[RFC PATCH 4/7] X.509: Retain the key verification data

From: David Howells
Date: Mon Feb 29 2016 - 13:22:15 EST

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Retain the key verification data (ie. the struct public_key_signature)
including the digest and the key identifiers.

Note that this means that we need to take a separate copy of the digest in
x509_get_sig_params() rather than lumping it in with the crypto layer data.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

crypto/asymmetric_keys/pkcs7_trust.c | 8 ++--
crypto/asymmetric_keys/pkcs7_verify.c | 20 +++++-----
crypto/asymmetric_keys/x509_cert_parser.c | 40 ++++++++++---------
crypto/asymmetric_keys/x509_parser.h | 4 --
crypto/asymmetric_keys/x509_public_key.c | 61 +++++++++++++++--------------
5 files changed, 67 insertions(+), 66 deletions(-)

diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index 3bbdcc79a3d3..bf89e006bd07 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -80,16 +80,16 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,

might_sleep();
last = x509;
- sig = &last->sig;
+ sig = last->sig;
}

/* No match - see if the root certificate has a signer amongst the
* trusted keys.
*/
- if (last && (last->akid_id || last->akid_skid)) {
+ if (last && (last->sig->auth_ids[0] || last->sig->auth_ids[1])) {
key = x509_request_asymmetric_key(trust_keyring,
- last->akid_id,
- last->akid_skid,
+ last->sig->auth_ids[0],
+ last->sig->auth_ids[1],
false);
if (!IS_ERR(key)) {
x509 = last;
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index 50be2a15e531..d8d8d234874e 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -174,6 +174,7 @@ static int pkcs7_find_key(struct pkcs7_message *pkcs7,
static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
struct pkcs7_signed_info *sinfo)
{
+ struct public_key_signature *sig;
struct x509_certificate *x509 = sinfo->signer, *p;
struct asymmetric_key_id *auth;
int ret;
@@ -193,14 +194,15 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
goto maybe_missing_crypto_in_x509;

pr_debug("- issuer %s\n", x509->issuer);
- if (x509->akid_id)
+ sig = x509->sig;
+ if (sig->auth_ids[0])
pr_debug("- authkeyid.id %*phN\n",
- x509->akid_id->len, x509->akid_id->data);
- if (x509->akid_skid)
+ sig->auth_ids[0]->len, sig->auth_ids[0]->data);
+ if (sig->auth_ids[1])
pr_debug("- authkeyid.skid %*phN\n",
- x509->akid_skid->len, x509->akid_skid->data);
+ sig->auth_ids[1]->len, sig->auth_ids[1]->data);

- if ((!x509->akid_id && !x509->akid_skid) ||
+ if ((!x509->sig->auth_ids[0] && !x509->sig->auth_ids[1]) ||
strcmp(x509->subject, x509->issuer) == 0) {
/* If there's no authority certificate specified, then
* the certificate must be self-signed and is the root
@@ -224,7 +226,7 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
/* Look through the X.509 certificates in the PKCS#7 message's
* list to see if the next one is there.
*/
- auth = x509->akid_id;
+ auth = sig->auth_ids[0];
if (auth) {
pr_debug("- want %*phN\n", auth->len, auth->data);
for (p = pkcs7->certs; p; p = p->next) {
@@ -234,7 +236,7 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
goto found_issuer_check_skid;
}
} else {
- auth = x509->akid_skid;
+ auth = sig->auth_ids[1];
pr_debug("- want %*phN\n", auth->len, auth->data);
for (p = pkcs7->certs; p; p = p->next) {
if (!p->skid)
@@ -254,8 +256,8 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
/* We matched issuer + serialNumber, but if there's an
* authKeyId.keyId, that must match the CA subjKeyId also.
*/
- if (x509->akid_skid &&
- !asymmetric_key_id_same(p->skid, x509->akid_skid)) {
+ if (sig->auth_ids[1] &&
+ !asymmetric_key_id_same(p->skid, sig->auth_ids[1])) {
pr_warn("Sig %u: X.509 chain contains auth-skid nonmatch (%u->%u)\n",
sinfo->index, x509->index, p->index);
return -EKEYREJECTED;
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 05251c7f9a03..a2fefa713614 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -48,14 +48,11 @@ void x509_free_certificate(struct x509_certificate *cert)
{
if (cert) {
public_key_free(cert->pub);
+ public_key_signature_free(cert->sig);
kfree(cert->issuer);
kfree(cert->subject);
kfree(cert->id);
kfree(cert->skid);
- kfree(cert->akid_id);
- kfree(cert->akid_skid);
- kfree(cert->sig.digest);
- kfree(cert->sig.s);
kfree(cert);
}
}
@@ -78,6 +75,9 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);
if (!cert->pub)
goto error_no_ctx;
+ cert->sig = kzalloc(sizeof(struct public_key_signature), GFP_KERNEL);
+ if (!cert->sig)
+ goto error_no_ctx;
ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL);
if (!ctx)
goto error_no_ctx;
@@ -188,33 +188,33 @@ int x509_note_pkey_algo(void *context, size_t hdrlen,
return -ENOPKG; /* Unsupported combination */

case OID_md4WithRSAEncryption:
- ctx->cert->sig.hash_algo = "md4";
- ctx->cert->sig.pkey_algo = "rsa";
+ ctx->cert->sig->hash_algo = "md4";
+ ctx->cert->sig->pkey_algo = "rsa";
break;

case OID_sha1WithRSAEncryption:
- ctx->cert->sig.hash_algo = "sha1";
- ctx->cert->sig.pkey_algo = "rsa";
+ ctx->cert->sig->hash_algo = "sha1";
+ ctx->cert->sig->pkey_algo = "rsa";
break;

case OID_sha256WithRSAEncryption:
- ctx->cert->sig.hash_algo = "sha256";
- ctx->cert->sig.pkey_algo = "rsa";
+ ctx->cert->sig->hash_algo = "sha256";
+ ctx->cert->sig->pkey_algo = "rsa";
break;

case OID_sha384WithRSAEncryption:
- ctx->cert->sig.hash_algo = "sha384";
- ctx->cert->sig.pkey_algo = "rsa";
+ ctx->cert->sig->hash_algo = "sha384";
+ ctx->cert->sig->pkey_algo = "rsa";
break;

case OID_sha512WithRSAEncryption:
- ctx->cert->sig.hash_algo = "sha512";
- ctx->cert->sig.pkey_algo = "rsa";
+ ctx->cert->sig->hash_algo = "sha512";
+ ctx->cert->sig->pkey_algo = "rsa";
break;

case OID_sha224WithRSAEncryption:
- ctx->cert->sig.hash_algo = "sha224";
- ctx->cert->sig.pkey_algo = "rsa";
+ ctx->cert->sig->hash_algo = "sha224";
+ ctx->cert->sig->pkey_algo = "rsa";
break;
}

@@ -572,14 +572,14 @@ int x509_akid_note_kid(void *context, size_t hdrlen,

pr_debug("AKID: keyid: %*phN\n", (int)vlen, value);

- if (ctx->cert->akid_skid)
+ if (ctx->cert->sig->auth_ids[1])
return 0;

kid = asymmetric_key_generate_id(value, vlen, "", 0);
if (IS_ERR(kid))
return PTR_ERR(kid);
pr_debug("authkeyid %*phN\n", kid->len, kid->data);
- ctx->cert->akid_skid = kid;
+ ctx->cert->sig->auth_ids[1] = kid;
return 0;
}

@@ -611,7 +611,7 @@ int x509_akid_note_serial(void *context, size_t hdrlen,

pr_debug("AKID: serial: %*phN\n", (int)vlen, value);

- if (!ctx->akid_raw_issuer || ctx->cert->akid_id)
+ if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0])
return 0;

kid = asymmetric_key_generate_id(value,
@@ -622,6 +622,6 @@ int x509_akid_note_serial(void *context, size_t hdrlen,
return PTR_ERR(kid);

pr_debug("authkeyid %*phN\n", kid->len, kid->data);
- ctx->cert->akid_id = kid;
+ ctx->cert->sig->auth_ids[0] = kid;
return 0;
}
diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h
index dbeed6018e63..26a4d83e4e6d 100644
--- a/crypto/asymmetric_keys/x509_parser.h
+++ b/crypto/asymmetric_keys/x509_parser.h
@@ -17,13 +17,11 @@ struct x509_certificate {
struct x509_certificate *next;
struct x509_certificate *signer; /* Certificate that signed this one */
struct public_key *pub; /* Public key details */
- struct public_key_signature sig; /* Signature parameters */
+ struct public_key_signature *sig; /* Signature parameters */
char *issuer; /* Name of certificate issuer */
char *subject; /* Name of certificate subject */
struct asymmetric_key_id *id; /* Issuer + Serial number */
struct asymmetric_key_id *skid; /* Subject + subjectKeyId (optional) */
- struct asymmetric_key_id *akid_id; /* CA AuthKeyId matching ->id (optional) */
- struct asymmetric_key_id *akid_skid; /* CA AuthKeyId matching ->skid (optional) */
time64_t valid_from;
time64_t valid_to;
const void *tbs; /* Signed data */
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 2fcf707fb208..4cd102de174c 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -153,30 +153,29 @@ EXPORT_SYMBOL_GPL(x509_request_asymmetric_key);
*/
int x509_get_sig_params(struct x509_certificate *cert)
{
+ struct public_key_signature *sig = cert->sig;
struct crypto_shash *tfm;
struct shash_desc *desc;
- size_t digest_size, desc_size;
- void *digest;
+ size_t desc_size;
int ret;

pr_devel("==>%s()\n", __func__);

if (cert->unsupported_crypto)
return -ENOPKG;
- if (cert->sig.s)
+ if (sig->s)
return 0;

- cert->sig.s = kmemdup(cert->raw_sig, cert->raw_sig_size,
- GFP_KERNEL);
- if (!cert->sig.s)
+ sig->s = kmemdup(cert->raw_sig, cert->raw_sig_size, GFP_KERNEL);
+ if (!sig->s)
return -ENOMEM;

- cert->sig.s_size = cert->raw_sig_size;
+ sig->s_size = cert->raw_sig_size;

/* Allocate the hashing algorithm we're going to need and find out how
* big the hash operational data will be.
*/
- tfm = crypto_alloc_shash(cert->sig.hash_algo, 0, 0);
+ tfm = crypto_alloc_shash(sig->hash_algo, 0, 0);
if (IS_ERR(tfm)) {
if (PTR_ERR(tfm) == -ENOENT) {
cert->unsupported_crypto = true;
@@ -186,29 +185,28 @@ int x509_get_sig_params(struct x509_certificate *cert)
}

desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
- digest_size = crypto_shash_digestsize(tfm);
+ sig->digest_size = crypto_shash_digestsize(tfm);

- /* We allocate the hash operational data storage on the end of the
- * digest storage space.
- */
ret = -ENOMEM;
- digest = kzalloc(ALIGN(digest_size, __alignof__(*desc)) + desc_size,
- GFP_KERNEL);
- if (!digest)
+ sig->digest = kmalloc(sig->digest_size, GFP_KERNEL);
+ if (!sig->digest)
goto error;

- cert->sig.digest = digest;
- cert->sig.digest_size = digest_size;
+ desc = kzalloc(desc_size, GFP_KERNEL);
+ if (!desc)
+ goto error;

- desc = PTR_ALIGN(digest + digest_size, __alignof__(*desc));
desc->tfm = tfm;
desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;

ret = crypto_shash_init(desc);
if (ret < 0)
- goto error;
+ goto error_2;
might_sleep();
- ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, digest);
+ ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, sig->digest);
+
+error_2:
+ kfree(desc);
error:
crypto_free_shash(tfm);
pr_devel("<==%s() = %d\n", __func__, ret);
@@ -230,7 +228,7 @@ int x509_check_signature(const struct public_key *pub,
if (ret < 0)
return ret;

- ret = public_key_verify_signature(pub, &cert->sig);
+ ret = public_key_verify_signature(pub, cert->sig);
if (ret == -ENOPKG)
cert->unsupported_crypto = true;
pr_debug("Cert Verification: %d\n", ret);
@@ -250,17 +248,18 @@ EXPORT_SYMBOL_GPL(x509_check_signature);
static int x509_validate_trust(struct x509_certificate *cert,
struct key *trust_keyring)
{
+ struct public_key_signature *sig = cert->sig;
struct key *key;
int ret = 1;

if (!trust_keyring)
return -EOPNOTSUPP;

- if (ca_keyid && !asymmetric_key_id_partial(cert->akid_skid, ca_keyid))
+ if (ca_keyid && !asymmetric_key_id_partial(sig->auth_ids[1], ca_keyid))
return -EPERM;

key = x509_request_asymmetric_key(trust_keyring,
- cert->akid_id, cert->akid_skid,
+ sig->auth_ids[0], sig->auth_ids[1],
false);
if (!IS_ERR(key)) {
if (!use_builtin_keys
@@ -292,8 +291,8 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
pr_devel("Cert Subject: %s\n", cert->subject);

if (!cert->pub->pkey_algo ||
- !cert->sig.pkey_algo ||
- !cert->sig.hash_algo) {
+ !cert->sig->pkey_algo ||
+ !cert->sig->hash_algo) {
ret = -ENOPKG;
goto error_free_cert;
}
@@ -301,15 +300,15 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
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);
pr_devel("Cert Signature: %s + %s\n",
- cert->sig.pkey_algo,
- cert->sig.hash_algo);
+ cert->sig->pkey_algo,
+ cert->sig->hash_algo);

cert->pub->id_type = "X509";

/* Check the signature on the key if it appears to be self-signed */
- if ((!cert->akid_skid && !cert->akid_id) ||
- asymmetric_key_id_same(cert->skid, cert->akid_skid) ||
- asymmetric_key_id_same(cert->id, cert->akid_id)) {
+ if ((!cert->sig->auth_ids[0] && !cert->sig->auth_ids[1]) ||
+ asymmetric_key_id_same(cert->skid, cert->sig->auth_ids[1]) ||
+ asymmetric_key_id_same(cert->id, cert->sig->auth_ids[0])) {
ret = x509_check_signature(cert->pub, cert); /* self-signed */
if (ret < 0)
goto error_free_cert;
@@ -353,6 +352,7 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
prep->payload.data[asym_subtype] = &public_key_subtype;
prep->payload.data[asym_key_ids] = kids;
prep->payload.data[asym_crypto] = cert->pub;
+ prep->payload.data[asym_auth] = cert->sig;
prep->description = desc;
prep->quotalen = 100;

@@ -360,6 +360,7 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
cert->pub = NULL;
cert->id = NULL;
cert->skid = NULL;
+ cert->sig = NULL;
desc = NULL;
ret = 0;

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