KEYS: x509: various cleanups

From: Eric Biggers <[email protected]>

An X.509 certificate has two, potentially different public key
algorithms: the one used by the certificate's key, and the one that was used to sign the certificate. Some of the naming made it unclear which algorithm was meant. Rename things appropriately:

- x509_note_pkey_algo() => x509_note_sig_algo()
- algo_oid => sig_algo

Acked-by Jarkko Sakkinen <[email protected]>

Signed-off-by Eric Biggers <[email protected]>

---
 crypto/asymmetric_keys/x509.asn1          |  2 +-
 crypto/asymmetric_keys/x509_cert_parser.c | 32 +++++++++++++----------
 2 files changed, 19 insertions(+), 15 deletions(-)

crypto/asymmetric_keys/x509.asn1 +1 -1

index 5c9f4e4a52310..92d59c32f96a8 100644
@@ -7,7 +7,7 @@ Certificate ::= SEQUENCE {
 TBSCertificate ::= SEQUENCE {
 	version           [ 0 ]	Version DEFAULT,
 	serialNumber		CertificateSerialNumber ({ x509_note_serial }),
-	signature		AlgorithmIdentifier ({ x509_note_pkey_algo }),
+	signature		AlgorithmIdentifier ({ x509_note_sig_algo }),
 	issuer			Name ({ x509_note_issuer }),
 	validity		Validity,
 	subject			Name ({ x509_note_subject }),

crypto/asymmetric_keys/x509_cert_parser.c +18 -14

index 083405eb80c32..aec2396a7f7e1 100644
@@ -24,9 +24,9 @@ struct x509_parse_context {
 	size_t		key_size;		/* Size of key data */
 	const void	*params;		/* Key parameters */
 	size_t		params_size;		/* Size of key parameters */
-	enum OID	key_algo;		/* Public key algorithm */
+	enum OID	key_algo;		/* Algorithm used by the cert's key */
 	enum OID	last_oid;		/* Last OID encountered */
-	enum OID	algo_oid;		/* Algorithm OID */
+	enum OID	sig_algo;		/* Algorithm used to sign the cert */
 	unsigned char	nr_mpi;			/* Number of MPIs stored */
 	u8		o_size;			/* Size of organizationName (O) */
 	u8		cn_size;		/* Size of commonName (CN) */

@@ -187,11 +187,10 @@ int x509_note_tbs_certificate(void *context, size_t hdrlen,
 }
 
 /*
- * Record the public key algorithm
+ * Record the algorithm that was used to sign this certificate.
  */
-int x509_note_pkey_algo(void *context, size_t hdrlen,
-			unsigned char tag,
-			const void *value, size_t vlen)
+int x509_note_sig_algo(void *context, size_t hdrlen, unsigned char tag,
+		       const void *value, size_t vlen)
 {
 	struct x509_parse_context *ctx = context;
 

@@ -263,22 +262,22 @@ int x509_note_pkey_algo(void *context, size_t hdrlen,
 rsa_pkcs1:
 	ctx->cert->sig->pkey_algo = "rsa";
 	ctx->cert->sig->encoding = "pkcs1";
-	ctx->algo_oid = ctx->last_oid;
+	ctx->sig_algo = ctx->last_oid;
 	return 0;
 ecrdsa:
 	ctx->cert->sig->pkey_algo = "ecrdsa";
 	ctx->cert->sig->encoding = "raw";
-	ctx->algo_oid = ctx->last_oid;
+	ctx->sig_algo = ctx->last_oid;
 	return 0;
 sm2:
 	ctx->cert->sig->pkey_algo = "sm2";
 	ctx->cert->sig->encoding = "raw";
-	ctx->algo_oid = ctx->last_oid;
+	ctx->sig_algo = ctx->last_oid;
 	return 0;
 ecdsa:
 	ctx->cert->sig->pkey_algo = "ecdsa";
 	ctx->cert->sig->encoding = "x962";
-	ctx->algo_oid = ctx->last_oid;
+	ctx->sig_algo = ctx->last_oid;
 	return 0;
 }
 

@@ -291,11 +290,16 @@ int x509_note_signature(void *context, size_t hdrlen,
 {
 	struct x509_parse_context *ctx = context;
 
-	pr_debug("Signature type: %u size %zu\n", ctx->last_oid, vlen);
+	pr_debug("Signature: alg=%u, size=%zu\n", ctx->last_oid, vlen);
 
-	if (ctx->last_oid != ctx->algo_oid) {
-		pr_warn("Got cert with pkey (%u) and sig (%u) algorithm OIDs\n",
-			ctx->algo_oid, ctx->last_oid);
+	/*
+	 * In X.509 certificates, the signature's algorithm is stored in two
+	 * places: inside the TBSCertificate (the data that is signed), and
+	 * alongside the signature.  These *must* match.
+	 */
+	if (ctx->last_oid != ctx->sig_algo) {
+		pr_warn("signatureAlgorithm (%u) differs from tbsCertificate.signature (%u)\n",
+			ctx->last_oid, ctx->sig_algo);
 		return -EINVAL;
 	}
 

Signature · 1 line

2.34.1

From: Eric Biggers <[email protected]>

Remove unused fields from struct x509_parse_context.

Acked-by Jarkko Sakkinen <[email protected]>

Signed-off-by Eric Biggers <[email protected]>

---
 crypto/asymmetric_keys/x509_cert_parser.c | 2 --
 1 file changed, 2 deletions(-)

crypto/asymmetric_keys/x509_cert_parser.c +0 -2

index aec2396a7f7e1..2899ed80bb18e 100644
@@ -19,7 +19,6 @@
 struct x509_parse_context {
 	struct x509_certificate	*cert;		/* Certificate being constructed */
 	unsigned long	data;			/* Start of data */
-	const void	*cert_start;		/* Start of cert content */
 	const void	*key;			/* Key data */
 	size_t		key_size;		/* Size of key data */
 	const void	*params;		/* Key parameters */

@@ -27,7 +26,6 @@ struct x509_parse_context {
 	enum OID	key_algo;		/* Algorithm used by the cert's key */
 	enum OID	last_oid;		/* Last OID encountered */
 	enum OID	sig_algo;		/* Algorithm used to sign the cert */
-	unsigned char	nr_mpi;			/* Number of MPIs stored */
 	u8		o_size;			/* Size of organizationName (O) */
 	u8		cn_size;		/* Size of commonName (CN) */
 	u8		email_size;		/* Size of emailAddress */

Signature · 1 line

2.34.1

From: Eric Biggers <[email protected]>

The X.509 parser always sets cert->pub->pkey_algo on success, since x509_extract_key_data() is a mandatory action in the X.509 ASN.1 grammar, and it returns an error if the algorithm is unknown. Thus, remove the dead code which handled this field being NULL. This results in the ->unsupported_key flag never being set, so remove that too.

Signed-off-by Eric Biggers <[email protected]>

---
 crypto/asymmetric_keys/pkcs7_verify.c    | 7 ++-----
 crypto/asymmetric_keys/x509_parser.h     | 1 -
 crypto/asymmetric_keys/x509_public_key.c | 9 ---------
 3 files changed, 2 insertions(+), 15 deletions(-)

crypto/asymmetric_keys/pkcs7_verify.c +2 -5

index 0b4d07aa88111..d37b187faf9ae 100644
@@ -226,9 +226,6 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
 			return 0;
 		}
 
-		if (x509->unsupported_key)
-			goto unsupported_crypto_in_x509;
-
 		pr_debug("- issuer %s\n", x509->issuer);
 		sig = x509->sig;
 		if (sig->auth_ids[0])

@@ -245,7 +242,7 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
 			 * authority.
 			 */
 			if (x509->unsupported_sig)
-				goto unsupported_crypto_in_x509;
+				goto unsupported_sig_in_x509;
 			x509->signer = x509;
 			pr_debug("- self-signed\n");
 			return 0;

@@ -309,7 +306,7 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
 		might_sleep();
 	}
 
-unsupported_crypto_in_x509:
+unsupported_sig_in_x509:
 	/* Just prune the certificate chain at this point if we lack some
 	 * crypto module to go further.  Note, however, we don't want to set
 	 * sinfo->unsupported_crypto as the signed info block may still be

crypto/asymmetric_keys/x509_parser.h +0 -1

index c233f136fb354..da854c94f1115 100644
@@ -36,7 +36,6 @@ struct x509_certificate {
 	bool		seen;			/* Infinite recursion prevention */
 	bool		verified;
 	bool		self_signed;		/* T if self-signed (check unsupported_sig too) */
-	bool		unsupported_key;	/* T if key uses unsupported crypto */
 	bool		unsupported_sig;	/* T if signature uses unsupported crypto */
 	bool		blacklisted;
 };

crypto/asymmetric_keys/x509_public_key.c +0 -9

index fe14cae115b51..b03d04d78eb9d 100644
@@ -33,9 +33,6 @@ int x509_get_sig_params(struct x509_certificate *cert)
 	sig->data = cert->tbs;
 	sig->data_size = cert->tbs_size;
 
-	if (!cert->pub->pkey_algo)
-		cert->unsupported_key = true;
-
 	if (!sig->pkey_algo)
 		cert->unsupported_sig = true;
 

@@ -173,12 +170,6 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
 
 	pr_devel("Cert Issuer: %s\n", cert->issuer);
 	pr_devel("Cert Subject: %s\n", cert->subject);
-
-	if (cert->unsupported_key) {
-		ret = -ENOPKG;
-		goto error_free_cert;
-	}
-
 	pr_devel("Cert Key Algo: %s\n", cert->pub->pkey_algo);
 	pr_devel("Cert Valid period: %lld-%lld\n", cert->valid_from, cert->valid_to);
 

Signature · 1 line

2.34.1

From: Eric Biggers <[email protected]>

The X.509 parser always sets cert->sig->pkey_algo and cert->sig->hash_algo on success, since x509_note_sig_algo() is a mandatory action in the X.509 ASN.1 grammar, and it returns an error if the signature's algorithm is unknown. Thus, remove the dead code which handled these fields being NULL.

Acked-by Jarkko Sakkinen <[email protected]>

Signed-off-by Eric Biggers <[email protected]>

---
 crypto/asymmetric_keys/x509_public_key.c | 9 ---------
 1 file changed, 9 deletions(-)

crypto/asymmetric_keys/x509_public_key.c +0 -9

index b03d04d78eb9d..8c77a297a82d4 100644
@@ -33,15 +33,6 @@ int x509_get_sig_params(struct x509_certificate *cert)
 	sig->data = cert->tbs;
 	sig->data_size = cert->tbs_size;
 
-	if (!sig->pkey_algo)
-		cert->unsupported_sig = true;
-
-	/* We check the hash if we can - even if we can't then verify it */
-	if (!sig->hash_algo) {
-		cert->unsupported_sig = true;
-		return 0;
-	}
-
 	sig->s = kmemdup(cert->raw_sig, cert->raw_sig_size, GFP_KERNEL);
 	if (!sig->s)
 		return -ENOMEM;

Signature · 1 line

2.34.1

This series cleans up a few things in the X.509 certificate parser.

Changed v1 => v2:
- Renamed label in patch 3
- Added Acked-by's

Eric Biggers (4):
KEYS: x509: clearly distinguish between key and signature algorithms
KEYS: x509: remove unused fields
KEYS: x509: remove never-set ->unsupported_key flag
KEYS: x509: remove dead code that set ->unsupported_sig

 crypto/asymmetric_keys/pkcs7_verify.c     |  7 ++---
 crypto/asymmetric_keys/x509.asn1          |  2 +-
 crypto/asymmetric_keys/x509_cert_parser.c | 34 ++++++++++++-----------
 crypto/asymmetric_keys/x509_parser.h      |  1 -
 crypto/asymmetric_keys/x509_public_key.c  | 18 ------------
 5 files changed, 21 insertions(+), 41 deletions(-)

Signature · 1 line

2.34.1

Quoted 19 lines · Eric Biggers

This series cleans up a few things in the X.509 certificate parser.

Changed v1 => v2:
- Renamed label in patch 3
- Added Acked-by's

Eric Biggers (4):
KEYS: x509: clearly distinguish between key and signature algorithms
KEYS: x509: remove unused fields
KEYS: x509: remove never-set ->unsupported_key flag
KEYS: x509: remove dead code that set ->unsupported_sig

 crypto/asymmetric_keys/pkcs7_verify.c     |  7 ++---
 crypto/asymmetric_keys/x509.asn1          |  2 +-
 crypto/asymmetric_keys/x509_cert_parser.c | 34 ++++++++++++-----------
 crypto/asymmetric_keys/x509_parser.h      |  1 -
 crypto/asymmetric_keys/x509_public_key.c  | 18 ------------
 5 files changed, 21 insertions(+), 41 deletions(-)

Quoted 3 lines

Signature · 1 line

2.34.1

I'll apply these (with ackd -> reviewed).