(cache_getent_timeout, "Timeout (in seconds) after which "
 		"the cache upcall is assumed to have failed");
@@ -39,7 +42,7 @@ int nfs_cache_upcall(struct cache_detail
 		NULL
 	};
 	char *argv[] = {
-		nfs_cache_getent_prog,
+		(char *)nfs_cache_getent_prog,
 		cd->name,
 		entry_name,
 		NULL
@@ -48,15 +51,18 @@ int nfs_cache_upcall(struct cache_detail
 
 	if (nfs_cache_getent_prog[0] == '\0')
 		goto out;
-	ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+	ret = call_usermodehelper(nfs_cache_getent_prog, argv, envp,
+				  UMH_WAIT_EXEC);
 	/*
 	 * Disable the upcall mechanism if we're getting an ENOENT or
 	 * EACCES error. The admin can re-enable it on the fly by using
 	 * sysfs to set the 'cache_getent' parameter once the problem
 	 * has been fixed.
 	 */
+#ifndef CONFIG_READONLY_USERMODEHELPER
 	if (ret == -ENOENT || ret == -EACCES)
 		nfs_cache_getent_prog[0] = '\0';
+#endif
 out:
 	return ret > 0 ? 0 : ret;
 }
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -27,6 +27,7 @@
 #include <linux/wait.h>
 #include <linux/atomic.h>
 #include <linux/workqueue.h>
+#include <linux/kmod.h>
 
 #define UEVENT_HELPER_PATH_LEN		256
 #define UEVENT_NUM_ENVP			32	/* number of env pointers */
@@ -34,7 +35,7 @@
 
 #ifdef CONFIG_UEVENT_HELPER
 /* path to the userspace helper executed on an event */
-extern char uevent_helper[];
+extern char __ro_umh uevent_helper[];
 #endif
 
 /* counter to tag the uevent, read only except for the kobject core */
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -3,6 +3,7 @@
 
 
 #include <linux/notifier.h>
+#include <linux/kmod.h>
 #include <uapi/linux/reboot.h>
 
 #define SYS_DOWN	0x0001	/* Notify of system down */
@@ -68,7 +69,7 @@ extern int C_A_D; /* for sysctl */
 void ctrl_alt_del(void);
 
 #define POWEROFF_CMD_PATH_LEN	256
-extern char poweroff_cmd[POWEROFF_CMD_PATH_LEN];
+extern char __ro_umh poweroff_cmd[];
 
 extern void orderly_poweroff(bool force);
 extern void orderly_reboot(void);
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -44,6 +44,7 @@ static ssize_t uevent_helper_show(struct
 {
 	return sprintf(buf, "%s\n", uevent_helper);
 }
+#ifndef CONFIG_READONLY_USERMODEHELPER
 static ssize_t uevent_helper_store(struct kobject *kobj,
 				   struct kobj_attribute *attr,
 				   const char *buf, size_t count)
@@ -57,7 +58,10 @@ static ssize_t uevent_helper_store(struc
 	return count;
 }
 KERNEL_ATTR_RW(uevent_helper);
-#endif
+#else
+KERNEL_ATTR_RO(uevent_helper);
+#endif	/* CONFIG_READONLY_USERMODEHELPER */
+#endif	/* CONFIG_UEVENT_HELPER */
 
 #ifdef CONFIG_PROFILING
 static ssize_t profiling_show(struct kobject *kobj,
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -386,7 +386,7 @@ void ctrl_alt_del(void)
 		kill_cad_pid(SIGINT, 1);
 }
 
-char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
+char __ro_umh poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
 static const char reboot_cmd[] = "/sbin/reboot";
 
 static int run_cmd(const char *cmd)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -663,6 +663,7 @@ static struct ctl_table kern_table[] = {
 	},
 #endif
 #ifdef CONFIG_UEVENT_HELPER
+#ifndef CONFIG_READONLY_USERMODEHELPER
 	{
 		.procname	= "hotplug",
 		.data		= &uevent_helper,
@@ -671,6 +672,7 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dostring,
 	},
 #endif
+#endif
 #ifdef CONFIG_CHR_DEV_SG
 	{
 		.procname	= "sg-big-buff",
@@ -1080,6 +1082,7 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 #endif
+#ifndef CONFIG_READONLY_USERMODEHELPER
 	{
 		.procname	= "poweroff_cmd",
 		.data		= &poweroff_cmd,
@@ -1087,6 +1090,7 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dostring,
 	},
+#endif
 #ifdef CONFIG_KEYS
 	{
 		.procname	= "keys",
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -29,7 +29,7 @@
 
 u64 uevent_seqnum;
 #ifdef CONFIG_UEVENT_HELPER
-char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
+char __ro_umh uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
 #endif
 #ifdef CONFIG_NET
 struct uevent_sock {
@@ -137,7 +137,7 @@ static int init_uevent_argv(struct kobj_
 		return -ENOMEM;
 	}
 
-	env->argv[0] = uevent_helper;
+	env->argv[0] = (char *)uevent_helper;
 	env->argv[1] = &env->buf[env->buflen];
 	env->argv[2] = NULL;