kmod: make usermodehelper path a const string

This is in preparation for making it so that usermode helper programs can't be changed, if desired, by userspace. We will tackle the mess of cleaning up the write-ability of argv and env later, that's going to take more work, for much less gain... Signed-off-by: Greg Kroah-Hartman <[email protected]>
laijs · Jan 19, 2017 · 6d2c5d6 · 6d2c5d6
1 parent 5593edf
commit 6d2c5d6
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Showing 2 changed files with 6 additions and 5 deletions.
diff --git a/include/linux/kmod.h b/include/linux/kmod.h
@@ -56,7 +56,7 @@ struct file;
 struct subprocess_info {
 	struct work_struct work;
 	struct completion *complete;
-	char *path;
+	const char *path;
 	char **argv;
 	char **envp;
 	int wait;
@@ -67,10 +67,11 @@ struct subprocess_info {
 };
 
 extern int
-call_usermodehelper(char *path, char **argv, char **envp, int wait);
+call_usermodehelper(const char *path, char **argv, char **envp, int wait);
 
 extern struct subprocess_info *
-call_usermodehelper_setup(char *path, char **argv, char **envp, gfp_t gfp_mask,
+call_usermodehelper_setup(const char *path, char **argv, char **envp,
+			  gfp_t gfp_mask,
 			  int (*init)(struct subprocess_info *info, struct cred *new),
 			  void (*cleanup)(struct subprocess_info *), void *data);
 

diff --git a/kernel/kmod.c b/kernel/kmod.c
@@ -516,7 +516,7 @@ static void helper_unlock(void)
  * Function must be runnable in either a process context or the
  * context in which call_usermodehelper_exec is called.
  */
-struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,
+struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv,
 		char **envp, gfp_t gfp_mask,
 		int (*init)(struct subprocess_info *info, struct cred *new),
 		void (*cleanup)(struct subprocess_info *info),
@@ -613,7 +613,7 @@ EXPORT_SYMBOL(call_usermodehelper_exec);
  * This function is the equivalent to use call_usermodehelper_setup() and
  * call_usermodehelper_exec().
  */
-int call_usermodehelper(char *path, char **argv, char **envp, int wait)
+int call_usermodehelper(const char *path, char **argv, char **envp, int wait)
 {
 	struct subprocess_info *info;
 	gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;