[PATCH] Module length calculation fix and module with no init fix

Fixes miscalculation of required module size due to alignment issues of
first section after common, and also doesn't think that no init section
is an allocation failure.

kernel/module.c

@@ -592,14 +592,17 @@ static void *copy_section(const char *name,
 {
 	void *dest;
 	unsigned long *use;
+	unsigned long max;
 
 	/* Only copy to init section if there is one */
 	if (strstr(name, ".init") && mod->module_init) {
 		dest = mod->module_init;
 		use = &used->init_size;
+		max = mod->init_size;
 	} else {
 		dest = mod->module_core;
 		use = &used->core_size;
+		max = mod->core_size;
 	}
 
 	/* Align up */
@@ -607,6 +610,9 @@ static void *copy_section(const char *name,
 	dest += *use;
 	*use += sechdr->sh_size;
 
+	if (*use > max)
+		return ERR_PTR(-ENOEXEC);
+
 	/* May not actually be in the file (eg. bss). */
 	if (sechdr->sh_type != SHT_NOBITS)
 		memcpy(dest, base + sechdr->sh_offset, sechdr->sh_size);
@@ -773,9 +779,10 @@ static void simplify_symbols(Elf_Shdr *sechdrs,
 /* Get the total allocation size of the init and non-init sections */
 static struct sizes get_sizes(const Elf_Ehdr *hdr,
 			      const Elf_Shdr *sechdrs,
-			      const char *secstrings)
+			      const char *secstrings,
+			      unsigned long common_length)
 {
-	struct sizes ret = { 0, 0 };
+	struct sizes ret = { 0, common_length };
 	unsigned i;
 
 	/* Everything marked ALLOC (this includes the exported
@@ -933,10 +940,9 @@ static struct module *load_module(void *umod,
 	mod->live = 0;
 	module_unload_init(mod);
 
-	/* How much space will we need?  (Common area in core) */
-	sizes = get_sizes(hdr, sechdrs, secstrings);
+	/* How much space will we need?  (Common area in first) */
 	common_length = read_commons(hdr, &sechdrs[symindex]);
-	sizes.core_size += common_length;
+	sizes = get_sizes(hdr, sechdrs, secstrings, common_length);
 
 	/* Set these up, and allow archs to manipulate them. */
 	mod->core_size = sizes.core_size;
@@ -963,7 +969,7 @@ static struct module *load_module(void *umod,
 	mod->module_core = ptr;
 
 	ptr = module_alloc(mod->init_size);
-	if (!ptr) {
+	if (!ptr && mod->init_size) {
 		err = -ENOMEM;
 		goto free_core;
 	}