1 files changed, 9 insertions, 17 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 0e2da8695f8e..6085f5ef88ea 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2421,25 +2421,17 @@ static inline void kmemleak_load_module(const struct module *mod,
 
 #ifdef CONFIG_MODULE_SIG
 static int module_sig_check(struct load_info *info,
-                            const void *mod, unsigned long *len)
+                            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++;
+        unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
+        unsigned long len = *_len;
+
+        if (len > markerlen &&
+            memcmp(mod + len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
+                /* We truncate the module to discard the signature */
+                *_len -= markerlen;
+                err = mod_verify_sig(mod, _len);
         }
 
         if (!err) {