From c7fc24dc4420057f103afe8fc64524ebc25c5d37 Mon Sep 17 00:00:00 2001
From: Ralf Baechle <ralf@linux-mips.org>
Date: Tue, 25 Aug 1998 09:12:35 +0000
Subject:  o Merge with Linux 2.1.116.  o New Newport console code.  o New G364
 console code.

---
 kernel/kmod.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 11 deletions(-)

(limited to 'kernel/kmod.c')

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 7468e4382..ec0d85d32 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -14,14 +14,15 @@
 #include <linux/sched.h>
 #include <linux/types.h>
 #include <linux/unistd.h>
-#include <asm/smp_lock.h>
+#include <linux/smp_lock.h>
+#include <linux/signal.h>
+
 #include <asm/uaccess.h>
 
 /*
 	modprobe_path is set via /proc/sys.
 */
 char modprobe_path[256] = "/sbin/modprobe";
-static char * envp[] = { "HOME=/", "TERM=linux", "PATH=/usr/bin:/bin", NULL };
 
 /*
 	exec_modprobe is spawned from a kernel-mode user process,
@@ -33,20 +34,22 @@ static char * envp[] = { "HOME=/", "TERM=linux", "PATH=/usr/bin:/bin", NULL };
 #define task_init task[smp_num_cpus]
 
 static inline void
-use_init_file_context(void) {
+use_init_file_context(void)
+{
 	lock_kernel();
 
 	/* don't use the user's root, use init's root instead */
 	exit_fs(current);	/* current->fs->count--; */
 	current->fs = task_init->fs;
-	current->fs->count++;
+	atomic_inc(&current->fs->count);
 
 	unlock_kernel();
 }
 
 static int exec_modprobe(void * module_name)
 {
-	char *argv[] = { modprobe_path, "-s", "-k", (char*)module_name, NULL};
+	static char * envp[] = { "HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
+	char *argv[] = { modprobe_path, "-s", "-k", (char*)module_name, NULL };
 	int i;
 
 	use_init_file_context();
@@ -63,11 +66,21 @@ static int exec_modprobe(void * module_name)
 	spin_unlock_irq(&current->sigmask_lock);
 
 	for (i = 0; i < current->files->max_fds; i++ ) {
-	    if (current->files->fd[i]) close(i);
+		if (current->files->fd[i]) close(i);
 	}
 
-	set_fs(KERNEL_DS);	/* Allow execve args to be in kernel space. */
+	/* Drop the "current user" thing */
+	free_uid(current);
+
+	/* Give kmod all privileges.. */
 	current->uid = current->euid = current->fsuid = 0;
+	cap_set_full(current->cap_inheritable);
+	cap_set_full(current->cap_effective);
+
+	/* Allow execve args to be in kernel space. */
+	set_fs(KERNEL_DS);
+
+	/* Go, go, go... */
 	if (execve(modprobe_path, argv, envp) < 0) {
 		printk(KERN_ERR
 		       "kmod: failed to exec %s -s -k %s, errno = %d\n",
@@ -85,14 +98,36 @@ int request_module(const char * module_name)
 {
 	int pid;
 	int waitpid_result;
+	sigset_t tmpsig;
+
+	/* Don't allow request_module() before the root fs is mounted!  */
+	if ( ! current->fs->root ) {
+		printk(KERN_ERR "request_module[%s]: Root fs not mounted\n",
+			module_name);
+		return -EPERM;
+	}
 
-	pid = kernel_thread(exec_modprobe, (void*) module_name,
-			    CLONE_FS | SIGCHLD);
+	pid = kernel_thread(exec_modprobe, (void*) module_name, CLONE_FS);
 	if (pid < 0) {
-		printk(KERN_ERR "kmod: fork failed, errno %d\n", -pid);
+		printk(KERN_ERR "request_module[%s]: fork failed, errno %d\n", module_name, -pid);
 		return pid;
 	}
-	waitpid_result = waitpid(pid, NULL, 0);
+
+	/* Block everything but SIGKILL/SIGSTOP */
+	spin_lock_irq(&current->sigmask_lock);
+	tmpsig = current->blocked;
+	siginitset(&current->blocked, ~(sigmask(SIGKILL)|sigmask(SIGSTOP)));
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+
+	waitpid_result = waitpid(pid, NULL, __WCLONE);
+
+	/* Allow signals again.. */
+	spin_lock_irq(&current->sigmask_lock);
+	current->blocked = tmpsig;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+
 	if (waitpid_result != pid) {
 		printk (KERN_ERR "kmod: waitpid(%d,NULL,0) failed, returning %d.\n",
 			pid, waitpid_result);
-- 
cgit v1.2.3