| Message ID | 20220823152108.v2.4.I32591db064b6cdc91850d777f363c9d05c985b39@changeid |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Encrypted Hibernation | expand |
On Tue, Aug 23, 2022 at 15:25:20 -0700, Evan Green wrote: > diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst > index 0bfb4c33974890..dc9e11bb4824da 100644 > --- a/Documentation/security/keys/trusted-encrypted.rst > +++ b/Documentation/security/keys/trusted-encrypted.rst > @@ -199,6 +199,10 @@ Usage:: > policyhandle= handle to an authorization policy session that defines the > same policy and with the same hash algorithm as was used to > seal the key. > + creationpcrs= hex integer representing the set of PCR values to be > + included in the PCR creation data. The bit corresponding > + to each PCR should be 1 to be included, 0 to be ignored. > + TPM2 only. There's inconsistent whitespace here. Given the context, I suspect the tabs should be expanded to spaces. As for the docs themselves, this might preferrably mention how large this is supposed to be. It seems to be limited to 32bits by the code. What happens if fewer are provided? More? Will there always be at most 32 PCR values? Also, how are the bits interpreted? I presume bit 0 is for PCR value 0? Thanks for including docs. Thanks, --Ben
On Wed, Aug 24, 2022 at 4:56 AM Ben Boeckel <me@benboeckel.net> wrote: > > On Tue, Aug 23, 2022 at 15:25:20 -0700, Evan Green wrote: > > diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst > > index 0bfb4c33974890..dc9e11bb4824da 100644 > > --- a/Documentation/security/keys/trusted-encrypted.rst > > +++ b/Documentation/security/keys/trusted-encrypted.rst > > @@ -199,6 +199,10 @@ Usage:: > > policyhandle= handle to an authorization policy session that defines the > > same policy and with the same hash algorithm as was used to > > seal the key. > > + creationpcrs= hex integer representing the set of PCR values to be > > + included in the PCR creation data. The bit corresponding > > + to each PCR should be 1 to be included, 0 to be ignored. > > + TPM2 only. > > There's inconsistent whitespace here. Given the context, I suspect the > tabs should be expanded to spaces. > > As for the docs themselves, this might preferrably mention how large > this is supposed to be. It seems to be limited to 32bits by the code. > What happens if fewer are provided? More? Will there always be at most > 32 PCR values? Also, how are the bits interpreted? I presume bit 0 is > for PCR value 0? Makes sense, I'll pin down the specification a bit better here and fix up the spacing. > > Thanks for including docs. Thanks for looking at them! -Evan
diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index 0bfb4c33974890..dc9e11bb4824da 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -199,6 +199,10 @@ Usage:: policyhandle= handle to an authorization policy session that defines the same policy and with the same hash algorithm as was used to seal the key. + creationpcrs= hex integer representing the set of PCR values to be + included in the PCR creation data. The bit corresponding + to each PCR should be 1 to be included, 0 to be ignored. + TPM2 only. "keyctl print" returns an ascii hex copy of the sealed key, which is in standard TPM_STORED_DATA format. The key length for new keys are always in bytes. diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h index 209086fed240a5..8523d41507b2a4 100644 --- a/include/keys/trusted-type.h +++ b/include/keys/trusted-type.h @@ -54,6 +54,7 @@ struct trusted_key_options { uint32_t policydigest_len; unsigned char policydigest[MAX_DIGEST_SIZE]; uint32_t policyhandle; + uint32_t creation_pcrs; }; struct trusted_key_ops { diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index aa108bea6739b3..2975827c01bec0 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -713,6 +713,7 @@ enum { Opt_hash, Opt_policydigest, Opt_policyhandle, + Opt_creationpcrs, }; static const match_table_t key_tokens = { @@ -725,6 +726,7 @@ static const match_table_t key_tokens = { {Opt_hash, "hash=%s"}, {Opt_policydigest, "policydigest=%s"}, {Opt_policyhandle, "policyhandle=%s"}, + {Opt_creationpcrs, "creationpcrs=%s"}, {Opt_err, NULL} }; @@ -858,6 +860,13 @@ static int getoptions(char *c, struct trusted_key_payload *pay, return -EINVAL; opt->policyhandle = handle; break; + case Opt_creationpcrs: + if (!tpm2) + return -EINVAL; + res = kstrtoint(args[0].from, 16, &opt->creation_pcrs); + if (res < 0) + return -EINVAL; + break; default: return -EINVAL; } diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 1f166d4fa307a9..1d1470b880ca01 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -389,7 +389,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip, struct tpm_buf buf; u32 hash; u32 flags; - int i; + int i, j; int rc; for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) { @@ -458,7 +458,28 @@ int tpm2_seal_trusted(struct tpm_chip *chip, tpm_buf_append_u16(&buf, 0); /* creation PCR */ - tpm_buf_append_u32(&buf, 0); + if (options->creation_pcrs) { + /* One bank */ + tpm_buf_append_u32(&buf, 1); + /* Which bank to use */ + tpm_buf_append_u16(&buf, hash); + /* Length of the PCR bitmask */ + tpm_buf_append_u8(&buf, 3); + /* PCR bitmask */ + for (i = 0; i < 3; i++) { + char tmp = 0; + + for (j = 0; j < 8; j++) { + char bit = (i * 8) + j; + + if (options->creation_pcrs & (1 << bit)) + tmp |= (1 << j); + } + tpm_buf_append_u8(&buf, tmp); + } + } else { + tpm_buf_append_u32(&buf, 0); + } if (buf.flags & TPM_BUF_OVERFLOW) { rc = -E2BIG;