PolicySecret sometimes fails with 0x98e

[YaHosoda]

Hi At first, I create several keys. 1 CreatePrimary with EK parameters. 2 Create(MK) under EK, policy Session. 3 Create(SK) under MK, HMAC Session.

Then, 4 Load SK, Hamdle is loadedSK 5 StartAuthSession with HMAC, the handle is Hsession 6 StartAuthSession with Policy, the handle is Psession 7 Compute HMAC with Hsession 8 PolicySecret(, Psession, HMAC ,...)

PolicySecret somtimes fails with 0x98e (Auth Fail)

IF I Do Create(SK) without HMAC Session of No.3. or IF I run the whole sequence, and re-run, without restarting the resource manager

Any suggestions?

[flihp]

This is a pretty complicated scenario. Can you link to your code?

[wcarthur1]

Even better, can you provide a debug trace dump that gives all the command and response byte streams to/from the TPM and the debug prints related to HMAC and session key calculations?

Will Arthur

From: Philip Tricca [mailto:notifications@github.com] Sent: Wednesday, June 14, 2017 12:15 PM To: 01org/TPM2.0-TSS TPM2.0-TSS@noreply.github.com Cc: Subscribed subscribed@noreply.github.com Subject: Re: [01org/TPM2.0-TSS] PolicySecret sometimes fails with 0x98e (#425)

This is a pretty complicated scenario. Can you link to your code?

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[YaHosoda]

Thank you for your responses. I am sorry to say that I cannot directly link my source here. But, I just identified two problems.

1 If I do not flush the at the end of each policy session , instead I try to flush them at the end of my program like this; Tss2_Sys_GetCapability (sysContext, 0, TPM_CAP_HANDLES, LOADED_SESSION_FIRST, 20, &moreData, &capabilityData, 0); CheckPassed (rval); printf ("Loaded session handles: %d\n", capabilityData.data.handles.count); for (i = 0; i < capabilityData.data.handles.count; i++) { DebugPrintf (NO_PREFIX, "0x%8x, \n", capabilityData.data.handles.handle[i]); rval = Tss2_Sys_FlushContext (sysContext, capabilityData.data.handles.handle[i]); CheckPassed (rval); } Next, I re-run the program, I encounter the 0x98e problem after PolicySecret with HMAC.

2 I start a HMAC sessions, call several TSS APIs without using this session handle, then I flush this session and continue my program, I encounter the 0x98e next time I call PolicySecret with HMAC.

Any advice would be appreciated

[flihp]

Decoding that response code is usually the first step. We have a tool over at the tpm2.0-tools project for doing this (tpm2_rc_decode). We could really use an strerror like function / library to allow folks to do this programmatically.

[wcarthur1]

You need to enable tracing with debug messages and the HMAC calculation messages turned on.

That’s the only way you’re ever going to be able to debug this.

From: YaHosoda [mailto:notifications@github.com] Sent: Thursday, June 15, 2017 11:08 AM To: 01org/TPM2.0-TSS TPM2.0-TSS@noreply.github.com Cc: wcarthur1 warthur@sigovs.com; Comment comment@noreply.github.com Subject: Re: [01org/TPM2.0-TSS] PolicySecret sometimes fails with 0x98e (#425)

Thank you for your responses. I am sorry to say that I cannot directly link my source here. But, I just identified two problems.

1 If I do not flush the at the end of each policy session , instead I try to flush them at the end of my program like this; Tss2_Sys_GetCapability (sysContext, 0, TPM_CAP_HANDLES, LOADED_SESSION_FIRST, 20, &moreData, &capabilityData, 0); CheckPassed (rval); printf ("Loaded session handles: %d\n", capabilityData.data.handles.count); for (i = 0; i < capabilityData.data.handles.count; i++) { DebugPrintf (NO_PREFIX, "0x%8x, \n", capabilityData.data.handles.handle[i]); rval = Tss2_Sys_FlushContext (sysContext, capabilityData.data.handles.handle[i]); CheckPassed (rval); } Next, I re-run the program, I encounter the 0x98e problem after PolicySecret with HMAC.

2 I start a HMAC sessions, call several TSS APIs without using this session handle, then I flush this session and continue my program, I encounter the 0x98e next time I call PolicySecret with HMAC.

Any advice would be appreciated

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[YaHosoda]

Thank you for your device. I set the DEBUG flag in TpmCalcPHash.c SessionHmac.c and re-compile. Below is the excerpt from the program and the execution log. Still, I can't find problems.

Source //loadedSha1KeyHandle_SK is a handle of a loaded signning key //nvAuth is the authValue of that key rval = AddEntity (loadedSha1KeyHandle_SK, &nvAuth); //nvSession_P is a policy session structure rval =
Tss2_Sys_PolicySecret_Prepare (sysContext, loadedSha1KeyHandle_SK, nvSession_P->sessionHandle, 0, 0, 0, 0); CheckPassed (rval); //nvSession is a HMAC session structure sessionData.sessionHandle = nvSession->sessionHandle; sessionData.hmac.t.size = 0; sessionData.nonce.t.size = 1; sessionData.nonce.t.buffer[0] = 0xa5; ((UINT32 ) (&sessionAttributes)) = 0; sessionData.sessionAttributes = sessionAttributes; sessionData.sessionAttributes.continueSession = 1;

// Roll nonces for command RollNonces (nvSession, &sessionData.nonce);

// Complete command authorization area, by computing // HMAC and setting it in sessionsData. rval = ComputeCommandHmacs (sysContext, loadedSha1KeyHandle_SK, nvSession_P->sessionHandle, &sessionsData, TPM_RC_FAILURE); CheckPassed (rval); rval =
Tss2_Sys_PolicySecret (sysContext, loadedSha1KeyHandle_SK, nvSession_P->sessionHandle, &sessionsData, 0, 0, 0, 0, 0, 0, &sessionsDataOut); CheckPassed (rval); RollNonces (nvSession, &sessionDataOut.nonce);

Good (First time) In GetSessionStruct

NAME1 = 00 0b ad a4 97 a0 ae 29 d1 52 73 3b c5 6c 9c 69 8d e0 80 61 d2 3a 1d 06 d0 57 76 82 ab 2c a9 53 6d 30

NAME2 = 03 00 00 01

PHASH input bytes= 00 00 01 51 00 0b ad a4 97 a0 ae 29 d1 52 73 3b c5 6c 9c 69 8d e0 80 61 d2 3a 1d 06 d0 57 76 82 ab 2c a9 53 6d 30 03 00 00 01 00 00 00 00 00 00 00 00 00 00

PHASH = 26 ed 16 11 dd 5b f0 62 97 f5 88 b5 13 aa de 6d e5 96 12 4d 6e 2b 3e 44 4e 62 b9 c3 aa 08 f5 c6

hmacKey = 4e 56 5f 50 61 73 73 77 6f 72 64 5f 6f 72 67 69 6e 61 6c 31 32 33 34 35 36 37 38 39 30 61 62 63

bufferlist[0]: 26 ed 16 11 dd 5b f0 62 97 f5 88 b5 13 aa de 6d e5 96 12 4d 6e 2b 3e 44 4e 62 b9 c3 aa 08 f5 c6

bufferlist[1]: a5

bufferlist[2]: 72 ac c5 6a b0 fe 81 20 d4 9f fd b4 94 e2 22 7c e4 d8 95 42

bufferlist[3]:

bufferlist[5]: 01 passing case: PASSED!

Second Time (Error) aIn GetSessionStruct

NAME1 = 00 0b b9 d6 a1 85 47 79 ab 83 46 72 66 cf 94 67 d2 cd 39 97 5b 02 63 88 9d 26 b1 a7 96 d2 53 5c 1f 8f

NAME2 = 03 00 00 00

PHASH input bytes= 00 00 01 51 00 0b b9 d6 a1 85 47 79 ab 83 46 72 66 cf 94 67 d2 cd 39 97 5b 02 63 88 9d 26 b1 a7 96 d2 53 5c 1f 8f 03 00 00 00 00 00 00 00 00 00 00 00 00 00

PHASH = 6a 60 75 02 4c 29 00 de 0d bb da 41 22 fd 3d ef f0 37 5f 14 6b b7 f8 7c 69 88 1f 52 fe ca a9 cd

hmacKey = 4e 56 5f 50 61 73 73 77 6f 72 64 5f 6f 72 67 69 6e 61 6c 31 32 33 34 35 36 37 38 39 30 61 62 63

bufferlist[0]: 6a 60 75 02 4c 29 00 de 0d bb da 41 22 fd 3d ef f0 37 5f 14 6b b7 f8 7c 69 88 1f 52 fe ca a9 cd

bufferlist[1]: a5

bufferlist[2]: aa 2d f1 c2 35 18 34 1b c5 60 3c 3a e7 27 5e cb 1e 99 3d aa

bufferlist[3]:

bufferlist[4]:

bufferlist[5]: 01 passing case: PASSED!

    passing case:   FAILED!  TPM Error: 0x98e