linux-kernel - [PATCH] livepatch: robustify klp_register

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 7 Apr 2016 18:06:25 +0200 (CEST)
From:	Jiri Kosina <jikos@...nel.org>
To:	Dan Carpenter <dan.carpenter@...cle.com>
cc:	jeyu@...hat.com, Josh Poimboeuf <jpoimboe@...hat.com>,
	Miroslav Benes <mbenes@...e.cz>,
	Petr Mladek <pmladek@...e.com>, live-patching@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] livepatch: robustify klp_register_patch() API error
 checking

From: Jiri Kosina <jkosina@...e.cz>

Commit 425595a7fc20 ("livepatch: reuse module loader code to write 
relocations") adds a possibility of dereferncing pointers supplied by the 
consumer of the livepatch API before sanity (NULL) checking them (patch 
and patch->mod).

Spotted by smatch tool.

Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Jiri Kosina <jkosina@...e.cz>
---
 kernel/livepatch/core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index eb5db6e..28c37fa 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -876,6 +876,9 @@ int klp_register_patch(struct klp_patch *patch)
 {
 	int ret;
 
+	if (!patch || !patch->mod)
+		return -EINVAL;
+
 	if (!is_livepatch_module(patch->mod)) {
 		pr_err("module %s is not marked as a livepatch module",
 		       patch->mod->name);
@@ -885,9 +888,6 @@ int klp_register_patch(struct klp_patch *patch)
 	if (!klp_initialized())
 		return -ENODEV;
 
-	if (!patch || !patch->mod)
-		return -EINVAL;
-
 	/*
 	 * A reference is taken on the patch module to prevent it from being
 	 * unloaded.  Right now, we don't allow patch modules to unload since

-- 
Jiri Kosina
SUSE Labs