1 files changed, 25 insertions, 28 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 0e2da8695f8..6e48c3a4359 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2293,12 +2293,17 @@ static void layout_symtab(struct module *mod, struct load_info *info)
         src = (void *)info->hdr + symsect->sh_offset;
         nsrc = symsect->sh_size / sizeof(*src);
 
+        /* strtab always starts with a nul, so offset 0 is the empty string. */
+        strtab_size = 1;
+
         /* Compute total space required for the core symbols' strtab. */
-        for (ndst = i = strtab_size = 1; i < nsrc; ++i, ++src)
-                if (is_core_symbol(src, info->sechdrs, info->hdr->e_shnum)) {
-                        strtab_size += strlen(&info->strtab[src->st_name]) + 1;
+        for (ndst = i = 0; i < nsrc; i++) {
+                if (i == 0 ||
+                    is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
+                        strtab_size += strlen(&info->strtab[src[i].st_name])+1;
                         ndst++;
                 }
+        }
 
         /* Append room for core symbols at end of core part. */
         info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
@@ -2332,15 +2337,15 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
         mod->core_symtab = dst = mod->module_core + info->symoffs;
         mod->core_strtab = s = mod->module_core + info->stroffs;
         src = mod->symtab;
-        *dst = *src;
         *s++ = 0;
-        for (ndst = i = 1; i < mod->num_symtab; ++i, ++src) {
-                if (!is_core_symbol(src, info->sechdrs, info->hdr->e_shnum))
-                        continue;
-
-                dst[ndst] = *src;
-                dst[ndst++].st_name = s - mod->core_strtab;
-                s += strlcpy(s, &mod->strtab[src->st_name], KSYM_NAME_LEN) + 1;
+        for (ndst = i = 0; i < mod->num_symtab; i++) {
+                if (i == 0 ||
+                    is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
+                        dst[ndst] = src[i];
+                        dst[ndst++].st_name = s - mod->core_strtab;
+                        s += strlcpy(s, &mod->strtab[src[i].st_name],
+                                     KSYM_NAME_LEN) + 1;
+                }
         }
         mod->core_num_syms = ndst;
 }
@@ -2421,25 +2426,17 @@ 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) {