From: Emil Velikov <emil.l.velikov@gmail.com>
Date: Wed, 7 May 2025 18:50:06 +0000 (+0100)
Subject: libkmod: enforce non-null memory in kmod_elf_new()
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1b110b9bde5627ca9ed10900eb746c518cd1d56e;p=thirdparty%2Fkmod.git

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 <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/346
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
---

diff --git a/libkmod/libkmod-elf.c b/libkmod/libkmod-elf.c
index 4590543c..9b2ceca7 100644
--- a/libkmod/libkmod-elf.c
+++ b/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;
diff --git a/libkmod/libkmod-internal.h b/libkmod/libkmod-internal.h
index 8d322b65..3761ea18 100644
--- a/libkmod/libkmod-internal.h
+++ b/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);
diff --git a/testsuite/init_module.c b/testsuite/init_module.c
index a8fa58bb..ccb43b0c 100644
--- a/testsuite/init_module.c
+++ b/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;