linux-kernel - [PATCH 09/12] module: move tainting until after a module hits our linked list

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Message-Id: <20230319212746.1783033-10-mcgrof@kernel.org>
Date:   Sun, 19 Mar 2023 14:27:43 -0700
From:   Luis Chamberlain <mcgrof@...nel.org>
To:     linux-modules@...r.kernel.org, linux-kernel@...r.kernel.org,
        pmladek@...e.com, david@...hat.com, petr.pavlu@...e.com,
        prarit@...hat.com
Cc:     christophe.leroy@...roup.eu, song@...nel.org, mcgrof@...nel.org
Subject: [PATCH 09/12] module: move tainting until after a module hits our linked list

It is silly to have taints spread out all over, we can just compromise
and add them if the module ever hit our linked list. Our sanity checkers
should just prevent crappy drivers / bogus ELF modules / etc and kconfig
options should be enough to let you *not* load things you don't want.

Signed-off-by: Luis Chamberlain <mcgrof@...nel.org>
---
 kernel/module/main.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/kernel/module/main.c b/kernel/module/main.c
index a3953ca18090..1aa71f82aca2 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2009,18 +2009,6 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
 	if (err)
 		return err;
 
-	/*
-	 * We are tainting your kernel *even* if you try to load
-	 * modules with possible taints and we fail to load these
-	 * modules for other reasons.
-	 *
-	 * We have a descrepancy though, see the other taints for
-	 * signature and those in check_module_license_and_versions().
-	 *
-	 * We should compromise and converge.
-	 */
-	module_augment_kernel_taints(mod, info);
-
 	return 0;
 }
 
@@ -2772,6 +2760,16 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	if (err)
 		goto free_module;
 
+	/*
+	 * We are tainting your kernel if your module gets into
+	 * the modules linked list somehow.
+	 *
+	 * We have a descrepancy though, see the other taints for
+	 * signature and those in check_module_license_and_versions().
+	 *
+	 * We should compromise and converge.
+	 */
+	module_augment_kernel_taints(mod, info);
 #ifdef CONFIG_MODULE_SIG
 	mod->sig_ok = info->sig_ok;
 	if (!mod->sig_ok) {
-- 
2.39.1