[PATCH] KEYS: trusted: Fix memory leak on object td

From: Colin King <colin.king@canonical.com>
To: James Bottomley <jejb@linux.ibm.com>,
	Jarkko Sakkinen <jarkko@kernel.org>,
	Mimi Zohar <zohar@linux.ibm.com>,
	David Howells <dhowells@redhat.com>,
	James Morris <jmorris@namei.org>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: [PATCH] KEYS: trusted: Fix memory leak on object td
Date: Fri, 30 Apr 2021 12:37:24 +0100	[thread overview]
Message-ID: <20210430113724.110746-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

Two error return paths are neglecting to free allocated object td,
causing a memory leak. Fix this by returning via the error return
path that securely kfree's td.

Fixes clang scan-build warning:
security/keys/trusted-keys/trusted_tpm1.c:496:10: warning: Potential
memory leak [unix.Malloc]

Fixes: 5df16caada3f ("KEYS: trusted: Fix incorrect handling of tpm_get_random()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 security/keys/trusted-keys/trusted_tpm1.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c
index 469394550801..aa108bea6739 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -493,10 +493,12 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
 
 	ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE);
 	if (ret < 0)
-		return ret;
+		goto out;
 
-	if (ret != TPM_NONCE_SIZE)
-		return -EIO;
+	if (ret != TPM_NONCE_SIZE) {
+		ret = -EIO;
+		goto out;
+	}
 
 	ordinal = htonl(TPM_ORD_SEAL);
 	datsize = htonl(datalen);
-- 
2.30.2

