[PATCH AUTOSEL 5.6 084/606] ima: Fix return value of ima_write_policy()

[Sasha Levin]

From: Roberto Sassu <roberto.sassu at huawei.com>

[ Upstream commit 2e3a34e9f409ebe83d1af7cd2f49fca7af97dfac ]

This patch fixes the return value of ima_write_policy() when a new policy
is directly passed to IMA and the current policy requires appraisal of the
file containing the policy. Currently, if appraisal is not in ENFORCE mode,
ima_write_policy() returns 0 and leads user space applications to an
endless loop. Fix this issue by denying the operation regardless of the
appraisal mode.

Cc: stable at vger.kernel.org # 4.10.x
Fixes: 19f8a84713edc ("ima: measure and appraise the IMA policy itself")
Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>
Reviewed-by: Krzysztof Struczynski <krzysztof.struczynski at huawei.com>
Signed-off-by: Mimi Zohar <zohar at linux.ibm.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 security/integrity/ima/ima_fs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 2000e8df0301..68571c40d61f 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -340,8 +340,7 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
 				    "policy_update", "signed policy required",
 				    1, 0);
-		if (ima_appraise & IMA_APPRAISE_ENFORCE)
-			result = -EACCES;
+		result = -EACCES;
 	} else {
 		result = ima_parse_add_rule(data);
 	}
-- 
2.25.1