TPM 2.0 banks may be extended either with a padded SHA1 hash or more
recently with a per TPM bank calculated hash. If the measurement list
is carried across kexec, the original kernel might extend the TPM
differently than the new kernel.
Support for verifying a mixed IMA measurement list is not supported. To
permit verifying just the SHA1 bank, specify "--verify-bank=sha1" on the
command line.
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
---
src/evmctl.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/src/evmctl.c b/src/evmctl.c
index f7ffe388ef4f..051c218cc8b5 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -125,6 +125,7 @@ static char *caps_str;
static char *ima_str;
static char *selinux_str;
static char *search_type;
+static char *verify_bank;
static int verify_list_sig;
static int recursive;
static int msize;
@@ -2011,6 +2012,16 @@ static int ima_measurement(const char *file)
pseudo_banks_mask = (1 << num_banks) - 1;
pseudo_padded_banks_mask = pseudo_banks_mask;
+ /* Instead of verifying all the banks, only verify a single bank */
+ for (c = 0; c < num_banks; c++) {
+ if (verify_bank
+ && strcmp(pseudo_padded_banks[c].algo_name, verify_bank)) {
+ pseudo_banks_mask ^= (1 << c);
+ pseudo_padded_banks_mask ^= (1 << c);
+ break;
+ }
+ }
+
while (fread(&entry.header, sizeof(entry.header), 1, fp)) {
entry_num++;
if (entry.header.name_len > TCG_EVENT_NAME_LEN_MAX) {
@@ -2537,7 +2548,7 @@ struct command cmds[] = {
{"ima_verify", cmd_verify_ima, 0, "file", "Verify IMA signature (for debugging).\n"},
{"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, "[--ignore-violations] [--verify-sig [--key key1, key2, ...]] [--pcrs [hash-algorithm,]file [--pcrs hash-algorithm,file] ...] file", "Verify measurement list (experimental).\n"},
+ {"ima_measurement", cmd_ima_measurement, 0, "[--ignore-violations] [--verify-sig [--key key1, key2, ...]] [--pcrs [hash-algorithm,]file [--pcrs hash-algorithm,file] ...] [--verify-bank hash-algorithm] file", "Verify measurement list (experimental).\n"},
{"ima_boot_aggregate", cmd_ima_bootaggr, 0, "[--pcrs hash-algorithm,file] [TPM 1.2 BIOS event log]", "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"},
@@ -2578,6 +2589,7 @@ static struct option opts[] = {
{"xattr-user", 0, 0, 140},
{"ignore-violations", 0, 0, 141},
{"pcrs", 1, 0, 142},
+ {"verify-bank", 2, 0, 143},
{}
};
@@ -2766,6 +2778,9 @@ int main(int argc, char *argv[])
}
pcrfile[npcrfile++] = optarg;
break;
+ case 143:
+ verify_bank = optarg;
+ break;
case '?':
exit(1);
break;
--
2.27.0
