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From:   trix@redhat.com
To:     paul@paul-moore.com, stephen.smalley.work@gmail.com,
        eparis@parisplace.org, omosnace@redhat.com, jeffv@google.com,
        rgb@redhat.com
Cc:     selinux@vger.kernel.org, linux-kernel@vger.kernel.org,
        Tom Rix <trix@redhat.com>
Subject: [PATCH 1/1] selinux: fix double free
Date:   Wed, 10 Jun 2020 11:10:21 -0700
Message-Id: <20200610181021.19209-2-trix@redhat.com>
In-Reply-To: <20200610181021.19209-1-trix@redhat.com>
References: <20200610181021.19209-1-trix@redhat.com>
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From: Tom Rix <trix@redhat.com>

Clang's static analysis tool reports these double free memory errors.

security/selinux/ss/services.c:2987:4: warning: Attempt to free released memory [unix.Malloc]
                        kfree(bnames[i]);
                        ^~~~~~~~~~~~~~~~
security/selinux/ss/services.c:2990:2: warning: Attempt to free released memory [unix.Malloc]
        kfree(bvalues);
        ^~~~~~~~~~~~~~

So improve the security_get_bools error handling by freeing these variables
and setting their return pointers to NULL and the return len to 0

Signed-off-by: Tom Rix <trix@redhat.com>
---
 security/selinux/ss/services.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 313919bd42f8..2dffae1feaff 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2888,8 +2888,12 @@ int security_get_bools(struct selinux_state *state,
 	if (*names) {
 		for (i = 0; i < *len; i++)
 			kfree((*names)[i]);
+		kfree(names);
 	}
 	kfree(*values);
+	*len = 0;
+	*names = NULL;
+	*values = NULL;
 	goto out;
 }
 
-- 
2.18.1