[PATCH] get rid of exec_usermodehelper, replace with call_usermodehelper

Urban Widmark points out that modprobe calls system() in many
configurations, which drops privs since request_module() doesn't
set ruid and rguid.

This gets rid of exec_usermodehelper and makes everyone use
call_usermodehelper, which has a new "wait" flag.

arch/i386/mach-voyager/voyager_thread.c

@@ -57,7 +57,7 @@ voyager_thread_start(void)
 }
 
 static int
-execute_helper(void *string)
+execute(const char *string)
 {
 	int ret;
 
@@ -74,22 +74,13 @@ execute_helper(void *string)
 		NULL,
 	};
 
-	if((ret = exec_usermodehelper(argv[0], argv, envp)) < 0) {
-		printk(KERN_ERR "Voyager failed to execute \"%s\"\n",
-		       (char *)string);
+	if ((ret = call_usermodehelper(argv[0], argv, envp, 1)) != 0) {
+		printk(KERN_ERR "Voyager failed to run \"%s\": %i\n",
+		       string, ret);
 	}
 	return ret;
 }
 
-static void
-execute(char *string)
-{
-	if(kernel_thread(execute_helper, (void *)string, CLONE_VFORK | SIGCHLD) < 0) {
-		printk(KERN_ERR "Voyager failed to fork before exec of \"%s\"\n",
-		       string);
-	}
-}
-
 static void
 check_from_kernel(void)
 {

drivers/acpi/thermal.c

@@ -436,7 +436,7 @@ acpi_thermal_call_usermode (
 	envp[0] = "HOME=/";
 	envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
 	
-	call_usermodehelper(argv[0], argv, envp);
+	call_usermodehelper(argv[0], argv, envp, 0);
 
 	return_VALUE(0);
 }

drivers/base/hotplug.c

@@ -114,7 +114,7 @@ static int do_hotplug (struct device *dev, char *argv1, const char *action,
 
 	pr_debug ("%s: %s %s %s %s %s %s\n", __FUNCTION__, argv [0], argv[1],
 		  envp[0], envp[1], envp[2], envp[3]);
-	retval = call_usermodehelper (argv [0], argv, envp);
+	retval = call_usermodehelper (argv [0], argv, envp, 0);
 	if (retval)
 		pr_debug ("%s - call_usermodehelper returned %d\n",
 			  __FUNCTION__, retval);

drivers/bluetooth/bt3c_cs.c

@@ -24,18 +24,14 @@
 #include <linux/config.h>
 #include <linux/module.h>
 
-#define __KERNEL_SYSCALLS__
-
 #include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/sched.h>
-#include <linux/delay.h>
 #include <linux/timer.h>
 #include <linux/errno.h>
-#include <linux/unistd.h>
 #include <linux/ptrace.h>
 #include <linux/ioport.h>
 #include <linux/spinlock.h>
@@ -405,7 +401,6 @@ void bt3c_interrupt(int irq, void *dev_inst, struct pt_regs *regs)
 
 
 
-
 /* ======================== HCI interface ======================== */
 
 
@@ -489,65 +484,23 @@ static int bt3c_hci_ioctl(struct hci_dev *hdev, unsigned int cmd, unsigned long
 
 
 #define FW_LOADER  "/sbin/bluefw"
-static int errno;
-
-
-static int bt3c_fw_loader_exec(void *dev)
-{
-	char *argv[] = { FW_LOADER, "pccard", dev, NULL };
-	char *envp[] = { "HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
-	int err;
-
-	err = exec_usermodehelper(FW_LOADER, argv, envp);
-	if (err)
-		printk(KERN_WARNING "bt3c_cs: Failed to exec \"%s pccard %s\".\n", FW_LOADER, (char *)dev);
-
-	return err;
-}
 
 
 static int bt3c_firmware_load(bt3c_info_t *info)
 {
-	sigset_t tmpsig;
 	char dev[16];
-	pid_t pid;
-	int result;
+	int err;
 
-	/* Check if root fs is mounted */
-	if (!current->fs->root) {
-		printk(KERN_WARNING "bt3c_cs: Root filesystem is not mounted.\n");
-		return -EPERM;
-	}
+	char *argv[] = { FW_LOADER, "pccard", dev, NULL };
+	char *envp[] = { "HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
 
 	sprintf(dev, "%04x", info->link.io.BasePort1);
 
-	pid = kernel_thread(bt3c_fw_loader_exec, (void *)dev, 0);
-	if (pid < 0) {
-		printk(KERN_WARNING "bt3c_cs: Forking of kernel thread failed (errno=%d).\n", -pid);
-		return pid;
-	}
-
-	/* Block signals, everything but SIGKILL/SIGSTOP */
-	spin_lock_irq(&current->sighand->siglock);
-	tmpsig = current->blocked;
-	siginitsetinv(&current->blocked, sigmask(SIGKILL) | sigmask(SIGSTOP));
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
-
-	result = waitpid(pid, NULL, __WCLONE);
-
-	/* Allow signals again */
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = tmpsig;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
-
-	if (result != pid) {
-		printk(KERN_WARNING "bt3c_cs: Waiting for pid %d failed (errno=%d).\n", pid, -result);
-		return -result;
-	}
+	err = call_usermodehelper(FW_LOADER, argv, envp, 1);
+	if (err)
+		printk(KERN_WARNING "bt3c_cs: Failed to run \"%s pccard %s\" (errno=%d).\n", FW_LOADER, dev, err);
 
-	return 0;
+	return err;
 }
 
 

drivers/ieee1394/nodemgr.c

@@ -786,7 +786,7 @@ static void nodemgr_call_policy(char *verb, struct unit_directory *ud)
 #ifdef CONFIG_IEEE1394_VERBOSEDEBUG
 	HPSB_DEBUG("NodeMgr: %s %s %016Lx", argv[0], verb, (long long unsigned)ud->ne->guid);
 #endif
-	value = call_usermodehelper(argv[0], argv, envp);
+	value = call_usermodehelper(argv[0], argv, envp, 0);
 	kfree(buf);
 	kfree(envp);
 	if (value != 0)

drivers/input/input.c

@@ -383,7 +383,7 @@ static void input_call_hotplug(char *verb, struct input_dev *dev)
 		argv[0], argv[1], envp[0], envp[1], envp[2], envp[3], envp[4]);
 #endif
 
-	value = call_usermodehelper(argv [0], argv, envp);
+	value = call_usermodehelper(argv [0], argv, envp, 0);
 
 	kfree(buf);
 	kfree(envp);

drivers/isdn/hardware/eicon/divasmain.c

@@ -263,7 +263,7 @@ static void diva_adapter_trapped(void *context)
 		pdpc->card_failed = 0;
 		argv[2] = &adapter[0];
 
-		ret = call_usermodehelper(argv[0], argv, envp);
+		ret = call_usermodehelper(argv[0], argv, envp, 0);
 
 		if (ret) {
 			printk(KERN_ERR

drivers/net/hamradio/baycom_epp.c

@@ -369,15 +369,14 @@ static char eppconfig_path[256] = "/usr/sbin/eppfpga";
 
 static char *envp[] = { "HOME=/", "TERM=linux", "PATH=/usr/bin:/bin", NULL };
 
-static int errno;
-
-static int exec_eppfpga(void *b)
+/* eppconfig: called during ifconfig up to configure the modem */
+static int eppconfig(struct baycom_state *bc)
 {
-	struct baycom_state *bc = (struct baycom_state *)b;
 	char modearg[256];
 	char portarg[16];
-        char *argv[] = { eppconfig_path, "-s", "-p", portarg, "-m", modearg, NULL};
-        int i;
+        char *argv[] = { eppconfig_path, "-s", "-p", portarg, "-m", modearg,
+			 NULL };
+        int ret;
 
 	/* set up arguments */
 	sprintf(modearg, "%sclk,%smodem,fclk=%d,bps=%d,divider=%d%s,extstat",
@@ -388,39 +387,7 @@ static int exec_eppfpga(void *b)
 	sprintf(portarg, "%ld", bc->pdev->port->base);
 	printk(KERN_DEBUG "%s: %s -s -p %s -m %s\n", bc_drvname, eppconfig_path, portarg, modearg);
 
-	i = exec_usermodehelper(eppconfig_path, argv, envp);
-	if (i < 0) {
-                printk(KERN_ERR "%s: failed to exec %s -s -p %s -m %s, errno = %d\n",
-                       bc_drvname, eppconfig_path, portarg, modearg, i);
-                return i;
-        }
-        return 0;
-}
-
-
-/* eppconfig: called during ifconfig up to configure the modem */
-
-static int eppconfig(struct baycom_state *bc)
-{
-        int i, pid, r;
-	mm_segment_t fs;
-
-        pid = kernel_thread(exec_eppfpga, bc, CLONE_FS);
-        if (pid < 0) {
-                printk(KERN_ERR "%s: fork failed, errno %d\n", bc_drvname, -pid);
-                return pid;
-        }
-	fs = get_fs();
-        set_fs(KERNEL_DS);      /* Allow i to be in kernel space. */
-	r = waitpid(pid, &i, __WCLONE);
-	set_fs(fs);
-        if (r != pid) {
-                printk(KERN_ERR "%s: waitpid(%d) failed, returning %d\n",
-		       bc_drvname, pid, r);
-		return -1;
-        }
-	printk(KERN_DEBUG "%s: eppfpga returned %d\n", bc_drvname, i);
-	return i;
+	return call_usermodehelper(eppconfig_path, argv, envp, 1);
 }
 
 /* ---------------------------------------------------------------------- */

drivers/pnp/pnpbios/core.c

@@ -602,7 +602,7 @@ static int pnp_dock_event(int dock, struct pnp_docking_station_info *info)
 		info->location_id, info->serial, info->capabilities);
 	envp[i] = 0;
 	
-	value = call_usermodehelper (argv [0], argv, envp);
+	value = call_usermodehelper (argv [0], argv, envp, 0);
 	kfree (buf);
 	kfree (envp);
 	return 0;

include/linux/kmod.h

@@ -21,6 +21,7 @@
 
 #include <linux/config.h>
 #include <linux/errno.h>
+#include <linux/compiler.h>
 
 #ifdef CONFIG_KMOD
 extern int request_module(const char * name);
@@ -29,8 +30,7 @@ static inline int request_module(const char * name) { return -ENOSYS; }
 #endif
 
 #define try_then_request_module(x, mod) ((x) ?: request_module(mod), (x))
-extern int exec_usermodehelper(char *program_path, char *argv[], char *envp[]);
-extern int call_usermodehelper(char *path, char *argv[], char *envp[]);
+extern int call_usermodehelper(char *path, char *argv[], char *envp[], int wait);
 
 #ifdef CONFIG_HOTPLUG
 extern char hotplug_path [];

net/bluetooth/hci_core.c

@@ -114,7 +114,7 @@ static int hci_run_hotplug(char *dev, char *action)
 	envp[3] = astr;
 	envp[4] = NULL;
 	
-	return call_usermodehelper(argv[0], argv, envp);
+	return call_usermodehelper(argv[0], argv, envp, 0);
 }
 #else
 #define hci_run_hotplug(A...)

net/core/dev.c

@@ -2942,6 +2942,6 @@ static int net_run_sbin_hotplug(struct net_device *dev, char *action)
 	envp [i++] = action_str;
 	envp [i] = 0;
 
-	return call_usermodehelper(argv [0], argv, envp);
+	return call_usermodehelper(argv [0], argv, envp, 0);
 }
 #endif