From: Roberto Sassu <roberto.sassu@huawei.com>
To: <jarkko.sakkinen@linux.intel.com>, <zohar@linux.ibm.com>,
<david.safford@ge.com>, <monty.wiseman@ge.com>
Cc: <linux-integrity@vger.kernel.org>,
<linux-security-module@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <silviu.vlasceanu@huawei.com>,
Roberto Sassu <roberto.sassu@huawei.com>,
<stable@vger.kernel.org>
Subject: [PATCH v5 6/7] tpm: ensure that the output of PCR read contains the correct digest size
Date: Wed, 14 Nov 2018 16:31:07 +0100 [thread overview]
Message-ID: <20181114153108.12907-7-roberto.sassu@huawei.com> (raw)
In-Reply-To: <20181114153108.12907-1-roberto.sassu@huawei.com>
This patch protects against data corruption that could happen in the bus,
by checking that that the digest size returned by the TPM during a PCR read
matches the size of the algorithm passed to tpm2_pcr_read().
This check is performed after information about the PCR banks has been
retrieved.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: stable@vger.kernel.org
---
drivers/char/tpm/tpm2-cmd.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index acaaab72ef2e..974465f04b78 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -179,15 +179,29 @@ struct tpm2_pcr_read_out {
int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digest_struct, u16 *digest_size_ptr)
{
+ int i;
int rc;
struct tpm_buf buf;
struct tpm2_pcr_read_out *out;
u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0};
u16 digest_size;
+ u16 expected_digest_size = 0;
if (pcr_idx >= TPM2_PLATFORM_PCR)
return -EINVAL;
+ if (!digest_size_ptr) {
+ for (i = 0; i < chip->nr_allocated_banks &&
+ chip->allocated_banks[i].alg_id != digest_struct->alg_id;
+ i++)
+ ;
+
+ if (i == chip->nr_allocated_banks)
+ return -EINVAL;
+
+ expected_digest_size = chip->allocated_banks[i].digest_size;
+ }
+
rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ);
if (rc)
return rc;
@@ -207,7 +221,8 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
digest_size = be16_to_cpu(out->digest_size);
- if (digest_size > sizeof(digest_struct->digest)) {
+ if (digest_size > sizeof(digest_struct->digest) ||
+ (!digest_size_ptr && digest_size != expected_digest_size)) {
rc = -EINVAL;
goto out;
}
--
2.17.1
next prev parent reply other threads:[~2018-11-14 15:36 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-14 15:31 [PATCH v5 0/7] tpm: retrieve digest size of unknown algorithms from TPM Roberto Sassu
2018-11-14 15:31 ` [PATCH v5 1/7] tpm: dynamically allocate the allocated_banks array Roberto Sassu
2018-11-16 13:36 ` Jarkko Sakkinen
2018-11-14 15:31 ` [PATCH v5 2/7] tpm: remove definition of TPM2_ACTIVE_PCR_BANKS Roberto Sassu
2018-11-16 13:38 ` Jarkko Sakkinen
2018-11-28 7:50 ` Roberto Sassu
2018-11-28 12:17 ` Roberto Sassu
2018-11-29 12:04 ` Roberto Sassu
2018-11-30 19:41 ` Jarkko Sakkinen
2018-11-30 19:45 ` Jarkko Sakkinen
2018-11-30 22:18 ` Jarkko Sakkinen
2018-12-03 9:59 ` Roberto Sassu
2018-12-03 17:31 ` Jarkko Sakkinen
2018-11-14 15:31 ` [PATCH v5 3/7] tpm: rename and export tpm2_digest and tpm2_algorithms Roberto Sassu
2018-11-14 15:31 ` [PATCH v5 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm Roberto Sassu
2018-11-16 13:41 ` Jarkko Sakkinen
2018-11-14 15:31 ` [PATCH v5 5/7] tpm: retrieve digest size of unknown algorithms with PCR read Roberto Sassu
2018-11-14 15:31 ` Roberto Sassu [this message]
2018-11-16 13:41 ` [PATCH v5 6/7] tpm: ensure that the output of PCR read contains the correct digest size Jarkko Sakkinen
2018-11-16 16:06 ` Roberto Sassu
2018-11-18 7:32 ` Jarkko Sakkinen
2018-11-19 8:14 ` Roberto Sassu
2018-11-19 14:33 ` Jarkko Sakkinen
2018-11-19 15:09 ` Roberto Sassu
2018-11-19 16:07 ` Jarkko Sakkinen
2018-11-28 8:40 ` Roberto Sassu
2018-11-28 19:19 ` Jarkko Sakkinen
2018-11-14 15:31 ` [PATCH v5 7/7] tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend() Roberto Sassu
2018-11-16 15:03 ` Jarkko Sakkinen
2018-11-16 15:55 ` Roberto Sassu
2018-11-18 7:27 ` Jarkko Sakkinen
2018-11-19 4:57 ` Mimi Zohar
2018-11-19 8:16 ` Roberto Sassu
2018-11-19 14:33 ` Mimi Zohar
2018-11-19 14:39 ` Jarkko Sakkinen
2018-11-18 7:29 ` Jarkko Sakkinen
2018-11-19 8:22 ` Roberto Sassu
2018-11-19 14:42 ` Jarkko Sakkinen
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