From: Mimi Zohar <zohar@linux.ibm.com>
To: linux-integrity@vger.kernel.org
Cc: Roberto Sassu <roberto.sassu@huawei.com>,
Vitaly Chikunov <vt@altlinux.org>,
Patrick Uiterwijk <puiterwi@redhat.com>,
Petr Vorel <pvorel@suse.cz>, Mimi Zohar <zohar@linux.ibm.com>
Subject: [RFC PATCH 5/8] ima-evm-utils: read the PCRs for the requested TPM banks
Date: Fri, 21 Feb 2020 13:38:55 -0500 [thread overview]
Message-ID: <1582310338-1562-6-git-send-email-zohar@linux.ibm.com> (raw)
In-Reply-To: <1582310338-1562-1-git-send-email-zohar@linux.ibm.com>
Read and store the PCRs for the requested banks to compare with the
re-calculated PCR values.
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
src/evmctl.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 50 insertions(+)
diff --git a/src/evmctl.c b/src/evmctl.c
index 1eeab1d8268b..3e512cf4e3d2 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -1423,6 +1423,7 @@ static int tpm_pcr_read(int idx, uint8_t *pcr, int len)
}
#ifdef HAVE_TSSPCRREAD
+static int tpm2_pcrread = 1;
static int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,
int len, char **errmsg)
{
@@ -1464,6 +1465,13 @@ static int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,
return ret;
}
+#else
+static int tpm2_pcrread = 0;
+static int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,
+ int len, char **errmsg)
+{
+ return -1;
+}
#endif
#define TCG_EVENT_NAME_LEN_MAX 255
@@ -1804,9 +1812,47 @@ static void extend_tpm_banks(struct template_entry *entry, int num_banks,
#endif
}
+/*
+ * Attempt to read TPM PCRs from the multiple TPM 2.0 banks.
+ *
+ * On success reading from any TPM bank, return 0.
+ */
+static int read_tpm_banks(int num_banks, struct tpm_bank_info *bank)
+{
+ int tpm_enabled = 0;
+ char *errmsg = NULL;
+ int i, j;
+ int err;
+
+ /* Any userspace applications available for reading TPM 2.0 PCRs? */
+ if (!tpm2_pcrread) {
+ log_info("Failed to read TPM 2.0 PCRs\n");
+ return 1;
+ }
+
+ for (i = 0; i < num_banks; i++) {
+ err = 0;
+ for (j = 0; j < NUM_PCRS && !err; j++) {
+ err = tpm2_pcr_read(bank[i].algo_name, j,
+ bank[i].pcr[j], bank[i].digest_size,
+ &errmsg);
+ if (err) {
+ log_info("Failed to read %s PCRs: (%s)\n",
+ bank[i].algo_name, errmsg);
+ free(errmsg);
+ bank[i].supported = 0;
+ }
+ }
+ if (bank[i].supported)
+ tpm_enabled = 1;
+ }
+ return tpm_enabled ? 0 : 1;
+}
+
static int ima_measurement(const char *file)
{
struct tpm_bank_info *pseudo_banks;
+ struct tpm_bank_info *tpm_banks;
int num_banks = 0;
uint8_t pcr[NUM_PCRS][SHA_DIGEST_LENGTH] = {{0}};
@@ -1825,6 +1871,7 @@ static int ima_measurement(const char *file)
log_debug_dump(pcr, sizeof(pcr));
pseudo_banks = init_tpm_banks(&num_banks);
+ tpm_banks = init_tpm_banks(&num_banks);
fp = fopen(file, "rb");
if (!fp) {
@@ -1912,6 +1959,9 @@ static int ima_measurement(const char *file)
if (!verify_failed)
err = 0;
+ else
+ read_tpm_banks(num_banks, tpm_banks);
+
out:
fclose(fp);
return err;
--
2.7.5
next prev parent reply other threads:[~2020-02-21 18:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 18:38 [RFC PATCH 0/8] ima-evm-utils: calculate per TPM bank template digest Mimi Zohar
2020-02-21 18:38 ` [RFC PATCH 1/8] ima-evm-utils: treat unallocated banks as an error Mimi Zohar
2020-02-21 18:38 ` [RFC PATCH 2/8] ima-evm-utils: increase the size of "zero" and "fox" variables Mimi Zohar
2020-02-21 18:38 ` [RFC PATCH 3/8] ima-evm-utils: calculate the digests for multiple TPM banks Mimi Zohar
2020-02-21 18:38 ` [RFC PATCH 4/8] ima-evm-utils: add support in tpm2_read_pcrs to read different " Mimi Zohar
2020-02-21 18:38 ` Mimi Zohar [this message]
2020-02-21 18:38 ` [RFC PATCH 6/8] ima-evm-utils: compare re-calculated PCRs with the TPM values Mimi Zohar
2020-02-21 18:38 ` [RFC PATCH 7/8] ima-evm-utils: use a common bank variable for TPM 1.2 and TPM 2.0 Mimi Zohar
2020-02-21 18:38 ` [RFC PATCH 8/8] ima-evm-utils: remove TPM 1.2 specific code Mimi Zohar
2020-02-22 0:11 ` [RFC PATCH 0/8] ima-evm-utils: calculate per TPM bank template digest Lakshmi Ramasubramanian
2020-02-23 1:12 ` Mimi Zohar
2020-02-24 16:23 ` Lakshmi Ramasubramanian
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