From: Roberto Sassu <roberto.sassu@huawei.com>
To: <zohar@linux.ibm.com>, <tiwai@suse.de>
Cc: <linux-integrity@vger.kernel.org>,
<linux-security-module@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <silviu.vlasceanu@huawei.com>,
Roberto Sassu <roberto.sassu@huawei.com>,
<stable@vger.kernel.org>
Subject: [PATCH 1/2] ima: Directly assign the ima_default_policy pointer to ima_rules
Date: Wed, 3 Jun 2020 17:08:20 +0200 [thread overview]
Message-ID: <20200603150821.8607-1-roberto.sassu@huawei.com> (raw)
This patch prevents the following oops:
[ 10.771813] BUG: kernel NULL pointer dereference, address: 0000000000000
[...]
[ 10.779790] RIP: 0010:ima_match_policy+0xf7/0xb80
[...]
[ 10.798576] Call Trace:
[ 10.798993] ? ima_lsm_policy_change+0x2b0/0x2b0
[ 10.799753] ? inode_init_owner+0x1a0/0x1a0
[ 10.800484] ? _raw_spin_lock+0x7a/0xd0
[ 10.801592] ima_must_appraise.part.0+0xb6/0xf0
[ 10.802313] ? ima_fix_xattr.isra.0+0xd0/0xd0
[ 10.803167] ima_must_appraise+0x4f/0x70
[ 10.804004] ima_post_path_mknod+0x2e/0x80
[ 10.804800] do_mknodat+0x396/0x3c0
It occurs when there is a failure during IMA initialization, and
ima_init_policy() is not called. IMA hooks still call ima_match_policy()
but ima_rules is NULL. This patch prevents the crash by directly assigning
the ima_default_policy pointer to ima_rules when ima_rules is defined. This
wouldn't alter the existing behavior, as ima_rules is always set at the end
of ima_init_policy().
Cc: stable@vger.kernel.org # 3.7.x
Fixes: 07f6a79415d7d ("ima: add appraise action keywords and default rules")
Reported-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
security/integrity/ima/ima_policy.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index ef7f68cc935e..e493063a3c34 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -204,7 +204,7 @@ static struct ima_rule_entry *arch_policy_entry __ro_after_init;
static LIST_HEAD(ima_default_rules);
static LIST_HEAD(ima_policy_rules);
static LIST_HEAD(ima_temp_rules);
-static struct list_head *ima_rules;
+static struct list_head *ima_rules = &ima_default_rules;
/* Pre-allocated buffer used for matching keyrings. */
static char *ima_keyrings;
@@ -768,7 +768,6 @@ void __init ima_init_policy(void)
ARRAY_SIZE(default_appraise_rules),
IMA_DEFAULT_POLICY);
- ima_rules = &ima_default_rules;
ima_update_policy_flag();
}
--
2.17.1
next reply other threads:[~2020-06-03 15:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-03 15:08 Roberto Sassu [this message]
2020-06-03 15:08 ` [PATCH 2/2] ima: Call ima_calc_boot_aggregate() in ima_eventdigest_init() Roberto Sassu
2020-06-03 22:03 ` Mimi Zohar
2020-06-04 19:12 ` Bruno Meneguele
2020-06-04 19:35 ` Mimi Zohar
2020-06-04 19:57 ` Bruno Meneguele
2020-06-03 21:30 ` [PATCH 1/2] ima: Directly assign the ima_default_policy pointer to ima_rules Mimi Zohar
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