1 files changed, 92 insertions, 1 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 74bc195..68c564e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -58,6 +58,7 @@
 #include <linux/jump_label.h>
 #include <linux/pfn.h>
 #include <linux/bsearch.h>
+#include "module-internal.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/module.h>
@@ -102,6 +103,43 @@ static LIST_HEAD(modules);
 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 #endif /* CONFIG_KGDB_KDB */
 
+#ifdef CONFIG_MODULE_SIG
+#ifdef CONFIG_MODULE_SIG_FORCE
+static bool sig_enforce = true;
+#else
+static bool sig_enforce = false;
+
+static int param_set_bool_enable_only(const char *val,
+				      const struct kernel_param *kp)
+{
+	int err;
+	bool test;
+	struct kernel_param dummy_kp = *kp;
+
+	dummy_kp.arg = &test;
+
+	err = param_set_bool(val, &dummy_kp);
+	if (err)
+		return err;
+
+	/* Don't let them unset it once it's set! */
+	if (!test && sig_enforce)
+		return -EROFS;
+
+	if (test)
+		sig_enforce = true;
+	return 0;
+}
+
+static const struct kernel_param_ops param_ops_bool_enable_only = {
+	.set = param_set_bool_enable_only,
+	.get = param_get_bool,
+};
+#define param_check_bool_enable_only param_check_bool
+
+module_param(sig_enforce, bool_enable_only, 0644);
+#endif /* !CONFIG_MODULE_SIG_FORCE */
+#endif /* CONFIG_MODULE_SIG */
 
 /* Block module loading/unloading? */
 int modules_disabled = 0;
@@ -136,6 +174,7 @@ struct load_info {
 	unsigned long symoffs, stroffs;
 	struct _ddebug *debug;
 	unsigned int num_debug;
+	bool sig_ok;
 	struct {
 		unsigned int sym, str, mod, vers, info, pcpu;
 	} index;
@@ -2379,7 +2418,49 @@ static inline void kmemleak_load_module(const struct module *mod,
 }
 #endif
 
-/* Sets info->hdr and info->len. */
+#ifdef CONFIG_MODULE_SIG
+static int module_sig_check(struct load_info *info,
+			    const void *mod, unsigned long *len)
+{
+	int err = -ENOKEY;
+	const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
+	const void *p = mod, *end = mod + *len;
+
+	/* Poor man's memmem. */
+	while ((p = memchr(p, MODULE_SIG_STRING[0], end - p))) {
+		if (p + markerlen > end)
+			break;
+
+		if (memcmp(p, MODULE_SIG_STRING, markerlen) == 0) {
+			const void *sig = p + markerlen;
+			/* Truncate module up to signature. */
+			*len = p - mod;
+			err = mod_verify_sig(mod, *len, sig, end - sig);
+			break;
+		}
+		p++;
+	}
+
+	if (!err) {
+		info->sig_ok = true;
+		return 0;
+	}
+
+	/* Not having a signature is only an error if we're strict. */
+	if (err == -ENOKEY && !sig_enforce)
+		err = 0;
+
+	return err;
+}
+#else /* !CONFIG_MODULE_SIG */
+static int module_sig_check(struct load_info *info,
+			    void *mod, unsigned long *len)
+{
+	return 0;
+}
+#endif /* !CONFIG_MODULE_SIG */
+
+/* Sets info->hdr, info->len and info->sig_ok. */
 static int copy_and_check(struct load_info *info,
 			  const void __user *umod, unsigned long len,
 			  const char __user *uargs)
@@ -2399,6 +2480,10 @@ static int copy_and_check(struct load_info *info,
 		goto free_hdr;
 	}
 
+	err = module_sig_check(info, hdr, &len);
+	if (err)
+		goto free_hdr;
+
 	/* Sanity checks against insmoding binaries or wrong arch,
 	   weird elf version */
 	if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
@@ -2884,6 +2969,12 @@ static struct module *load_module(void __user *umod,
 		goto free_copy;
 	}
 
+#ifdef CONFIG_MODULE_SIG
+	mod->sig_ok = info.sig_ok;
+	if (!mod->sig_ok)
+		add_taint_module(mod, TAINT_FORCED_MODULE);
+#endif
+
 	/* Now module is in final location, initialize linked lists, etc. */
 	err = module_unload_init(mod);
 	if (err)