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ima-evm-utils: use a common bank variable for TPM 1.2 and TPM 2.0

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Extend read_tpm_banks() to support TPM 1.2, by reading TPM 1.2 SHA1 PCRs
into the first bank and mark the other banks as disabled.

Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
This commit is contained in:
Mimi Zohar 2020-02-20 06:12:45 -05:00
parent acf2ac7559
commit 040c693b8b
1 changed files with 30 additions and 7 deletions
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35
src/evmctl.c
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@ -1399,7 +1399,7 @@ static int tpm_pcr_read(int idx, uint8_t *pcr, int len)
char *p, pcr_str[7], buf[70]; /* length of the TPM string */ char *p, pcr_str[7], buf[70]; /* length of the TPM string */
int result = -1; int result = -1;
sprintf(pcr_str, "PCR-%d", idx); sprintf(pcr_str, "PCR-%2.2d", idx);
fp = fopen(pcrs, "r"); fp = fopen(pcrs, "r");
if (!fp) if (!fp)
@ -1844,8 +1844,26 @@ static void extend_tpm_banks(struct template_entry *entry, int num_banks,
#endif #endif
} }
/* Read TPM 1.2 PCRs */
static int read_tpm_pcrs(int num_banks, struct tpm_bank_info *tpm_banks)
{
int i;
for (i = 0; i < NUM_PCRS; i++) {
if (tpm_pcr_read(i, tpm_banks[0].pcr[i], SHA_DIGEST_LENGTH)) {
log_debug("Failed to read TPM 1.2 PCRs.\n");
return -1;
}
}
tpm_banks[0].supported = 1;
for (i = 1; i < num_banks; i++)
tpm_banks[i].supported = 0;
return 0;
}
/* /*
* Attempt to read TPM PCRs from the multiple TPM 2.0 banks. * Attempt to read TPM PCRs from either TPM 1.2 or multiple TPM 2.0 banks.
* *
* On success reading from any TPM bank, return 0. * On success reading from any TPM bank, return 0.
*/ */
@ -1856,12 +1874,17 @@ static int read_tpm_banks(int num_banks, struct tpm_bank_info *bank)
int i, j; int i, j;
int err; int err;
/* First try reading PCRs from exported TPM 1.2 securityfs file */
if (read_tpm_pcrs(num_banks, bank) == 0)
return 0;
/* Any userspace applications available for reading TPM 2.0 PCRs? */ /* Any userspace applications available for reading TPM 2.0 PCRs? */
if (!tpm2_pcrread) { if (!tpm2_pcrread) {
log_info("Failed to read TPM 2.0 PCRs\n"); log_debug("Failed to read TPM 2.0 PCRs\n");
return 1; return 1;
} }
/* Read PCRs from multiple TPM 2.0 banks */
for (i = 0; i < num_banks; i++) { for (i = 0; i < num_banks; i++) {
err = 0; err = 0;
for (j = 0; j < NUM_PCRS && !err; j++) { for (j = 0; j < NUM_PCRS && !err; j++) {
@ -1869,7 +1892,7 @@ static int read_tpm_banks(int num_banks, struct tpm_bank_info *bank)
bank[i].pcr[j], bank[i].digest_size, bank[i].pcr[j], bank[i].digest_size,
&errmsg); &errmsg);
if (err) { if (err) {
log_info("Failed to read %s PCRs: (%s)\n", log_debug("Failed to read %s PCRs: (%s)\n",
bank[i].algo_name, errmsg); bank[i].algo_name, errmsg);
free(errmsg); free(errmsg);
bank[i].supported = 0; bank[i].supported = 0;
@ -1991,8 +2014,8 @@ static int ima_measurement(const char *file)
if (!verify_failed) if (!verify_failed)
err = 0; err = 0;
else if (read_tpm_banks(num_banks, tpm_banks) != 0) if (read_tpm_banks(num_banks, tpm_banks) != 0)
log_info("Failed to read TPM 2.0 PCRs\n"); log_info("Failed to read any TPM PCRs\n");
else else
err = compare_tpm_banks(num_banks, pseudo_banks, tpm_banks); err = compare_tpm_banks(num_banks, pseudo_banks, tpm_banks);