linux-kernel - [PATCH] tpm2_load

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Message-Id: <20210610094952.17068-1-find.dhiraj@gmail.com>
Date:   Thu, 10 Jun 2021 10:49:51 +0100
From:   Dhiraj Shah <find.dhiraj@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     find.dhiraj@...il.com, James Bottomley <jejb@...ux.ibm.com>,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Mimi Zohar <zohar@...ux.ibm.com>,
        David Howells <dhowells@...hat.com>,
        James Morris <jmorris@...ei.org>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        linux-integrity@...r.kernel.org, keyrings@...r.kernel.org,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] tpm2_load_command leaks memory

tpm2_key_decode allocates memory which is stored in blob and it's not freed.

Signed-off-by: Dhiraj Shah <find.dhiraj@...il.com>
---
 security/keys/trusted-keys/trusted_tpm2.c | 41 +++++++++++++++--------
 1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 0165da386289..52dd43bb8cdb 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -378,22 +378,31 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 	}
 
 	/* new format carries keyhandle but old format doesn't */
-	if (!options->keyhandle)
-		return -EINVAL;
+	if (!options->keyhandle) {
+		rc = -EINVAL;
+		goto err;
+	}
 
 	/* must be big enough for at least the two be16 size counts */
-	if (payload->blob_len < 4)
-		return -EINVAL;
+	if (payload->blob_len < 4) {
+		rc = -EINVAL;
+		goto err;
+	}
 
 	private_len = get_unaligned_be16(blob);
 
 	/* must be big enough for following public_len */
-	if (private_len + 2 + 2 > (payload->blob_len))
-		return -E2BIG;
+	if (private_len + 2 + 2 > (payload->blob_len)) {
+		rc = -E2BIG;
+		goto err;
+	}
 
 	public_len = get_unaligned_be16(blob + 2 + private_len);
-	if (private_len + 2 + public_len + 2 > payload->blob_len)
-		return -E2BIG;
+
+	if (private_len + 2 + public_len + 2 > payload->blob_len) {
+		rc = -E2BIG;
+		goto err;
+	}
 
 	pub = blob + 2 + private_len + 2;
 	/* key attributes are always at offset 4 */
@@ -406,13 +415,16 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 		payload->migratable = 1;
 
 	blob_len = private_len + public_len + 4;
-	if (blob_len > payload->blob_len)
-		return -E2BIG;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
-	if (rc)
-		return rc;
+	if (blob_len > payload->blob_len) {
+		rc = -E2BIG;
+		goto err;
+	}
 
+	if (tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD) != 0)
+		rc = -ENOMEM;
+		goto out;
+	}
 	tpm_buf_append_u32(&buf, options->keyhandle);
 	tpm2_buf_append_auth(&buf, TPM2_RS_PW,
 			     NULL /* nonce */, 0,
@@ -433,9 +445,10 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 			(__be32 *) &buf.data[TPM_HEADER_SIZE]);
 
 out:
+	tpm_buf_destroy(&buf);
+err:
 	if (blob != payload->blob)
 		kfree(blob);
-	tpm_buf_destroy(&buf);
 
 	if (rc > 0)
 		rc = -EPERM;
-- 
2.30.1 (Apple Git-130)