Patch "module: Invalidate signatures on force-loaded modules" has been added to the 4.7-stable tree

This is a note to let you know that I've just added the patch titled

module: Invalidate signatures on force-loaded modules

to the 4.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
module-invalidate-signatures-on-force-loaded-modules.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ben Hutchings <[email protected]>
Date: Thu, 28 Apr 2016 09:24:01 +0930
Subject: module: Invalidate signatures on force-loaded modules

From: Ben Hutchings <[email protected]>

commit bca014caaa6130e57f69b5bf527967aa8ee70fdd upstream.

Signing a module should only make it trusted by the specific kernel it was built for, not anything else. Loading a signed module meant for a kernel with a different ABI could have interesting effects. Therefore, treat all signatures as invalid when a module is force-loaded.

---
 kernel/module.c |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

@@ -2687,13 +2687,18 @@ static inline void kmemleak_load_module(
 #endif
 
 #ifdef CONFIG_MODULE_SIG
-static int module_sig_check(struct load_info *info)
+static int module_sig_check(struct load_info *info, int flags)
 {
 	int err = -ENOKEY;
 	const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
 	const void *mod = info->hdr;
 
-	if (info->len > markerlen &&
+	/*
+	 * Require flags == 0, as a module with version information
+	 * removed is no longer the module that was signed
+	 */
+	if (flags == 0 &&
+	    info->len > markerlen &&
 	    memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
 		/* We truncate the module to discard the signature */
 		info->len -= markerlen;

@@ -2712,7 +2717,7 @@ static int module_sig_check(struct load_
 	return err;
 }
 #else /* !CONFIG_MODULE_SIG */
-static int module_sig_check(struct load_info *info)
+static int module_sig_check(struct load_info *info, int flags)
 {
 	return 0;
 }

@@ -3498,7 +3503,7 @@ static int load_module(struct load_info
 	long err;
 	char *after_dashes;
 
-	err = module_sig_check(info);
+	err = module_sig_check(info, flags);
 	if (err)
 		goto free_copy;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.7/module-invalidate-signatures-on-force-loaded-modules.patch queue-4.7/documentation-module-signing.txt-note-need-for-version-info-if-reusing-a-key.patch