Merge branch 'modules-next' of git://git.kernel.org/pub/scm/linux/ker…

…nel/git/mcgrof/linux

Pull module updates from Luis Chamberlain:
 "The biggest change here is in-kernel support for module decompression.
  This change is being made to help support LSMs like LoadPin as
  otherwise it loses link between the source of kernel module on the
  disk and binary blob that is being loaded into the kernel.

  kmod decompression is still done by userspace even with this is done,
  both because there are no measurable gains in not doing so and as it
  adds a secondary extra check for validating the module before loading
  it into the kernel.

  The rest of the changes are minor, the only other change worth
  mentionin there is Jessica Yu is now bowing out of maintenance of
  modules as she's taking a break from work.

  While there were other changes posted for modules, those have not yet
  received much review of testing so I'm not yet comfortable in merging
  any of those changes yet."

* 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  module: fix signature check failures when using in-kernel decompression
  kernel: Fix spelling mistake "compresser" -> "compressor"
  MAINTAINERS: add mailing lists for kmod and modules
  module.h: allow #define strings to work with MODULE_IMPORT_NS
  module: add in-kernel support for decompressing
  MAINTAINERS: Remove myself as modules maintainer
  module: Remove outdated comment

MAINTAINERS

@@ -10705,6 +10705,7 @@ F:	samples/kmemleak/kmemleak-test.c
 KMOD KERNEL MODULE LOADER - USERMODE HELPER
 M:	Luis Chamberlain <[email protected]>
 L:	[email protected]
+L:	[email protected]
 S:	Maintained
 F:	include/linux/kmod.h
 F:	kernel/kmod.c
@@ -12994,9 +12995,10 @@ F:	drivers/media/dvb-frontends/mn88473*
 
 MODULE SUPPORT
 M:	Luis Chamberlain <[email protected]>
-M:	Jessica Yu <[email protected]>
+L:	[email protected]
+L:	[email protected]
 S:	Maintained
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux.git modules-next
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git modules-next
 F:	include/linux/module.h
 F:	kernel/module.c
 

include/linux/module.h

@@ -290,7 +290,8 @@ extern typeof(name) __mod_##type##__##name##_device_table		\
  * files require multiple MODULE_FIRMWARE() specifiers */
 #define MODULE_FIRMWARE(_firmware) MODULE_INFO(firmware, _firmware)
 
-#define MODULE_IMPORT_NS(ns) MODULE_INFO(import_ns, #ns)
+#define _MODULE_IMPORT_NS(ns)	MODULE_INFO(import_ns, #ns)
+#define MODULE_IMPORT_NS(ns)	_MODULE_IMPORT_NS(ns)
 
 struct notifier_block;
 

include/uapi/linux/module.h

@@ -5,5 +5,6 @@
 /* Flags for sys_finit_module: */
 #define MODULE_INIT_IGNORE_MODVERSIONS	1
 #define MODULE_INIT_IGNORE_VERMAGIC	2
+#define MODULE_INIT_COMPRESSED_FILE	4
 
 #endif /* _UAPI_LINUX_MODULE_H */

init/Kconfig

@@ -2278,6 +2278,19 @@ config MODULE_COMPRESS_ZSTD
 
 endchoice
 
+config MODULE_DECOMPRESS
+	bool "Support in-kernel module decompression"
+	depends on MODULE_COMPRESS_GZIP || MODULE_COMPRESS_XZ
+	select ZLIB_INFLATE if MODULE_COMPRESS_GZIP
+	select XZ_DEC if MODULE_COMPRESS_XZ
+	help
+
+	  Support for decompressing kernel modules by the kernel itself
+	  instead of relying on userspace to perform this task. Useful when
+	  load pinning security policy is enabled.
+
+	  If unsure, say N.
+
 config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
 	bool "Allow loading of modules with missing namespace imports"
 	help

kernel/Makefile

@@ -67,6 +67,7 @@ obj-y += up.o
 endif
 obj-$(CONFIG_UID16) += uid16.o
 obj-$(CONFIG_MODULES) += module.o
+obj-$(CONFIG_MODULE_DECOMPRESS) += module_decompress.o
 obj-$(CONFIG_MODULE_SIG) += module_signing.o
 obj-$(CONFIG_MODULE_SIG_FORMAT) += module_signature.o
 obj-$(CONFIG_KALLSYMS) += kallsyms.o

kernel/module-internal.h

@@ -22,10 +22,29 @@ struct load_info {
 	bool sig_ok;
 #ifdef CONFIG_KALLSYMS
 	unsigned long mod_kallsyms_init_off;
+#endif
+#ifdef CONFIG_MODULE_DECOMPRESS
+	struct page **pages;
+	unsigned int max_pages;
+	unsigned int used_pages;
 #endif
 	struct {
 		unsigned int sym, str, mod, vers, info, pcpu;
 	} index;
 };
 
 extern int mod_verify_sig(const void *mod, struct load_info *info);
+
+#ifdef CONFIG_MODULE_DECOMPRESS
+int module_decompress(struct load_info *info, const void *buf, size_t size);
+void module_decompress_cleanup(struct load_info *info);
+#else
+static inline int module_decompress(struct load_info *info,
+				    const void *buf, size_t size)
+{
+	return -EOPNOTSUPP;
+}
+static inline void module_decompress_cleanup(struct load_info *info)
+{
+}
+#endif

kernel/module.c

@@ -958,7 +958,6 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
 		}
 	}
 
-	/* Stop the machine so refcounts can't move and disable module. */
 	ret = try_stop_module(mod, flags, &forced);
 	if (ret != 0)
 		goto out;
@@ -2884,12 +2883,13 @@ static int module_sig_check(struct load_info *info, int flags)
 	const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
 	const char *reason;
 	const void *mod = info->hdr;
-
+	bool mangled_module = flags & (MODULE_INIT_IGNORE_MODVERSIONS |
+				       MODULE_INIT_IGNORE_VERMAGIC);
 	/*
-	 * Require flags == 0, as a module with version information
-	 * removed is no longer the module that was signed
+	 * Do not allow mangled modules as a module with version information
+	 * removed is no longer the module that was signed.
 	 */
-	if (flags == 0 &&
+	if (!mangled_module &&
 	    info->len > markerlen &&
 	    memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
 		/* We truncate the module to discard the signature */
@@ -3174,9 +3174,12 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
 	return err;
 }
 
-static void free_copy(struct load_info *info)
+static void free_copy(struct load_info *info, int flags)
 {
-	vfree(info->hdr);
+	if (flags & MODULE_INIT_COMPRESSED_FILE)
+		module_decompress_cleanup(info);
+	else
+		vfree(info->hdr);
 }
 
 static int rewrite_section_headers(struct load_info *info, int flags)
@@ -4125,7 +4128,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	}
 
 	/* Get rid of temporary copy. */
-	free_copy(info);
+	free_copy(info, flags);
 
 	/* Done! */
 	trace_module_load(mod);
@@ -4174,7 +4177,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 
 	module_deallocate(mod, info);
  free_copy:
-	free_copy(info);
+	free_copy(info, flags);
 	return err;
 }
 
@@ -4201,7 +4204,8 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
 SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 {
 	struct load_info info = { };
-	void *hdr = NULL;
+	void *buf = NULL;
+	int len;
 	int err;
 
 	err = may_init_module();
@@ -4211,15 +4215,24 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 	pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags);
 
 	if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS
-		      |MODULE_INIT_IGNORE_VERMAGIC))
+		      |MODULE_INIT_IGNORE_VERMAGIC
+		      |MODULE_INIT_COMPRESSED_FILE))
 		return -EINVAL;
 
-	err = kernel_read_file_from_fd(fd, 0, &hdr, INT_MAX, NULL,
+	len = kernel_read_file_from_fd(fd, 0, &buf, INT_MAX, NULL,
 				       READING_MODULE);
-	if (err < 0)
-		return err;
-	info.hdr = hdr;
-	info.len = err;
+	if (len < 0)
+		return len;
+
+	if (flags & MODULE_INIT_COMPRESSED_FILE) {
+		err = module_decompress(&info, buf, len);
+		vfree(buf); /* compressed data is no longer needed */
+		if (err)
+			return err;
+	} else {
+		info.hdr = buf;
+		info.len = len;
+	}
 
 	return load_module(&info, uargs, flags);
 }