mirror of
https://github.com/stefanberger/libtpms
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a8622792c0
To avoid timeouts on short-running commands, such as TPM2_PCR_Extend, avoid triggering the writing of the permanent state of the TPM 2 if only the clock was updated. So the clock by itself will not cause the permanent state to be written out anymore but there have to be other reasons as well. The state will still be written out upon a TPM2_Shutdown, which is supposed to be the last command to be sent to the TPM when shutting down the VM/vTPM. Also, the permanent state will still carry the latest clock value if it is retrieved via control channel for VM/VTPM suspend. The case that may be affected, but is of lesser importance, is the one where swtpm's volatile state is written to storage using 'swtpm_ioctl -v' and then swtpm is terminated and restarted (similar to suspend/resume) and the permanent state file is read from storage but does not contain the latest clock value. In this case the go.clock will be updated when the first command after resume is executed. This fixes the swtpm issue https://github.com/stefanberger/swtpm/issues/597. Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> |
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| .github/ISSUE_TEMPLATE | ||
| debian | ||
| dist | ||
| include | ||
| m4 | ||
| man | ||
| src | ||
| tests | ||
| .gitignore | ||
| .travis.yml | ||
| autogen.sh | ||
| bootstrap.sh | ||
| CHANGES | ||
| configure.ac | ||
| CREDITS | ||
| DCO1.1.txt | ||
| INSTALL | ||
| libtpms.pc.in | ||
| LICENSE | ||
| Makefile.am | ||
| README | ||
What is libtpms?
----------------
Libtpms is a library that targets the integration of TPM functionality
into hypervisors, primarily into Qemu. Libtpms provides a very narrow
public API for this purpose so that integration is possible. Only the
minimum of necessary APIs are made publicly available.
It is assumed that the user of libtpms is familiar with the concepts
of the Trusted Platform Module (TPM). For the interaction with libtpms
it is necessary to know how to construct valid TPM commands and to
be able to parse their results. It is not within the scope of libtpms's
documentation to provide background on this. See the section on references
below.
What files does the libtpms package provide?
--------------------------------------------
The main libtpms package provides the following files:
/usr/lib64/libtpms.so.0
/usr/lib64/libtpms.so.0.5.1
/usr/share/doc/libtpms-0.5.1
/usr/share/doc/libtpms-0.5.1/CHANGES
/usr/share/doc/libtpms-0.5.1/LICENSE
/usr/share/doc/libtpms-0.5.1/README
Applications can link with -ltpms.
What files does the libtpms development package provide?
--------------------------------------------------------
The libtpms development package (libtpms-devel) provides the following
include files for applications to use:
tpm_error.h
tpm_library.h
tpm_memory.h
tpm_nvfilename.h
tpm_tis.h
tpm_types.h
These files contain the data structures, data types and API calls supported
by libtpms. It is recommended to not use any other API calls than those
provided in these include files.
All APIs are described in man pages. The man pages are part of the libtpms
development package as well:
TPMLIB_DecodeBlob
TPMLIB_GetTPMProperty
TPMLIB_GetVersion
TPMLIB_MainInit
TPMLIB_Process
TPMLIB_RegisterCallbacks
TPMLIB_Terminate
TPMLIB_VolatileAll_Store
TPM_Free
TPM_IO_Hash_Data
TPM_IO_Hash_End
TPM_IO_Hash_Start
TPM_IO_TpmEstablished_Get
TPM_Malloc
TPM_Realloc
How to contribute?
------------------
The mailing list for libtpms is libtpms@googlegroups.com.
For patch submissions, please use a Signed-off-by: <your email> to indicate
agreement to the DCO1.1.txt.
Fuzzing
-------
Initial fuzzing is possible with clang & libfuzzer.
You have to configure the project with --enable-fuzzer
(--enable-sanitizer can also help spot more issues). Then you can
build fuzz and run it with the testing corpus.
Fuzz testing is known to work with Fedora 28 or later. It requires that the
'clang' package is installed.
Ex:
$ ./configure --with-openssl --with-tpm2 --enable-sanitizers --enable-fuzzer \
CC=clang CXX=clang++
$ make && make -C tests fuzz
$ tests/run-fuzzer.sh
oss-fuzz builds with its own fuzzer flags, and set $LIB_FUZZING_ENGINE
to be linked with. The script run by oss-fuzz is tests/oss-fuzz.sh.
Maintainers
-----------
libtpms is currently being maintained by Stefan Berger <stefanb@us.ibm.com>.
References:
-----------
Documentation about the Trusted Platform Module (TPM) can be downloaded
from the Trusted Computing Group's website at
http://www.trustedcomputinggroup.org