tpm: Check size of response before accessing data

Make sure that we have not received less bytes than what is indicated
in the header of the TPM response. Also, check the number of bytes in
the response before accessing its data.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>

1 files changed, 49 insertions, 17 deletions

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 6eda2395f2cf..a0199f18f7fb 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -248,6 +248,9 @@ static const u8 tpm2_ordinal_duration[TPM2_CC_LAST - TPM2_CC_FIRST + 1] = {
 	(sizeof(struct tpm_input_header) + \
 	 sizeof(struct tpm2_pcr_read_in))
 
+#define TPM2_PCR_READ_RESP_BODY_SIZE \
+	 sizeof(struct tpm2_pcr_read_out)
+
 static const struct tpm_input_header tpm2_pcrread_header = {
 	.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
 	.length = cpu_to_be32(TPM2_PCR_READ_IN_SIZE),
@@ -280,8 +283,9 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
 	       sizeof(cmd.params.pcrread_in.pcr_select));
 	cmd.params.pcrread_in.pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
 
-	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0,
-			      "attempting to read a pcr value");
+	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
+			      TPM2_PCR_READ_RESP_BODY_SIZE,
+			      0, "attempting to read a pcr value");
 	if (rc == 0) {
 		buf = cmd.params.pcrread_out.digest;
 		memcpy(res_buf, buf, TPM_DIGEST_SIZE);
@@ -327,7 +331,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash)
 	cmd.params.pcrextend_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
 	memcpy(cmd.params.pcrextend_in.digest, hash, TPM_DIGEST_SIZE);
 
-	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0,
+	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0,
 			      "attempting extend a PCR value");
 
 	return rc;
@@ -356,7 +360,7 @@ static const struct tpm_input_header tpm2_getrandom_header = {
 int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
 {
 	struct tpm2_cmd cmd;
-	u32 recd;
+	u32 recd, rlength;
 	u32 num_bytes;
 	int err;
 	int total = 0;
@@ -373,13 +377,19 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
 		cmd.header.in = tpm2_getrandom_header;
 		cmd.params.getrandom_in.size = cpu_to_be16(num_bytes);
 
-		err = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0,
-				       "attempting get random");
+		err = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
+				       offsetof(struct tpm2_get_random_out,
+						buffer),
+				       0, "attempting get random");
 		if (err)
 			break;
 
 		recd = min_t(u32, be16_to_cpu(cmd.params.getrandom_out.size),
 			     num_bytes);
+		rlength = be32_to_cpu(cmd.header.out.length);
+		if (rlength < offsetof(struct tpm2_get_random_out, buffer) +
+			      recd)
+			return -EFAULT;
 		memcpy(dest, cmd.params.getrandom_out.buffer, recd);
 
 		dest += recd;
@@ -394,6 +404,9 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
 	(sizeof(struct tpm_input_header) + \
 	 sizeof(struct tpm2_get_tpm_pt_in))
 
+#define TPM2_GET_TPM_PT_OUT_BODY_SIZE \
+	 sizeof(struct tpm2_get_tpm_pt_out)
+
 static const struct tpm_input_header tpm2_get_tpm_pt_header = {
 	.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
 	.length = cpu_to_be32(TPM2_GET_TPM_PT_IN_SIZE),
@@ -445,7 +458,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 {
 	unsigned int blob_len;
 	struct tpm_buf buf;
-	u32 hash;
+	u32 hash, rlength;
 	int i;
 	int rc;
 
@@ -510,7 +523,8 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		goto out;
 	}
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 0, "sealing data");
+	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 4, 0,
+			      "sealing data");
 	if (rc)
 		goto out;
 
@@ -519,6 +533,11 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		rc = -E2BIG;
 		goto out;
 	}
+	rlength = be32_to_cpu(((struct tpm2_cmd *)&buf)->header.out.length);
+	if (rlength < TPM_HEADER_SIZE + 4 + blob_len) {
+		rc = -EFAULT;
+		goto out;
+	}
 
 	memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len);
 	payload->blob_len = blob_len;
@@ -588,7 +607,8 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 		goto out;
 	}
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, flags, "loading blob");
+	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 4, flags,
+			      "loading blob");
 	if (!rc)
 		*blob_handle = be32_to_cpup(
 			(__be32 *) &buf.data[TPM_HEADER_SIZE]);
@@ -626,7 +646,7 @@ static void tpm2_flush_context_cmd(struct tpm_chip *chip, u32 handle,
 
 	tpm_buf_append_u32(&buf, handle);
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, flags,
+	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 0, flags,
 			      "flushing context");
 	if (rc)
 		dev_warn(&chip->dev, "0x%08x was not flushed, rc=%d\n", handle,
@@ -657,6 +677,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 	u16 data_len;
 	u8 *data;
 	int rc;
+	u32 rlength;
 
 	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
 	if (rc)
@@ -671,13 +692,21 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 			     options->blobauth /* hmac */,
 			     TPM_DIGEST_SIZE);
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, flags, "unsealing");
+	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 6, flags,
+			      "unsealing");
 	if (rc > 0)
 		rc = -EPERM;
 
 	if (!rc) {
 		data_len = be16_to_cpup(
 			(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
+
+		rlength = be32_to_cpu(((struct tpm2_cmd *)&buf)
+					->header.out.length);
+		if (rlength < TPM_HEADER_SIZE + 6 + data_len) {
+			rc = -EFAULT;
+			goto out;
+		}
 		data = &buf.data[TPM_HEADER_SIZE + 6];
 
 		memcpy(payload->key, data, data_len - 1);
@@ -685,6 +714,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 		payload->migratable = data[data_len - 1];
 	}
 
+out:
 	tpm_buf_destroy(&buf);
 	return rc;
 }
@@ -739,7 +769,8 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
 	cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(property_id);
 	cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
 
-	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, desc);
+	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
+			      TPM2_GET_TPM_PT_OUT_BODY_SIZE, 0, desc);
 	if (!rc)
 		*value = be32_to_cpu(cmd.params.get_tpm_pt_out.value);
 
@@ -773,7 +804,7 @@ static int tpm2_startup(struct tpm_chip *chip, u16 startup_type)
 	cmd.header.in = tpm2_startup_header;
 
 	cmd.params.startup_in.startup_type = cpu_to_be16(startup_type);
-	return tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0,
+	return tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0,
 				"attempting to start the TPM");
 }
 
@@ -802,7 +833,8 @@ void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
 	cmd.header.in = tpm2_shutdown_header;
 	cmd.params.startup_in.startup_type = cpu_to_be16(shutdown_type);
 
-	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, "stopping the TPM");
+	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0,
+			      "stopping the TPM");
 
 	/* In places where shutdown command is sent there's no much we can do
 	 * except print the error code on a system failure.
@@ -865,7 +897,7 @@ static int tpm2_start_selftest(struct tpm_chip *chip, bool full)
 	cmd.header.in = tpm2_selftest_header;
 	cmd.params.selftest_in.full_test = full;
 
-	rc = tpm_transmit_cmd(chip, &cmd, TPM2_SELF_TEST_IN_SIZE, 0,
+	rc = tpm_transmit_cmd(chip, &cmd, TPM2_SELF_TEST_IN_SIZE, 0, 0,
 			      "continue selftest");
 
 	/* At least some prototype chips seem to give RC_TESTING error
@@ -916,7 +948,7 @@ static int tpm2_do_selftest(struct tpm_chip *chip)
 		cmd.params.pcrread_in.pcr_select[1] = 0x00;
 		cmd.params.pcrread_in.pcr_select[2] = 0x00;
 
-		rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, NULL);
+		rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0, NULL);
 		if (rc < 0)
 			break;
 
@@ -949,7 +981,7 @@ int tpm2_probe(struct tpm_chip *chip)
 	cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(0x100);
 	cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
 
-	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),  0, NULL);
+	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0, NULL);
 	if (rc <  0)
 		return rc;