[SeaBIOS] [RFC PATCH v1 7/9] tpm: Implement tpm2_extend

[Stefan Berger]

From: Stefan Berger

Implement the tpm2_extend function. We use it with only SHA1.

Signed-off-by: Stefan Berger 
---
 src/std/tcg.h | 17 +++++++++++++++++
 src/tcgbios.c | 34 ++++++++++++++++++++++++++++++++--
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/src/std/tcg.h b/src/std/tcg.h
index e0d6f30..d45c7f6 100644
--- a/src/std/tcg.h
+++ b/src/std/tcg.h
@@ -375,6 +375,8 @@ struct tpm_res_sha1complete {
 #define TPM2_RS_PW                  0x40000009
 #define TPM2_RH_PLATFORM            0x4000000c

+#define TPM2_ALG_SHA1               0x0004
+
 /* TPM 2 command tags */
 #define TPM2_ST_NO_SESSIONS         0x8001
 #define TPM2_ST_SESSIONS            0x8002
@@ -385,6 +387,7 @@ struct tpm_res_sha1complete {
 #define TPM2_CC_Startup             0x144
 #define TPM2_CC_StirRandom          0x146
 #define TPM2_CC_GetRandom           0x17b
+#define TPM2_CC_PCR_Extend          0x182

/* TPM 2 error codes */
 #define TPM2_RC_INITIALIZE          0x100
@@ -426,4 +429,18 @@ struct tpm2_req_hierarchychangeauth {
     struct tpm2b_20 newAuth;
 } PACKED;

+struct tpm2_digest_value {
+    u32 count; /* 1 entry only */
+    u16 hashalg; /* TPM2_ALG_SHA1 */
+    u8 sha1[SHA1_BUFSIZE];
+} PACKED;
+
+struct tpm2_req_extend {
+    struct tpm_req_header hdr;
+    u32 pcrindex;
+    u32 authblocksize;
+    struct tpm2_authblock authblock;
+    struct tpm2_digest_value digest;
+} PACKED;
+
 #endif // tcg.h
diff --git a/src/tcgbios.c b/src/tcgbios.c
index 4f5c5bb..627a374 100644
--- a/src/tcgbios.c
+++ b/src/tcgbios.c
@@ -361,6 +361,37 @@ tpm12_extend(u32 pcrindex, const u8 *digest)
     return 0;
 }

+static int tpm2_extend(u32 pcrindex, const u8 *digest)
+{
+    struct tpm2_req_extend tre = {
+        .hdr.tag     = cpu_to_be16(TPM2_ST_SESSIONS),
+        .hdr.totlen  = cpu_to_be32(sizeof(tre)),
+        .hdr.ordinal = cpu_to_be32(TPM2_CC_PCR_Extend),
+        .pcrindex    = cpu_to_be32(pcrindex),
+        .authblocksize = cpu_to_be32(sizeof(tre.authblock)),
+        .authblock = {
+            .handle = cpu_to_be32(TPM2_RS_PW),
+            .noncesize = cpu_to_be16(0),
+            .contsession = TPM2_YES,
+            .pwdsize = cpu_to_be16(0),
+        },
+        .digest = {
+            .count = cpu_to_be32(1),
+            .hashalg = cpu_to_be16(TPM2_ALG_SHA1),
+        },
+    };
+    memcpy(tre.digest.sha1, digest, sizeof(tre.digest.sha1));
+
+    struct tpm_rsp_header rsp;
+    u32 resp_length = sizeof(rsp);
+    int ret = tpmhw_transmit(0, &tre.hdr, &rsp, &resp_length,
+                             TPM_DURATION_TYPE_SHORT);
+    if (ret || resp_length != sizeof(rsp) || rsp.errcode)
+        return -1;
+
+    return 0;
+}
+
 static int
 tpm_extend(u32 pcrindex, const u8 *digest)
 {
@@ -371,8 +402,7 @@ tpm_extend(u32 pcrindex, const u8 *digest)
     case TPM_VERSION_1_2:
         return tpm12_extend(pcrindex, digest);
     case TPM_VERSION_2:
-        // FIXME: missing code
-        return -1;
+        return tpm2_extend(pcrindex, digest);
     }
     return -1;
 }