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From:   Muhammad Usama Anjum <usama.anjum@collabora.com>
To:     John Johansen <john.johansen@canonical.com>,
        Paul Moore <paul@paul-moore.com>,
        James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>
Cc:     Muhammad Usama Anjum <usama.anjum@collabora.com>,
        kernel@collabora.com, kernel-janitors@vger.kernel.org,
        apparmor@lists.ubuntu.com, linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] apparmor: store return value of unpack_perms_table() to signed variable
Date:   Tue,  4 Oct 2022 13:45:15 +0500
Message-Id: <20221004084515.659441-1-usama.anjum@collabora.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The unpack_perms_table() can return error which is negative value. Store
the return value to a signed variable. policy->size is unsigned
variable. It shouldn't be used to store the return status.

Fixes: 2d6b2dea7f3c ("apparmor: add the ability for policy to specify a permission table")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
---
 security/apparmor/policy_unpack.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c
index 45c9dfdc8e0d..09f316943951 100644
--- a/security/apparmor/policy_unpack.c
+++ b/security/apparmor/policy_unpack.c
@@ -734,14 +734,18 @@ static int unpack_pdb(struct aa_ext *e, struct aa_policydb *policy,
 {
 	void *pos = e->pos;
 	int i, flags, error = -EPROTO;
+	ssize_t size;
 
-	policy->size = unpack_perms_table(e, &policy->perms);
-	if (policy->size < 0) {
-		error = policy->size;
+	size = unpack_perms_table(e, &policy->perms);
+	if (size < 0) {
+		error = size;
 		policy->perms = NULL;
 		*info = "failed to unpack - perms";
 		goto fail;
-	} else if (policy->perms) {
+	}
+	policy->size = size;
+
+	if (policy->perms) {
 		/* perms table present accept is index */
 		flags = TO_ACCEPT1_FLAG(YYTD_DATA32);
 	} else {
-- 
2.30.2