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Dmitrii Kuvaiskii
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Add swtpm example
Signed-off-by: Dmitrii Kuvaiskii <[email protected]>
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‎swtpm/Makefile‎

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ARCH_LIBDIR ?= /lib/$(shell $(CC) -dumpmachine)
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ifeq ($(DEBUG),1)
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GRAMINE_LOG_LEVEL = all
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else
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GRAMINE_LOG_LEVEL = error
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endif
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ifeq ($(SGX),1)
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GRAMINE_ENCRYPTION_KEY = "_sgx_mrenclave"
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else
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GRAMINE_ENCRYPTION_KEY = "direct"
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endif
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.PHONY: all
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all: swtpm.manifest
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ifeq ($(SGX),1)
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all: swtpm.manifest.sgx swtpm.sig
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endif
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swtpm.manifest: swtpm.manifest.template
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gramine-manifest \
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-Dlog_level=$(GRAMINE_LOG_LEVEL) \
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-Dencryption_key=$(GRAMINE_ENCRYPTION_KEY) \
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-Darch_libdir=$(ARCH_LIBDIR) \
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-Dentrypoint=$(realpath $(shell sh -c "command -v swtpm")) \
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$< $@
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# gramine-sgx-sign generates both a .sig file and a .manifest.sgx file. This is somewhat
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# hard to express properly in Make. The simple solution would be to use
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# "Rules with Grouped Targets" (`&:`), however make on Ubuntu <= 20.04 doesn't support it.
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#
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# Simply using a normal rule with "two targets" is equivalent to creating separate rules
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# for each of the targets, and when using `make -j`, this might cause two instances
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# of gramine-sgx-sign to get launched simultaneously, potentially breaking the build.
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#
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# As a workaround, we use a dummy intermediate target, and mark both files as depending on it, to
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# get the dependency graph we want. We mark this dummy target as .INTERMEDIATE, which means
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# that make will consider the source tree up-to-date even if the sgx_sign file doesn't exist,
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# as long as the other dependencies check out. This is in contrast to .PHONY, which would
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# be rebuilt on every invocation of make.
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swtpm.sig swtpm.manifest.sgx: sgx_sign
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@:
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.INTERMEDIATE: sgx_sign
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sgx_sign: swtpm.manifest
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gramine-sgx-sign \
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--manifest $< \
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--output $<.sgx
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ifeq ($(SGX),)
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GRAMINE = gramine-direct
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else
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GRAMINE = gramine-sgx
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endif
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.PHONY: clean
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clean:
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$(RM) *.token *.sig *.manifest.sgx *.manifest myvtpm2/.lock myvtpm2/*.permall
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.PHONY: distclean
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distclean: clean

‎swtpm/README.md‎

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# swtpm
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This directory contains a Makefile and a manifest template for running swtpm.
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See https://github.com/stefanberger/swtpm/.
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**NOTE**: Currently works only with PR https://github.com/gramineproject/gramine/pull/1210.
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See also https://github.com/stefanberger/swtpm/issues/792.
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# Installing
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1. Install `libtpms` like this:
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https://github.com/stefanberger/libtpms/wiki#build-a-package-on-ubuntu
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- Version used: `git checkout v0.9.6`
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2. Install `swtpm` like this: https://github.com/stefanberger/swtpm/wiki#compile-on-ubuntu-2104
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- Don't install `libtpms-dev` since we've done it already in step 1
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- Version used: `git checkout v0.8.0`
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Now swtpm tools are installed. We run only `swtpm` executable with Gramine.
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# Configuration of `swtpm`
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`swtpm` executable can be run in several modes. We hard-code the following configuration
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(command-line options) to run with Gramine:
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```sh
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$ swtpm socket --tpm2 --tpmstate dir=/myvtpm2 --seccomp action=none \
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--server type=tcp,port=2321,disconnect --ctrl type=tcp,port=2320 \
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--flags not-need-init,startup-clear
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```
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This configuration means:
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- run `swtpm` in TPM2 mode,
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- save all TPM state under `/myvtpm2/` dir (encrypted under Gramine with SGX),
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- don't use seccomp (Gramine doesn't support it, and it's not needed in Gramine env anyway),
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- listen for client connections on TCP/IP port 2321 (in contrast to CUSE or chardev),
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- create a control channel on TCP/IP port 2320,
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- additional flags for the initial state of TPM.
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For more information, see `man swtpm`.
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# Building
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- `make clean; make` for Gramine without SGX (`gramine-direct`).
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- `make clean; make SGX=1` for Gramine with SGX (`gramine-sgx`).
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You can add `DEBUG=1` for verbose Gramine logs.
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Notice that `gramine-direct` uses a dummy encryption key for TPM files, hard-coded in the manifest.
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Whereas `gramine-sgx` uses the MRENCLAVE-based sealing encryption key for TPM files (and is
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therefore secure). To make sure the correct key is used, we require a `make clean` step. For details
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on how the key is chosen, see Makefile and manifest template.
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# Quick tests of swtpm with Gramine
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# 1. Self-test
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The test idea is taken from https://github.com/stefanberger/swtpm/wiki/Useful-scripts-for-TPM,
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Section "Trigger a self-test on a TPM 2 listening on command port 2321 with the disconnect flag".
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```sh
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# swtpm server in one window
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gramine-sgx swtpm
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# client script in another window
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bash -c "exec 100<>/dev/tcp/localhost/2321; \
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echo -en '\x80\x01\x00\x00\x00\x0b\x00\x00\x01\x43\x01' >&100; \
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od -tx1 <&100"
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## output must be like this:
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## 0000000 80 01 00 00 00 0a 00 00 00 00
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```
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# 2. Hashing in PCR 17
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The test idea is taken from the unit test:
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https://github.com/stefanberger/swtpm/blob/346b3d62/tests/_test_tpm2_hashing.
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```sh
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# swtpm server in one window
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gramine-sgx swtpm
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# client scripts in another window
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## 1 step: init TPM to known state
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swtpm_ioctl --tcp localhost:2320 -i
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## 2 step: startup TPM2
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bash -c "exec 100<>/dev/tcp/localhost/2321; \
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echo -en '\x80\x01\x00\x00\x00\x0c\x00\x00\x01\x44\x00\x00' >&100; \
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od -tx1 <&100"
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## output must be like this:
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## 0000000 80 01 00 00 00 0a 00 00 00 00
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## 3 step: ask TPM to hash string "1234" in PCR 17
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swtpm_ioctl --tcp localhost:2320 -h 1234
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## 4 step: read PCR 17
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bash -c "exec 100<>/dev/tcp/localhost/2321; \
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echo -en '\x80\x01\x00\x00\x00\x14\x00\x00\x01\x7e\x00\x00\x00\x01\x00\x0b\x03\x00\x00\x02' >&100; \
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od -tx1 <&100"
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## output must be like this:
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## 0000000 80 01 00 00 00 3e 00 00 00 00 00 00 00 2c 00 00
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## 0000020 00 01 00 0b 03 00 00 02 00 00 00 01 00 20 fc a5
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## 0000040 d6 49 bf b0 c9 22 fd 33 0f 79 b2 00 43 28 9d af
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## 0000060 d6 0d 01 a4 c4 37 3c f2 8a db 56 c9 b4 54
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## 5 step: check TPM Established flag (must be 1)
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swtpm_ioctl --tcp localhost:2320 -e
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## 6 step: shutdown TPM
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swtpm_ioctl --tcp localhost:2320 -s
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```

‎swtpm/myvtpm2/.dummy‎

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‎swtpm/swtpm.manifest.template‎

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# swtpm (TPM emulator) manifest file example
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loader.entrypoint = "file:{{ gramine.libos }}"
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libos.entrypoint = "{{ entrypoint }}"
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loader.log_level = "{{ log_level }}"
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loader.env.LD_LIBRARY_PATH = "/lib:{{ arch_libdir }}:/usr/{{ arch_libdir }}"
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loader.argv = [
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"swtpm", "socket", "--tpm2",
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"--tpmstate", "dir=/myvtpm2",
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"--seccomp", "action=none",
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"--server", "type=tcp,port=2321,disconnect",
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"--ctrl", "type=tcp,port=2320",
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"--flags", "not-need-init,startup-clear",
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]
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sys.enable_sigterm_injection = true
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sys.enable_extra_runtime_domain_names_conf = true
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fs.mounts = [
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{ path = "/lib", uri = "file:{{ gramine.runtimedir() }}" },
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{ path = "{{ arch_libdir }}", uri = "file:{{ arch_libdir }}" },
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{ path = "/usr/{{ arch_libdir }}", uri = "file:/usr/{{ arch_libdir }}" },
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{ path = "/usr/lib/swtpm/", uri = "file:/usr/lib/swtpm/" },
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{ path = "{{ entrypoint }}", uri = "file:{{ entrypoint }}" },
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{ type = "encrypted", path = "/myvtpm2/", uri = "file:myvtpm2/", key_name = "{{ encryption_key }}" },
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]
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{% if encryption_key == "direct" %}
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fs.insecure__keys.direct = "ffeeddccbbaa99887766554433221100"
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{% endif %}
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sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
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sgx.enclave_size = "1G"
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sgx.trusted_files = [
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"file:{{ gramine.libos }}",
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"file:{{ entrypoint }}",
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"file:{{ gramine.runtimedir() }}/",
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"file:{{ arch_libdir }}/",
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"file:/usr/{{ arch_libdir }}/",
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"file:/usr/lib/swtpm/",
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]

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