[PATCH 1/4] X.509: Add CodeSigning extended key usage parsing
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STALE2034d
SUPERSEDED
From: Lee, Chun-Yi <hidden>
Date: 2021-03-23 03:56:33
Also in:
keyrings, lkml
Subsystem:
asymmetric keys, crypto api, the rest · Maintainers:
David Howells, Lukas Wunner, Ignat Korchagin, Herbert Xu, "David S. Miller", Linus Torvalds
Revision v5 of 14 in this series.
Revisions (14)
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@suse.com> --- crypto/asymmetric_keys/x509_cert_parser.c | 24 ++++++++++++++++++++++++ include/crypto/public_key.h | 1 + include/linux/oid_registry.h | 5 +++++ 3 files changed, 30 insertions(+)
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 52c9b455fc7d..65721313b265 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c@@ -497,6 +497,8 @@ 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);
@@ -526,6 +528,28 @@ int x509_process_extension(void *context, size_t hdrlen, return 0; } + if (ctx->last_oid == OID_extKeyUsage) { + if (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 (v[i] != ASN1_OID || v[i + 1] != 8 || (i + 10) > vlen) + 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) */ }; extern void public_key_free(struct public_key *key);
diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
index 4462ed2c18cd..e20e8eb53b21 100644
--- a/include/linux/oid_registry.h
+++ b/include/linux/oid_registry.h@@ -113,9 +113,14 @@ enum OID { OID_SM2_with_SM3, /* 1.2.156.10197.1.501 */ OID_sm3WithRSAEncryption, /* 1.2.156.10197.1.504 */ + /* 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 sprint_oid(const void *, size_t, char *, size_t); extern int sprint_OID(enum OID, char *, size_t);
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2.16.4