Hi Jarkko, On Tue, May 25, 2021 at 12:33:34AM +0300, Jarkko Sakkinen wrote: > On Mon, May 24, 2021 at 10:15:37AM +0800, Lee, Chun-Yi wrote: > > This patch adds the logic for parsing the CodeSign extended key usage > > extension in X.509. The parsing result will be set to the eku flag > > which is carried by public key. It can be used in the PKCS#7 > > verification. > > > > Signed-off-by: "Lee, Chun-Yi" <jlee@xxxxxxxx> > > --- > > crypto/asymmetric_keys/x509_cert_parser.c | 25 +++++++++++++++++++++++++ > > include/crypto/public_key.h | 1 + > > include/linux/oid_registry.h | 5 +++++ > > 3 files changed, 31 insertions(+) > > > > diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c > > index 6d003096b5bc..996db9419474 100644 > > --- a/crypto/asymmetric_keys/x509_cert_parser.c > > +++ b/crypto/asymmetric_keys/x509_cert_parser.c > > @@ -542,6 +542,8 @@ int x509_process_extension(void *context, size_t hdrlen, > > struct x509_parse_context *ctx = context; > > struct asymmetric_key_id *kid; > > const unsigned char *v = value; > > + int i = 0; > > + enum OID oid; > > > > pr_debug("Extension: %u\n", ctx->last_oid); > > > > @@ -571,6 +573,29 @@ int x509_process_extension(void *context, size_t hdrlen, > > return 0; > > } > > > > + if (ctx->last_oid == OID_extKeyUsage) { > > + if (vlen < 2 || > > + v[0] != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ) || > > + v[1] != vlen - 2) > > + return -EBADMSG; > > + i += 2; > > + > > + while (i < vlen) { > > + /* A 10 bytes EKU OID Octet blob = > > + * ASN1_OID + size byte + 8 bytes OID */ > > + if ((i + 10) > vlen || v[i] != ASN1_OID || v[i + 1] != 8) > > + return -EBADMSG; > > + > > + oid = look_up_OID(v + i + 2, v[i + 1]); > > + if (oid == OID_codeSigning) { > > + ctx->cert->pub->eku |= EKU_codeSigning; > > + } > > + i += 10; > > + } > > + pr_debug("extKeyUsage: %d\n", ctx->cert->pub->eku); > > + return 0; > > + } > > + > > return 0; > > } > > > > diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h > > index 47accec68cb0..1ccaebe2a28b 100644 > > --- a/include/crypto/public_key.h > > +++ b/include/crypto/public_key.h > > @@ -28,6 +28,7 @@ struct public_key { > > bool key_is_private; > > const char *id_type; > > const char *pkey_algo; > > + unsigned int eku : 9; /* Extended Key Usage (9-bit) */ > > Why no just name it ext_key_usage? I get the use of "EKU" elsewhere > but not in the variable name. Now you have to remember too much > context when just looking at this (and it's even undocumented to > add that). > Thanks for your suggestion. I will use a better name in next version. Joey Lee > > }; > > > > extern void public_key_free(struct public_key *key); > > diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h > > index 461b7aa587ba..8c8935f0eb73 100644 > > --- a/include/linux/oid_registry.h > > +++ b/include/linux/oid_registry.h > > @@ -125,9 +125,14 @@ enum OID { > > OID_TPMImportableKey, /* 2.23.133.10.1.4 */ > > OID_TPMSealedData, /* 2.23.133.10.1.5 */ > > > > + /* Extended key purpose OIDs [RFC 5280] */ > > + OID_codeSigning, /* 1.3.6.1.5.5.7.3.3 */ > > + > > OID__NR > > }; > > > > +#define EKU_codeSigning (1 << 2) > > + > > extern enum OID look_up_OID(const void *data, size_t datasize); > > extern int parse_OID(const void *data, size_t datasize, enum OID *oid); > > extern int sprint_oid(const void *, size_t, char *, size_t); > > -- > > 2.16.4 > > > >005diaq6539262 > > > /Jarkko