1 files changed, 68 insertions, 0 deletions

diff --git a/init/main.c b/init/main.c
index 9d3a7b8..8ac3833 100644
--- a/init/main.c
+++ b/init/main.c
@@ -77,6 +77,7 @@
 #include <linux/sched_clock.h>
 #include <linux/context_tracking.h>
 #include <linux/random.h>
+#include <linux/list.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -665,6 +666,70 @@ static void __init do_ctors(void)
 bool initcall_debug;
 core_param(initcall_debug, initcall_debug, bool, 0644);
 
+#ifdef CONFIG_KALLSYMS
+struct blacklist_entry {
+	struct list_head next;
+	char *buf;
+};
+
+static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
+
+static int __init initcall_blacklist(char *str)
+{
+	char *str_entry;
+	struct blacklist_entry *entry;
+
+	/* str argument is a comma-separated list of functions */
+	do {
+		str_entry = strsep(&str, ",");
+		if (str_entry) {
+			pr_debug("blacklisting initcall %s\n", str_entry);
+			entry = alloc_bootmem(sizeof(*entry));
+			entry->buf = alloc_bootmem(strlen(str_entry) + 1);
+			strcpy(entry->buf, str_entry);
+			list_add(&entry->next, &blacklisted_initcalls);
+		}
+	} while (str_entry);
+
+	return 0;
+}
+
+static bool __init_or_module initcall_blacklisted(initcall_t fn)
+{
+	struct list_head *tmp;
+	struct blacklist_entry *entry;
+	char *fn_name;
+
+	fn_name = kasprintf(GFP_KERNEL, "%pf", fn);
+	if (!fn_name)
+		return false;
+
+	list_for_each(tmp, &blacklisted_initcalls) {
+		entry = list_entry(tmp, struct blacklist_entry, next);
+		if (!strcmp(fn_name, entry->buf)) {
+			pr_debug("initcall %s blacklisted\n", fn_name);
+			kfree(fn_name);
+			return true;
+		}
+	}
+
+	kfree(fn_name);
+	return false;
+}
+#else
+static int __init initcall_blacklist(char *str)
+{
+	pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
+	return 0;
+}
+
+static bool __init_or_module initcall_blacklisted(initcall_t fn)
+{
+	return false;
+}
+#endif
+__setup("initcall_blacklist=", initcall_blacklist);
+
 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 {
 	ktime_t calltime, delta, rettime;
@@ -689,6 +754,9 @@ int __init_or_module do_one_initcall(initcall_t fn)
 	int ret;
 	char msgbuf[64];
 
+	if (initcall_blacklisted(fn))
+		return -EPERM;
+
 	if (initcall_debug)
 		ret = do_one_initcall_debug(fn);
 	else