diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml index b6e71cce2ba..bad21ceb0c2 100644 --- a/man/systemd.exec.xml +++ b/man/systemd.exec.xml @@ -3154,7 +3154,13 @@ StandardInputData=V2XigLJyZSBubyBzdHJhbmdlcnMgdG8gbG92ZQpZb3Uga25vdyB0aGUgcnVsZX authenticated credentials improves security as credentials are not stored in plaintext and only authenticated and decrypted into plaintext the moment a service requiring them is started. Moreover, credentials may be bound to the local hardware and installations, so that they cannot easily be - analyzed offline, or be generated externally. + analyzed offline, or be generated externally. When DevicePolicy= is set to + closed or strict, or set to auto and + DeviceAllow= is set, or PrivateDevices= is set, then this + setting adds /dev/tpmrm0 with rw mode to + DeviceAllow=. See + systemd.resource-control5 + for the details about DevicePolicy= or DeviceAllow=. The credential files/IPC sockets must be accessible to the service manager, but don't have to be directly accessible to the unit's processes: the credential data is read and copied into separate, diff --git a/src/core/unit.c b/src/core/unit.c index 499e9b40eda..78a1f72f7fd 100644 --- a/src/core/unit.c +++ b/src/core/unit.c @@ -4169,6 +4169,16 @@ int unit_patch_contexts(Unit *u) { if (r < 0) return r; } + + /* If there are encrypted credentials we might need to access the TPM. */ + ExecLoadCredential *cred; + HASHMAP_FOREACH(cred, ec->load_credentials) + if (cred->encrypted) { + r = cgroup_add_device_allow(cc, "/dev/tpmrm0", "rw"); + if (r < 0) + return r; + break; + } } } diff --git a/test/units/testsuite-70.sh b/test/units/testsuite-70.sh index 589baf370fc..54e30642a5a 100755 --- a/test/units/testsuite-70.sh +++ b/test/units/testsuite-70.sh @@ -208,6 +208,12 @@ else echo "/usr/lib/systemd/systemd-pcrphase or PCR sysfs files not found, skipping PCR extension test case" fi +# Ensure that sandboxing doesn't stop creds from being accessible +echo "test" > /tmp/testdata +systemd-creds encrypt /tmp/testdata /tmp/testdata.encrypted --with-key=tpm2 +systemd-run -p PrivateDevices=yes -p LoadCredentialEncrypted=testdata.encrypted:/tmp/testdata.encrypted --pipe --wait systemd-creds cat testdata.encrypted | cmp - /tmp/testdata +rm /tmp/testdata + echo OK >/testok exit 0