libkmod: enforce non-null memory in kmod_elf_new()

In practise none of our code-paths will use a NULL pointer so we might
as well enforce that. To stay aligned with the kernel behaviour update
our init_module() preload library to return EFAULT... Should we get
confused and pass NULL in the future.

Signed-off-by: Emil Velikov <[email protected]>
Link: #346
Signed-off-by: Lucas De Marchi <[email protected]>

Author: evelikov

libkmod/libkmod-elf.c

@@ -317,11 +317,6 @@ struct kmod_elf *kmod_elf_new(const void *memory, off_t size)
 	assert_cc(sizeof(uint32_t) == sizeof(Elf32_Word));
 	assert_cc(sizeof(uint32_t) == sizeof(Elf64_Word));
 
-	if (!memory) {
-		errno = -EINVAL;
-		return NULL;
-	}
-
 	elf = malloc(sizeof(struct kmod_elf));
 	if (elf == NULL) {
 		return NULL;

libkmod/libkmod-internal.h

@@ -152,7 +152,7 @@ struct kmod_modversion {
 	const char *symbol;
 };
 
-struct kmod_elf *kmod_elf_new(const void *memory, off_t size);
+_nonnull_all_ struct kmod_elf *kmod_elf_new(const void *memory, off_t size);
 _nonnull_all_ void kmod_elf_unref(struct kmod_elf *elf);
 _must_check_ _nonnull_all_ const void *kmod_elf_get_memory(const struct kmod_elf *elf);
 _must_check_ _nonnull_all_ int kmod_elf_get_modinfo_strings(const struct kmod_elf *elf, char ***array);

testsuite/init_module.c

@@ -234,6 +234,11 @@ long init_module(void *mem, unsigned long len, const char *args)
 
 	init_retcodes();
 
+	if (mem == NULL) {
+		errno = EFAULT;
+		return -1;
+	}
+
 	elf = kmod_elf_new(mem, len);
 	if (elf == NULL)
 		return -1;