dh/ima-evm-utils-mirror
1
0
Fork 0
mirror of https://git.code.sf.net/p/linux-ima/ima-evm-utils synced 2025-04-27 22:32:31 +02:00
Code Releases Activity

ima-evm-utils: read the TPM 1.2 binary_bios_measurements

Browse Source 
Instead of just calculating the "boot_aggregate" based on the current
TPM PCRs, the original LTP and standalone ima_boot_aggregate test walked
the TPM 1.2 event log, calculating the PCRs.

If the TPM 1.2 event log is provided as an option on the "evmctl
ima_boot_aggregate" command, read the event log, calculate the sha1
PCRs, and calculate the "boot_aggregate" based on these PCRs.

The code for walking the IMA measurement list is based on the LTP and
standalone ima_boot_aggregate tests.  Similar support for reading the
TPM 2.0 event log to calculate the PCRs requires the TPM 2.0 event log
to be exported or a TSS to read the event log.  Parsing the TPM 2.0
event log is not supported here.

Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
This commit is contained in:
Mimi Zohar 2020-07-06 07:18:02 -04:00
parent 81aa698c70
commit f49e982627
1 changed files with 87 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
src/evmctl.c
View File

@ -1963,6 +1963,67 @@ static int cmd_ima_measurement(struct command *cmd)
return ima_measurement(file);
}
#define MAX_EVENT_DATA_SIZE 200000
static int read_binary_bios_measurements(char *file, struct tpm_bank_info *bank)
{
struct {
struct {
uint32_t pcr;
int type;
unsigned char digest[SHA_DIGEST_LENGTH];
uint32_t len;
} header;
unsigned char data[MAX_EVENT_DATA_SIZE];
} event;
FILE *fp;
SHA_CTX c;
int err = 0;
int i;
fp = fopen(file, "r");
if (!fp) {
log_errno("Failed to open TPM 1.2 event log.\n");
return 1;
}
if (imaevm_params.verbose > LOG_INFO)
log_info("Reading the TPM 1.2 event log %s.\n", file);
/* Extend the pseudo TPM PCRs with the event digest */
while (fread(&event, sizeof(event.header), 1, fp)) {
if (imaevm_params.verbose > LOG_INFO) {
log_info("%02u ", event.header.pcr);
log_dump(event.header.digest, SHA_DIGEST_LENGTH);
}
if (event.header.pcr > NUM_PCRS) {
log_err("Invalid PCR %d.\n", event.header.pcr);
err = 1;
break;
}
SHA1_Init(&c);
SHA1_Update(&c, bank->pcr[event.header.pcr], 20);
SHA1_Update(&c, event.header.digest, 20);
SHA1_Final(bank->pcr[event.header.pcr], &c);
if (event.header.len > MAX_EVENT_DATA_SIZE) {
log_err("Event data event too long.\n");
err = 1;
break;
}
fread(event.data, event.header.len, 1, fp);
}
fclose(fp);
if (imaevm_params.verbose <= LOG_INFO)
return err;
for (i = 0; i < NUM_PCRS; i++) {
log_info("PCR-%2.2x ", i);
log_dump(bank->pcr[i], SHA_DIGEST_LENGTH);
}
return err;
}
static void calc_bootaggr(struct tpm_bank_info *bank)
{
EVP_MD_CTX *pctx;
@ -2056,13 +2117,34 @@ static int cmd_ima_bootaggr(struct command *cmd)
char *bootaggr;
int num_banks = 0;
int offset = 0;
int err = 0;
int i;
tpm_banks = init_tpm_banks(&num_banks);
char *file = g_argv[optind++];
if (read_tpm_banks(num_banks, tpm_banks) != 0) {
log_info("Failed to read any TPM PCRs\n");
return -1;
/*
* Instead of just reading the TPM 1.2 PCRs, walk the exported
* TPM 1.2 SHA1 event log, calculating the PCRs.
*/
if (file) {
tpm_banks = init_tpm_banks(&num_banks);
/* TPM 1.2 only supports SHA1.*/
for (i = 1; i < num_banks; i++)
tpm_banks[i].supported = 0;
err = read_binary_bios_measurements(file, tpm_banks);
if (err) {
log_info("Failed reading the TPM 1.2 event log %s.\n",
file);
return -1;
}
} else {
tpm_banks = init_tpm_banks(&num_banks);
if (read_tpm_banks(num_banks, tpm_banks) != 0) {
log_info("Failed to read any TPM PCRs\n");
return -1;
}
}
/*
@ -2211,7 +2293,7 @@ struct command cmds[] = {
{"ima_setxattr", cmd_setxattr_ima, 0, "[--sigfile file]", "Set IMA signature from sigfile\n"},
{"ima_hash", cmd_hash_ima, 0, "file", "Make file content hash.\n"},
{"ima_measurement", cmd_ima_measurement, 0, "[--validate] [--verify] file", "Verify measurement list (experimental).\n"},
{"ima_boot_aggregate", cmd_ima_bootaggr, 0, "", "Calculate per TPM bank boot_aggregate digests\n"},
{"ima_boot_aggregate", cmd_ima_bootaggr, 0, "[file]", "Calculate per TPM bank boot_aggregate digests\n"},
{"ima_fix", cmd_ima_fix, 0, "[-t fdsxm] path", "Recursively fix IMA/EVM xattrs in fix mode.\n"},
{"ima_clear", cmd_ima_clear, 0, "[-t fdsxm] path", "Recursively remove IMA/EVM xattrs.\n"},
{"sign_hash", cmd_sign_hash, 0, "[--key key] [--pass [password]", "Sign hashes from shaXsum output.\n"},