svn commit: r332395 - head/sys/kern

[Ian Lepore]

Author: ian
Date: Tue Apr 10 22:57:56 2018
New Revision: 332395
URL: https://svnweb.freebsd.org/changeset/base/332395

Log:
  Use explicit_bzero() when cleaning values out of the kernel environment.
  
  Sometimes the values contain geli passphrases being communicated from
  loader(8) to the kernel, and some day the compiler may decide to start
  eliding calls to memset() for a pointer which is not dereferenced again
  before being passed to free().

Modified:
  head/sys/kern/kern_environment.c

Modified: head/sys/kern/kern_environment.c
==============================================================================
--- head/sys/kern/kern_environment.c	Tue Apr 10 22:32:31 2018	(r332394)
+++ head/sys/kern/kern_environment.c	Tue Apr 10 22:57:56 2018	(r332395)
@@ -289,7 +289,7 @@ init_dynamic_kenv(void *data __unused)
 			if (i < KENV_SIZE) {
 				kenvp[i] = malloc(len, M_KENV, M_WAITOK);
 				strcpy(kenvp[i++], cp);
-				memset(cp, 0, strlen(cp));
+				explicit_bzero(cp, strlen(cp));
 			} else
 				printf(
 				"WARNING: too many kenv strings, ignoring %s\n",
@@ -308,7 +308,7 @@ freeenv(char *env)
 {
 
 	if (dynamic_kenv && env != NULL) {
-		memset(env, 0, strlen(env));
+		explicit_bzero(env, strlen(env));
 		free(env, M_KENV);
 	}
 }
@@ -486,7 +486,7 @@ kern_unsetenv(const char *name)
 			kenvp[i++] = kenvp[j];
 		kenvp[i] = NULL;
 		mtx_unlock(&kenv_lock);
-		memset(oldenv, 0, strlen(oldenv));
+		explicit_bzero(oldenv, strlen(oldenv));
 		free(oldenv, M_KENV);
 		return (0);
 	}