| Message ID | 20221214003401.4086781-5-eric.snowberg@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add CA enforcement keyring restrictions | expand |
On Tue, 2022-12-13 at 19:33 -0500, Eric Snowberg wrote: > Parse the X.509 Key Usage. The key usage extension defines the purpose of > the key contained in the certificate. > > id-ce-keyUsage OBJECT IDENTIFIER ::= { id-ce 15 } > > KeyUsage ::= BIT STRING { > digitalSignature (0), > contentCommitment (1), > keyEncipherment (2), > dataEncipherment (3), > keyAgreement (4), > keyCertSign (5), > cRLSign (6), > encipherOnly (7), > decipherOnly (8) } > > If the keyCertSign is set, store it in the x509_certificate structure. > This will be used in a follow on patch that requires knowing the > certificate key usage type. Either in this patch or separately, the "digitalSignature" key usage flag needs to be saved. > > Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> > --- > crypto/asymmetric_keys/x509_cert_parser.c | 22 ++++++++++++++++++++++ > crypto/asymmetric_keys/x509_parser.h | 1 + > 2 files changed, 23 insertions(+) > > diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c > index b4443e507153..edb22cf04eed 100644 > --- a/crypto/asymmetric_keys/x509_cert_parser.c > +++ b/crypto/asymmetric_keys/x509_cert_parser.c > @@ -579,6 +579,28 @@ int x509_process_extension(void *context, size_t hdrlen, > return 0; > } > > + if (ctx->last_oid == OID_keyUsage) { > + /* > + * Get hold of the keyUsage bit string to validate keyCertSign > + * v[1] is the encoding size > + * (Expect either 0x02 or 0x03, making it 1 or 2 bytes) > + * v[2] is the number of unused bits in the bit string > + * (If >= 3 keyCertSign is missing) > + * v[3] and possibly v[4] contain the bit string > + * 0x04 is where KeyCertSign lands in this bit string (from > + * RFC 5280 4.2.1.3) > + */ > + if (v[0] != ASN1_BTS) > + return -EBADMSG; > + if (vlen < 4) > + return -EBADMSG; > + if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04)) > + ctx->cert->kcs_set = true; > + else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04)) > + ctx->cert->kcs_set = true; > + return 0; > + } > + > if (ctx->last_oid == OID_authorityKeyIdentifier) { > /* Get hold of the CA key fingerprint */ > ctx->raw_akid = v; > diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h > index 7c5c0ad1c22e..74a9f929e400 100644 > --- a/crypto/asymmetric_keys/x509_parser.h > +++ b/crypto/asymmetric_keys/x509_parser.h > @@ -39,6 +39,7 @@ struct x509_certificate { > bool unsupported_sig; /* T if signature uses unsupported crypto */ > bool blacklisted; > bool root_ca; /* T if basic constraints CA is set */ > + bool kcs_set; /* T if keyCertSign is set */ Using acronyms as variable names makes reviewing code more difficult. Perhaps rename "kcs_set" to either "key_cert_sign" or "keycertsign". > }; > > /*
On Tue, Dec 13, 2022 at 07:33:55PM -0500, Eric Snowberg wrote: > Parse the X.509 Key Usage. The key usage extension defines the purpose of > the key contained in the certificate. > > id-ce-keyUsage OBJECT IDENTIFIER ::= { id-ce 15 } > > KeyUsage ::= BIT STRING { > digitalSignature (0), > contentCommitment (1), > keyEncipherment (2), > dataEncipherment (3), > keyAgreement (4), > keyCertSign (5), > cRLSign (6), > encipherOnly (7), > decipherOnly (8) } > > If the keyCertSign is set, store it in the x509_certificate structure. > This will be used in a follow on patch that requires knowing the > certificate key usage type. > > Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> > --- > crypto/asymmetric_keys/x509_cert_parser.c | 22 ++++++++++++++++++++++ > crypto/asymmetric_keys/x509_parser.h | 1 + > 2 files changed, 23 insertions(+) > > diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c > index b4443e507153..edb22cf04eed 100644 > --- a/crypto/asymmetric_keys/x509_cert_parser.c > +++ b/crypto/asymmetric_keys/x509_cert_parser.c > @@ -579,6 +579,28 @@ int x509_process_extension(void *context, size_t hdrlen, > return 0; > } > > + if (ctx->last_oid == OID_keyUsage) { > + /* > + * Get hold of the keyUsage bit string to validate keyCertSign > + * v[1] is the encoding size > + * (Expect either 0x02 or 0x03, making it 1 or 2 bytes) > + * v[2] is the number of unused bits in the bit string > + * (If >= 3 keyCertSign is missing) > + * v[3] and possibly v[4] contain the bit string > + * 0x04 is where KeyCertSign lands in this bit string (from > + * RFC 5280 4.2.1.3) > + */ > + if (v[0] != ASN1_BTS) > + return -EBADMSG; > + if (vlen < 4) > + return -EBADMSG; > + if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04)) > + ctx->cert->kcs_set = true; > + else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04)) > + ctx->cert->kcs_set = true; > + return 0; This is much more easier to follow thanks to explanation. > + } > + > if (ctx->last_oid == OID_authorityKeyIdentifier) { > /* Get hold of the CA key fingerprint */ > ctx->raw_akid = v; > diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h > index 7c5c0ad1c22e..74a9f929e400 100644 > --- a/crypto/asymmetric_keys/x509_parser.h > +++ b/crypto/asymmetric_keys/x509_parser.h > @@ -39,6 +39,7 @@ struct x509_certificate { > bool unsupported_sig; /* T if signature uses unsupported crypto */ > bool blacklisted; > bool root_ca; /* T if basic constraints CA is set */ > + bool kcs_set; /* T if keyCertSign is set */ > }; > > /* > -- > 2.27.0 > LGTM but I'll hold with reviewed-by's up until the patch set overally looks good to me and I have actually tested it. BR, Jarkko
> On Jan 4, 2023, at 4:43 AM, Jarkko Sakkinen <jarkko@kernel.org> wrote: > > On Tue, Dec 13, 2022 at 07:33:55PM -0500, Eric Snowberg wrote: >> Parse the X.509 Key Usage. The key usage extension defines the purpose of >> the key contained in the certificate. >> >> id-ce-keyUsage OBJECT IDENTIFIER ::= { id-ce 15 } >> >> KeyUsage ::= BIT STRING { >> digitalSignature (0), >> contentCommitment (1), >> keyEncipherment (2), >> dataEncipherment (3), >> keyAgreement (4), >> keyCertSign (5), >> cRLSign (6), >> encipherOnly (7), >> decipherOnly (8) } >> >> If the keyCertSign is set, store it in the x509_certificate structure. >> This will be used in a follow on patch that requires knowing the >> certificate key usage type. >> >> Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> >> --- >> crypto/asymmetric_keys/x509_cert_parser.c | 22 ++++++++++++++++++++++ >> crypto/asymmetric_keys/x509_parser.h | 1 + >> 2 files changed, 23 insertions(+) >> >> diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c >> index b4443e507153..edb22cf04eed 100644 >> --- a/crypto/asymmetric_keys/x509_cert_parser.c >> +++ b/crypto/asymmetric_keys/x509_cert_parser.c >> @@ -579,6 +579,28 @@ int x509_process_extension(void *context, size_t hdrlen, >> return 0; >> } >> >> + if (ctx->last_oid == OID_keyUsage) { >> + /* >> + * Get hold of the keyUsage bit string to validate keyCertSign >> + * v[1] is the encoding size >> + * (Expect either 0x02 or 0x03, making it 1 or 2 bytes) >> + * v[2] is the number of unused bits in the bit string >> + * (If >= 3 keyCertSign is missing) >> + * v[3] and possibly v[4] contain the bit string >> + * 0x04 is where KeyCertSign lands in this bit string (from >> + * RFC 5280 4.2.1.3) >> + */ >> + if (v[0] != ASN1_BTS) >> + return -EBADMSG; >> + if (vlen < 4) >> + return -EBADMSG; >> + if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04)) >> + ctx->cert->kcs_set = true; >> + else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04)) >> + ctx->cert->kcs_set = true; >> + return 0; > > This is much more easier to follow thanks to explanation. > >> + } >> + >> if (ctx->last_oid == OID_authorityKeyIdentifier) { >> /* Get hold of the CA key fingerprint */ >> ctx->raw_akid = v; >> diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h >> index 7c5c0ad1c22e..74a9f929e400 100644 >> --- a/crypto/asymmetric_keys/x509_parser.h >> +++ b/crypto/asymmetric_keys/x509_parser.h >> @@ -39,6 +39,7 @@ struct x509_certificate { >> bool unsupported_sig; /* T if signature uses unsupported crypto */ >> bool blacklisted; >> bool root_ca; /* T if basic constraints CA is set */ >> + bool kcs_set; /* T if keyCertSign is set */ >> }; >> >> /* >> -- >> 2.27.0 >> > > LGTM but I'll hold with reviewed-by's up until the patch set overally > looks good to me and I have actually tested it. Thanks for your review. I will make all the other changes you brought up with the other patches in the next round.
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c index b4443e507153..edb22cf04eed 100644 --- a/crypto/asymmetric_keys/x509_cert_parser.c +++ b/crypto/asymmetric_keys/x509_cert_parser.c @@ -579,6 +579,28 @@ int x509_process_extension(void *context, size_t hdrlen, return 0; } + if (ctx->last_oid == OID_keyUsage) { + /* + * Get hold of the keyUsage bit string to validate keyCertSign + * v[1] is the encoding size + * (Expect either 0x02 or 0x03, making it 1 or 2 bytes) + * v[2] is the number of unused bits in the bit string + * (If >= 3 keyCertSign is missing) + * v[3] and possibly v[4] contain the bit string + * 0x04 is where KeyCertSign lands in this bit string (from + * RFC 5280 4.2.1.3) + */ + if (v[0] != ASN1_BTS) + return -EBADMSG; + if (vlen < 4) + return -EBADMSG; + if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04)) + ctx->cert->kcs_set = true; + else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04)) + ctx->cert->kcs_set = true; + return 0; + } + if (ctx->last_oid == OID_authorityKeyIdentifier) { /* Get hold of the CA key fingerprint */ ctx->raw_akid = v; diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h index 7c5c0ad1c22e..74a9f929e400 100644 --- a/crypto/asymmetric_keys/x509_parser.h +++ b/crypto/asymmetric_keys/x509_parser.h @@ -39,6 +39,7 @@ struct x509_certificate { bool unsupported_sig; /* T if signature uses unsupported crypto */ bool blacklisted; bool root_ca; /* T if basic constraints CA is set */ + bool kcs_set; /* T if keyCertSign is set */ }; /*
Parse the X.509 Key Usage. The key usage extension defines the purpose of the key contained in the certificate. id-ce-keyUsage OBJECT IDENTIFIER ::= { id-ce 15 } KeyUsage ::= BIT STRING { digitalSignature (0), contentCommitment (1), keyEncipherment (2), dataEncipherment (3), keyAgreement (4), keyCertSign (5), cRLSign (6), encipherOnly (7), decipherOnly (8) } If the keyCertSign is set, store it in the x509_certificate structure. This will be used in a follow on patch that requires knowing the certificate key usage type. Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> --- crypto/asymmetric_keys/x509_cert_parser.c | 22 ++++++++++++++++++++++ crypto/asymmetric_keys/x509_parser.h | 1 + 2 files changed, 23 insertions(+)