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qemu-vm: implement virtualization.tpm.provisioning (#364379)
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baloo authored Dec 26, 2024
2 parents b5e12ff + 059a86b commit 28e1cce
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Showing 5 changed files with 206 additions and 3 deletions.
53 changes: 50 additions & 3 deletions nixos/modules/virtualisation/qemu-vm.nix
Original file line number Diff line number Diff line change
Expand Up @@ -228,11 +228,38 @@ let
${lib.getExe cfg.tpm.package} \
socket \
--tpmstate dir="$NIX_SWTPM_DIR" \
--ctrl type=unixio,path="$NIX_SWTPM_DIR"/socket,terminate \
--server type=unixio,path="$NIX_SWTPM_DIR"/socket \
--ctrl type=unixio,path="$NIX_SWTPM_DIR"/socket.ctrl \
--pid file="$NIX_SWTPM_DIR"/pid --daemon \
--flags not-need-init \
--tpm2 \
--log file="$NIX_SWTPM_DIR"/stdout,level=6
(
export TPM2TOOLS_TCTI=swtpm:path="$NIX_SWTPM_DIR"/socket
export PATH=${
lib.makeBinPath [
pkgs.tpm2-tools
]
}:$PATH
tpm2_startup --clear
tpm2_startup
${lib.optionalString (cfg.tpm.provisioning != null)
# Run provisioning in a subshell not to pollute vars
''
(
export TCTI=swtpm:path="$NIX_SWTPM_DIR"/socket
${cfg.tpm.provisioning}
)
''
}
tpm2_shutdown
tpm2_shutdown --clear
)
# Enable `fdflags` builtin in Bash
# We will need it to perform surgical modification of the file descriptor
# passed in the coprocess to remove `FD_CLOEXEC`, i.e. close the file descriptor
Expand All @@ -249,7 +276,7 @@ let
# will stop it.
coproc waitingswtpm {
read || :
echo "" | ${lib.getExe hostPkgs.socat} STDIO UNIX-CONNECT:"$NIX_SWTPM_DIR"/socket
${cfg.tpm.package}/bin/swtpm_ioctl --unix "$NIX_SWTPM_DIR"/socket.ctrl --stop 2>/dev/null
}
# Clear `FD_CLOEXEC` on the coprocess' file descriptor stdin.
fdflags -s-cloexec ''${waitingswtpm[1]}
Expand Down Expand Up @@ -980,6 +1007,26 @@ in
example = "tpm-tis-device";
description = "QEMU device model for the TPM, uses the appropriate default based on th guest platform system and the package passed.";
};

provisioning = mkOption {
type = types.nullOr types.str;
default = null;
description = ''
Script to provision the TPM before control is handed off to the VM.
`TPM2TOOLS_TCTI` will be provided to configure tpm2-tools to use the
swtpm instance transparently.
`TCTI` is also provided as a generic value, consumer is expected to
re-export it however it may need (`TPM2OPENSSL_TCTI`, `TPM2_PKCS11_TCTI`,
...).
'';
example = literalExpression ''
tpm2_nvdefine 0xcafecafe \
-C o \
-a "ownerread|policyread|policywrite|ownerwrite|authread|authwrite"
echo "foobar" | tpm2_nvwrite 0xcafecafe -C o
'';
};
};

virtualisation.useDefaultFilesystems = mkOption {
Expand Down Expand Up @@ -1198,7 +1245,7 @@ in
"-nographic"
])
(mkIf (cfg.tpm.enable) [
"-chardev socket,id=chrtpm,path=\"$NIX_SWTPM_DIR\"/socket"
"-chardev socket,id=chrtpm,path=\"$NIX_SWTPM_DIR\"/socket.ctrl"
"-tpmdev emulator,id=tpm_dev_0,chardev=chrtpm"
"-device ${cfg.tpm.deviceModel},tpmdev=tpm_dev_0"
])
Expand Down
1 change: 1 addition & 0 deletions nixos/tests/all-tests.nix
Original file line number Diff line number Diff line change
Expand Up @@ -1086,6 +1086,7 @@ in {
tmate-ssh-server = handleTest ./tmate-ssh-server.nix { };
tomcat = handleTest ./tomcat.nix {};
tor = handleTest ./tor.nix {};
tpm-ek = handleTest ./tpm-ek {};
traefik = handleTestOn ["aarch64-linux" "x86_64-linux"] ./traefik.nix {};
trafficserver = handleTest ./trafficserver.nix {};
transfer-sh = handleTest ./transfer-sh.nix {};
Expand Down
19 changes: 19 additions & 0 deletions nixos/tests/tpm-ek/ca.crt
Original file line number Diff line number Diff line change
@@ -0,0 +1,19 @@
-----BEGIN CERTIFICATE-----
MIIDHTCCAgWgAwIBAgIUbCWkrXLAgC+z2vWzFcVaS/bHpkkwDQYJKoZIhvcNAQEL
BQAwHjEcMBoGA1UECgwTVmVyeSBsZWdpdCBDQSwgSW5jLjAeFw0yNDEyMTIwMzEy
MTNaFw0zNDEyMTAwMzEyMTNaMB4xHDAaBgNVBAoME1ZlcnkgbGVnaXQgQ0EsIElu
Yy4wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC1tBr/aneQCULixAST
/Gev/ITUYV7QHpgByNcF+yeqMkTigFVcknSwhM6pw++apPARrEjtf3YTzrFAlM7z
mo5M16exbDNKKgTQ90Ms8bvQbeAiHZneWFpT1kuQxcnb0veOsbzM7ksV7qRHCxUN
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ZAfAdfq8mPjFa0cnd2v9IaIgB7cJHlYS1S/LcK9pomw9bQ5AeoRYiEmhX9DxCSH8
r/EnAgMBAAGjUzBRMB0GA1UdDgQWBBQ5PCUBhf4sAWaf4sey5YLj6OWFKTAfBgNV
HSMEGDAWgBQ5PCUBhf4sAWaf4sey5YLj6OWFKTAPBgNVHRMBAf8EBTADAQH/MA0G
CSqGSIb3DQEBCwUAA4IBAQB4x0HI9okWr1/SJkeSQnjVC2QvoxhnoeIkCfXxzr08
ePqAEvMSMocB2OJSZWm+2IXZe3M+ecc3fYPlCRMACghsof9RKwHGt9gyrbL70GBL
7ikJrJRoZ2JGva3AVvLj+bJts1c5j8jpZWK3dCrmJhevzO7agMweJUrj/7oPqqhH
L+VJmfXYK1S25cTei3BsD72gX/DhB0jwKo0Raaj5gO6wR01eR7JPS/E+3lthT8fC
BktxCN5RlMBiNiNfrmHNgg7FZ3ONsi6CIArNFj/wbTM/ic0MSXmkEyskY2NSzSWv
yJ6Z77Zh7MpVkmGsm4hyFzZ2cnTotGoFCd/AGfmj+GlW
-----END CERTIFICATE-----
28 changes: 28 additions & 0 deletions nixos/tests/tpm-ek/ca.priv
Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
-----BEGIN PRIVATE KEY-----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QtS9SXCS8jhf2CAm4ExPopedLJPI8bxiHvS4E3eMt4WzI8cjkEgF9q8nKVxuHWYp
HSuzKwYIn3Q9gu6sucdB8qGezx+9orxpBKqtZ7DGVBsBa5DNmGzKDuRDwfCxx6v1
k0WOPmtyRSh+wHkstAn/MP2v2ajeeUCWlySA96MCgYAqnjyTiaWIK0HZqW3YQcfV
WDg/GqliRJg6mnR6uPHSbIIx2beQM3wowSvi7LEDo8/a27UDfCqL7RtsG/UJ6i4l
9Usuy/odRSzMz9HB2jLYwBkx5LQwT7MaoMHtqWS4T7LRdSdsUXUk9fvCMb4lDUWl
vwXYKH6kQJr7q+hBbBPikA==
-----END PRIVATE KEY-----
108 changes: 108 additions & 0 deletions nixos/tests/tpm-ek/default.nix
Original file line number Diff line number Diff line change
@@ -0,0 +1,108 @@
import ../make-test-python.nix (
{ lib, pkgs, ... }:

let
inherit (pkgs) writeText tpm2-tools openssl;
ek_config = writeText "ek-sign.cnf" ''
[ tpm_policy ]
basicConstraints = CA:FALSE
keyUsage = keyEncipherment
certificatePolicies = 2.23.133.2.1
extendedKeyUsage = 2.23.133.8.1
subjectAltName = ASN1:SEQUENCE:dirname_tpm
[ dirname_tpm ]
seq = EXPLICIT:4,SEQUENCE:dirname_tpm_seq
[ dirname_tpm_seq ]
set = SET:dirname_tpm_set
[ dirname_tpm_set ]
seq.1 = SEQUENCE:dirname_tpm_seq_manufacturer
seq.2 = SEQUENCE:dirname_tpm_seq_model
seq.3 = SEQUENCE:dirname_tpm_seq_version
# We're going to mock up an STM TPM here
[dirname_tpm_seq_manufacturer]
oid = OID:2.23.133.2.1
str = UTF8:"id:53544D20"
[dirname_tpm_seq_model]
oid = OID:2.23.133.2.2
str = UTF8:"ST33HTPHAHD4
[dirname_tpm_seq_version]
oid = OID:2.23.133.2.3
str = UTF8:"id:00010101"
'';
in
{
name = "tpm-ek";

meta = {
maintainers = with lib.maintainers; [ baloo ];
};

nodes.machine =
{ pkgs, ... }:
{
environment.systemPackages = [
openssl
tpm2-tools
];

security.tpm2 = {
enable = true;
tctiEnvironment.enable = true;
};

virtualisation.tpm = {
enable = true;
provisioning = ''
export PATH=${
lib.makeBinPath [
openssl
]
}:$PATH
tpm2_createek -G rsa -u ek.pub -c ek.ctx -f pem
# Sign a certificate
# Pretend we're an STM TPM
openssl x509 \
-extfile ${ek_config} \
-new -days 365 \
\
-subj "/CN=this.is.required.but.it.should.not/" \
-extensions tpm_policy \
\
-CA ${./ca.crt} -CAkey ${./ca.priv} \
\
-out device.der -outform der \
-force_pubkey ek.pub
# Create a nvram slot for the certificate, and we need the size
# to precisely match the length of the certificate we're going to
# put in.
tpm2_nvdefine 0x01c00002 \
-C o \
-a "ownerread|policyread|policywrite|ownerwrite|authread|authwrite" \
-s "$(wc -c device.der| cut -f 1 -d ' ')"
tpm2_nvwrite 0x01c00002 -C o -i device.der
'';
};
};

testScript = ''
start_all()
machine.wait_for_unit("multi-user.target")
machine.succeed('tpm2_nvread 0x01c00002 | openssl x509 -inform der -out /tmp/ek.pem')
print(machine.succeed('openssl x509 -in /tmp/ek.pem -text'))
machine.succeed('openssl verify -CAfile ${./ca.crt} /tmp/ek.pem')
'';
}
)

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