Tspi_TPM_GetCapability(3)

✨ Tspi_TPM_GetCapability ✨

okay bestie, welcome to the TCG Software Stack Developer's Reference 💖 this one's a manual page from the Tspi_TPM_GetCapability(3) family, living in the Library Functions Manual, and it's literally your little gossip line to the TPM. let's get into it 🫶

🌸 NAME 🌸

Tspi_TPM_GetCapability — get information on the capabilities of the TPM 👑

🎀 SYNOPSIS 🎀

#include <tss/platform.h>
#include <tss/tcpa_defines.h>
#include <tss/tcpa_typedef.h>
#include <tss/tcpa_struct.h>
#include <tss/tss_typedef.h>
#include <tss/tss_structs.h>
#include <tss/tspi.h>

TSS_RESULT Tspi_TPM_GetCapability(TSS_HTPM hTPM,              TSS_FLAG capArea,
                                  UINT32   ulSubCapLength,    BYTE*    rgbSubCap,
                                  UINT32*  pulRespDataLength, BYTE**   prgbRespData);

🦋 DESCRIPTION 🦋

so Tspi_TPM_GetCapability gets information on various capabilities of the TPM. that's it, that's the vibe ✨ you can use this command to learn how many PCRs the TPM supports, etc. it's giving "asking the TPM to spill the tea about itself" 💅

💜 PARAMETERS 💜

hTPM

the hTPM parameter is used to specify the handle of the TPM object. it's the lil ID card you hand over so the TPM knows who it's talking to 🪪

capArea

the capArea parameter is the flag indicating the attribute to query. possible values are:

ulSubCapLength

the ulSubCapLength parameter is the length in bytes of the rgbSubCap parameter. yes it's just the size tag, iconic behavior 📏

rgbSubCap

the rgbSubCap parameter is the data indicating the attribute to query. possible values are:

pulRespDataLength

the pulRespDataLength parameter is the length in bytes of the prgbRespData parameter. it tells you how much data came back 🎀

prgbRespData

the prgbRespData parameter receives a pointer to the actual data of the specified attribute. the real payload, the main character moment 👑

⭐ NOTES ⭐

the following Capability Areas and Sub-Capability Areas are supported by 1.1 TSS's:

• TSS_TPMCAP_ORD — query whether an ordinal is supported by the TPM.
  • subCaps: TPM_ORD_* (see tcpa_literals.h)
• TSS_TPMCAP_FLAG — query for the volatile and non-volatile flags inside the TPM. (Must be owner authorized 🔐). In this case, the 2 UINT32 values will be returned concatenated together in prgbRespData.
  • subCaps: ignored.
• TSS_TPMCAP_ALG — query whether an algorithm is supported by the TPM.
  • subCaps:
    • TSS_ALG_RSA
    • TSS_ALG_DES
    • TSS_ALG_3DES
    • TSS_ALG_SHA
    • TSS_ALG_HMAC
    • TSS_ALG_AES
• TSS_TPMCAP_PROPERTY — query a property of the TPM.
  • subCaps:
    • TSS_TPMCAP_PROP_PCR
    • TSS_TPMCAP_PROP_DIR
    • TSS_TPMCAP_PROP_MANUFACTURER
    • TSS_TPMCAP_PROP_SLOTS
• TSS_TPMCAP_VERSION — get the TSS_VERSION structure tha identifies the TPM.
  • subCaps: ignored.

ngl bestie, the typo in "tha identifies the TPM" is a direct quote from the original — we keep it exactly as-is, no editing the ancestors 📝

💀 RETURN CODES 💀

Tspi_TPM_GetCapability returns TSS_SUCCESS on success, otherwise one of the following values is returned:

• TSS_E_INVALID_HANDLE — hTPM is not a valid handle. not it 😭
• TSS_E_INTERNAL_ERROR — An internal SW error has been detected. the software tripped, no cap 💀
• TSS_E_BAD_PARAMETER — One or more parameters is bad. bad parameters? in this economy? 🙈

🌈 CONFORMING TO 🌈

Tspi_TPM_GetCapability conforms to the Trusted Computing Group Software Specification version 1.1 Golden — yes, it's certified, it's official, it ate 💅

🔥 SEE ALSO 🔥

• Tspi_TPM_GetCapabilitySigned(3)
• Tspi_TPM_GetEvent(3)

and that's the whole page, bestie 🎀 this one's from TSS 1.1, dated 2004-05-25 — so yes she's an elder icon, but she still slays 💖✨🦋 go query some capabilities, you got this 🫶👑