tpm2: add salt to pin

Add a salt to the pin and store it in the TPM2 LUKS header for future
this. This adds entropy to user supplied pins and helps brute forcing
the passphrase on the key residing in the TPM or brute forcing bind key
encrypted sessions with low entropy passphrases.

Signed-off-by: malikabhi05 <abhishek.malik@intel.com>
Signed-off-by: William Roberts <william.c.roberts@intel.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/src/test/test-tpm2.c b/src/test/test-tpm2.c
index c5f3d41da9..04e08490b3 100644
--- a/src/test/test-tpm2.c
+++ b/src/test/test-tpm2.c
@@ -28,4 +28,45 @@ TEST(tpm2_parse_pcrs) {
         test_tpm2_parse_pcrs_one("foo", 0, -EINVAL);
 }
 
+TEST(tpm2_util_pbkdf2_hmac_sha256) {
+
+        /*
+         * The test vectors from RFC 6070 [1] are for dkLen of 20 as it's SHA1
+         * other RFCs I bumped into had various differing dkLen and iter counts,
+         * so this was generated using Python's hmacmodule.
+         *
+         * 1. https://www.rfc-editor.org/rfc/rfc6070.html#page-2
+         */
+        static const struct {
+                const uint8_t pass[256];
+                size_t passlen;
+                const uint8_t salt[256];
+                size_t saltlen;
+                uint8_t expected[SHA256_DIGEST_SIZE];
+        } test_vectors[] = {
+                { .pass={'f', 'o', 'o', 'p', 'a', 's', 's'},                                                                        .passlen=7,  .salt={'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5'}, .saltlen=16, .expected={0xCB, 0xEA, 0x27, 0x23, 0x9A, 0x65, 0x99, 0xF6, 0x8C, 0x26, 0x54, 0x80, 0x5C, 0x63, 0x61, 0xD2, 0x91, 0x0A, 0x60, 0x3F, 0xC2, 0xF5, 0xF0, 0xAB, 0x55, 0x8B, 0x46, 0x07, 0x60, 0x93, 0xAB, 0xCB} },
+                { .pass={'f', 'o', 'o', 'p', 'a', 's', 's'},                                                                        .passlen=7,  .salt={0x00, 'h', 'f', 's', 'd', 'j', 'h', 'f', 'd', 'j', 'h', 'j', 'd', 'f', 's'},     .saltlen=15, .expected={0x2B, 0xDF, 0x52, 0x29, 0x48, 0x3F, 0x98, 0x25, 0x01, 0x19, 0xB4, 0x42, 0xBC, 0xA7, 0x38, 0x5D, 0xCD, 0x08, 0xBD, 0xDC, 0x33, 0xBF, 0x32, 0x5E, 0x31, 0x87, 0x54, 0xFF, 0x2C, 0x23, 0x68, 0xFF} },
+                { .pass={'f', 'o', 'o', 'p', 'a', 's', 's'},                                                                        .passlen=7,  .salt={'m', 'y', 's', 'a', 0x00, 'l', 't'},                                             .saltlen=7,  .expected={0x7C, 0x24, 0xB4, 0x4D, 0x30, 0x11, 0x53, 0x24, 0x87, 0x56, 0x24, 0x10, 0xBA, 0x9F, 0xF2, 0x4E, 0xBB, 0xF5, 0x03, 0x56, 0x2B, 0xB1, 0xA1, 0x92, 0x8B, 0x5F, 0x32, 0x02, 0x23, 0x1F, 0x79, 0xE6} },
+                { .pass={'p', 'a', 's', 's', 'w', 'i', 't', 'h', 'n', 'u', 'l', 'l', 0x00, 'p', 'a', 's', 's', 'w', 'o', 'r', 'd'}, .passlen=21, .salt={'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5'}, .saltlen=16, .expected={0xE9, 0x53, 0xB7, 0x1D, 0xAB, 0xD1, 0xC1, 0xF3, 0xC4, 0x7F, 0x18, 0x96, 0xDD, 0xD7, 0x6B, 0xC6, 0x6A, 0xBD, 0xFB, 0x12, 0x7C, 0xF8, 0x68, 0xDC, 0x6E, 0xEF, 0x29, 0xCC, 0x1B, 0x30, 0x5B, 0x74} },
+                { .pass={'p', 'a', 's', 's', 'w', 'i', 't', 'h', 'n', 'u', 'l', 'l', 0x00, 'p', 'a', 's', 's', 'w', 'o', 'r', 'd'}, .passlen=21, .salt={0x00, 'h', 'f', 's', 'd', 'j', 'h', 'f', 'd', 'j', 'h', 'j', 'd', 'f', 's'},     .saltlen=15, .expected={0x51, 0xA3, 0x82, 0xA5, 0x2F, 0x48, 0x84, 0xB3, 0x02, 0x0D, 0xC2, 0x42, 0x9A, 0x8F, 0x86, 0xCC, 0x66, 0xFD, 0x65, 0x87, 0x89, 0x07, 0x2B, 0x07, 0x82, 0x42, 0xD6, 0x6D, 0x43, 0xB8, 0xFD, 0xCF} },
+                { .pass={'p', 'a', 's', 's', 'w', 'i', 't', 'h', 'n', 'u', 'l', 'l', 0x00, 'p', 'a', 's', 's', 'w', 'o', 'r', 'd'}, .passlen=21, .salt={'m', 'y', 's', 'a', 0x00, 'l', 't'},                                             .saltlen=7,  .expected={0xEC, 0xFB, 0x5D, 0x5F, 0xF6, 0xA6, 0xE0, 0x79, 0x50, 0x64, 0x36, 0x64, 0xA3, 0x9A, 0x5C, 0xF3, 0x7A, 0x87, 0x0B, 0x64, 0x51, 0x59, 0x75, 0x64, 0x8B, 0x78, 0x2B, 0x62, 0x8F, 0x68, 0xD9, 0xCC} },
+                { .pass={0x00, 'p', 'a', 's', 's'},                                                                                 .passlen=5,  .salt={'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5'}, .saltlen=16, .expected={0x8A, 0x9A, 0x47, 0x9A, 0x91, 0x22, 0x2F, 0x56, 0x29, 0x4F, 0x26, 0x00, 0xE7, 0xB3, 0xEB, 0x63, 0x6D, 0x51, 0xF2, 0x60, 0x17, 0x08, 0x20, 0x70, 0x82, 0x8F, 0xA3, 0xD7, 0xBE, 0x2B, 0xD5, 0x5D} },
+                { .pass={0x00, 'p', 'a', 's', 's'},                                                                                 .passlen=5,  .salt={0x00, 'h', 'f', 's', 'd', 'j', 'h', 'f', 'd', 'j', 'h', 'j', 'd', 'f', 's'},     .saltlen=15, .expected={0x72, 0x3A, 0xF5, 0xF7, 0xCD, 0x6C, 0x12, 0xDD, 0x53, 0x28, 0x46, 0x0C, 0x19, 0x0E, 0xF2, 0x91, 0xDE, 0xEA, 0xF9, 0x6F, 0x74, 0x32, 0x34, 0x3F, 0x84, 0xED, 0x8D, 0x2A, 0xDE, 0xC9, 0xC6, 0x34} },
+                { .pass={0x00, 'p', 'a', 's', 's'},                                                                                 .passlen=5,  .salt={'m', 'y', 's', 'a', 0x00, 'l', 't'},                                             .saltlen=7,  .expected={0xE3, 0x07, 0x12, 0xBE, 0xEE, 0xF5, 0x5D, 0x18, 0x72, 0xF4, 0xCF, 0xF1, 0x20, 0x6B, 0xD6, 0x66, 0xCD, 0x7C, 0xE7, 0x4F, 0xC2, 0x16, 0x70, 0x5B, 0x9B, 0x2F, 0x7D, 0xE2, 0x3B, 0x42, 0x3A, 0x1B} },
+        };
+
+        uint8_t res[SHA256_DIGEST_SIZE];
+        for(size_t i = 0; i < sizeof(test_vectors)/sizeof(test_vectors[0]); i++) {
+
+                int rc = tpm2_util_pbkdf2_hmac_sha256(
+                                test_vectors[i].pass,
+                                test_vectors[i].passlen,
+                                test_vectors[i].salt,
+                                test_vectors[i].saltlen,
+                                res);
+                assert_se(rc == 0);
+                assert_se(memcmp(test_vectors[i].expected, res, SHA256_DIGEST_SIZE) == 0);
+        }
+}
+
 DEFINE_TEST_MAIN(LOG_DEBUG);