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authorEric Biggers <ebiggers@google.com>2022-01-19 03:54:33 +0300
committerJarkko Sakkinen <jarkko@kernel.org>2022-03-08 11:33:18 +0300
commit8f2a7b518bb878c9a8c4f86432908a53e060da1f (patch)
treeb6926c7d2c37632315e959168b1959ff94f69b1e /crypto
parentc51abd96837f600d8fd940b6ab8e2da578575504 (diff)
downloadlinux-8f2a7b518bb878c9a8c4f86432908a53e060da1f.tar.xz
KEYS: x509: clearly distinguish between key and signature algorithms
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 Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/asymmetric_keys/x509.asn12
-rw-r--r--crypto/asymmetric_keys/x509_cert_parser.c32
2 files changed, 19 insertions, 15 deletions
diff --git a/crypto/asymmetric_keys/x509.asn1 b/crypto/asymmetric_keys/x509.asn1
index 5c9f4e4a5231..92d59c32f96a 100644
--- a/crypto/asymmetric_keys/x509.asn1
+++ b/crypto/asymmetric_keys/x509.asn1
@@ -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 }),
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 083405eb80c3..aec2396a7f7e 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -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;
}