PKCS#7: Make the signature a pointer rather than embedding it

Point to the public_key_signature struct from the pkcs7_signed_info struct
rather than embedding it.  This makes the code consistent with the X.509
signature handling and makes it possible to have a common cleanup function.

We also save a copy of the digest in the signature without sharing the
memory with the crypto layer metadata.

Signed-off-by: David Howells <dhowells@redhat.com>

diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c
index 40de03f..8357016 100644 (file)
--- a/crypto/asymmetric_keys/pkcs7_parser.c
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -44,9 +44,7 @@ struct pkcs7_parse_context {
 static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo)
 {
        if (sinfo) {
-               kfree(sinfo->sig.s);
-               kfree(sinfo->sig.digest);
-               kfree(sinfo->signing_cert_id);
+               public_key_signature_free(sinfo->sig);
                kfree(sinfo);
        }
 }
@@ -125,6 +123,10 @@ struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen)
        ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
        if (!ctx->sinfo)
                goto out_no_sinfo;
+       ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature),
+                                 GFP_KERNEL);
+       if (!ctx->sinfo->sig)
+               goto out_no_sig;
 
        ctx->data = (unsigned long)data;
        ctx->ppcerts = &ctx->certs;
@@ -150,6 +152,7 @@ out:
                ctx->certs = cert->next;
                x509_free_certificate(cert);
        }
+out_no_sig:
        pkcs7_free_signed_info(ctx->sinfo);
 out_no_sinfo:
        pkcs7_free_message(ctx->msg);
@@ -218,25 +221,26 @@ int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen,
 
        switch (ctx->last_oid) {
        case OID_md4:
-               ctx->sinfo->sig.hash_algo = "md4";
+               ctx->sinfo->sig->hash_algo = "md4";
                break;
        case OID_md5:
-               ctx->sinfo->sig.hash_algo = "md5";
+               ctx->sinfo->sig->hash_algo = "md5";
                break;
        case OID_sha1:
-               ctx->sinfo->sig.hash_algo = "sha1";
+               ctx->sinfo->sig->hash_algo = "sha1";
                break;
        case OID_sha256:
-               ctx->sinfo->sig.hash_algo = "sha256";
+               ctx->sinfo->sig->hash_algo = "sha256";
                break;
        case OID_sha384:
-               ctx->sinfo->sig.hash_algo = "sha384";
+               ctx->sinfo->sig->hash_algo = "sha384";
                break;
        case OID_sha512:
-               ctx->sinfo->sig.hash_algo = "sha512";
+               ctx->sinfo->sig->hash_algo = "sha512";
                break;
        case OID_sha224:
-               ctx->sinfo->sig.hash_algo = "sha224";
+               ctx->sinfo->sig->hash_algo = "sha224";
+               break;
        default:
                printk("Unsupported digest algo: %u\n", ctx->last_oid);
                return -ENOPKG;
@@ -255,7 +259,7 @@ int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen,
 
        switch (ctx->last_oid) {
        case OID_rsaEncryption:
-               ctx->sinfo->sig.pkey_algo = "rsa";
+               ctx->sinfo->sig->pkey_algo = "rsa";
                break;
        default:
                printk("Unsupported pkey algo: %u\n", ctx->last_oid);
@@ -615,11 +619,11 @@ int pkcs7_sig_note_signature(void *context, size_t hdrlen,
 {
        struct pkcs7_parse_context *ctx = context;
 
-       ctx->sinfo->sig.s = kmemdup(value, vlen, GFP_KERNEL);
-       if (!ctx->sinfo->sig.s)
+       ctx->sinfo->sig->s = kmemdup(value, vlen, GFP_KERNEL);
+       if (!ctx->sinfo->sig->s)
                return -ENOMEM;
 
-       ctx->sinfo->sig.s_size = vlen;
+       ctx->sinfo->sig->s_size = vlen;
        return 0;
 }
 
@@ -655,12 +659,16 @@ int pkcs7_note_signed_info(void *context, size_t hdrlen,
 
        pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data);
 
-       sinfo->signing_cert_id = kid;
+       sinfo->sig->auth_ids[0] = kid;
        sinfo->index = ++ctx->sinfo_index;
        *ctx->ppsinfo = sinfo;
        ctx->ppsinfo = &sinfo->next;
        ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
        if (!ctx->sinfo)
                return -ENOMEM;
+       ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature),
+                                 GFP_KERNEL);
+       if (!ctx->sinfo->sig)
+               return -ENOMEM;
        return 0;
 }

diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h
index a66b19e..d5eec31 100644 (file)
--- a/crypto/asymmetric_keys/pkcs7_parser.h
+++ b/crypto/asymmetric_keys/pkcs7_parser.h
@@ -41,19 +41,17 @@ struct pkcs7_signed_info {
 #define        sinfo_has_ms_statement_type     5
        time64_t        signing_time;
 
-       /* Issuing cert serial number and issuer's name [PKCS#7 or CMS ver 1]
-        * or issuing cert's SKID [CMS ver 3].
-        */
-       struct asymmetric_key_id *signing_cert_id;
-
        /* Message signature.
         *
         * This contains the generated digest of _either_ the Content Data or
         * the Authenticated Attributes [RFC2315 9.3].  If the latter, one of
         * the attributes contains the digest of the the Content Data within
         * it.
+        *
+        * THis also contains the issuing cert serial number and issuer's name
+        * [PKCS#7 or CMS ver 1] or issuing cert's SKID [CMS ver 3].
         */
-       struct public_key_signature sig;
+       struct public_key_signature *sig;
 };
 
 struct pkcs7_message {

diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index ed81282..b9a5487 100644 (file)
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -27,7 +27,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
                                    struct pkcs7_signed_info *sinfo,
                                    struct key *trust_keyring)
 {
-       struct public_key_signature *sig = &sinfo->sig;
+       struct public_key_signature *sig = sinfo->sig;
        struct x509_certificate *x509, *last = NULL, *p;
        struct key *key;
        bool trusted;
@@ -105,7 +105,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
         * the signed info directly.
         */
        key = x509_request_asymmetric_key(trust_keyring,
-                                         sinfo->signing_cert_id,
+                                         sinfo->sig->auth_ids[0],
                                          NULL,
                                          false);
        if (!IS_ERR(key)) {

diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index d8d8d23..1426f03 100644 (file)
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -25,34 +25,36 @@
 static int pkcs7_digest(struct pkcs7_message *pkcs7,
                        struct pkcs7_signed_info *sinfo)
 {
+       struct public_key_signature *sig = sinfo->sig;
        struct crypto_shash *tfm;
        struct shash_desc *desc;
-       size_t digest_size, desc_size;
-       void *digest;
+       size_t desc_size;
        int ret;
 
-       kenter(",%u,%s", sinfo->index, sinfo->sig.hash_algo);
+       kenter(",%u,%s", sinfo->index, sinfo->sig->hash_algo);
 
-       if (!sinfo->sig.hash_algo)
+       if (!sinfo->sig->hash_algo)
                return -ENOPKG;
 
        /* Allocate the hashing algorithm we're going to need and find out how
         * big the hash operational data will be.
         */
-       tfm = crypto_alloc_shash(sinfo->sig.hash_algo, 0, 0);
+       tfm = crypto_alloc_shash(sinfo->sig->hash_algo, 0, 0);
        if (IS_ERR(tfm))
                return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm);
 
        desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
-       sinfo->sig.digest_size = digest_size = crypto_shash_digestsize(tfm);
+       sig->digest_size = crypto_shash_digestsize(tfm);
 
        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_no_desc;
+
+       desc = kzalloc(desc_size, GFP_KERNEL);
+       if (!desc)
                goto error_no_desc;
 
-       desc = PTR_ALIGN(digest + digest_size, __alignof__(*desc));
        desc->tfm   = tfm;
        desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
@@ -60,10 +62,11 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
        ret = crypto_shash_init(desc);
        if (ret < 0)
                goto error;
-       ret = crypto_shash_finup(desc, pkcs7->data, pkcs7->data_len, digest);
+       ret = crypto_shash_finup(desc, pkcs7->data, pkcs7->data_len,
+                                sig->digest);
        if (ret < 0)
                goto error;
-       pr_devel("MsgDigest = [%*ph]\n", 8, digest);
+       pr_devel("MsgDigest = [%*ph]\n", 8, sig->digest);
 
        /* However, if there are authenticated attributes, there must be a
         * message digest attribute amongst them which corresponds to the
@@ -78,14 +81,15 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
                        goto error;
                }
 
-               if (sinfo->msgdigest_len != sinfo->sig.digest_size) {
+               if (sinfo->msgdigest_len != sig->digest_size) {
                        pr_debug("Sig %u: Invalid digest size (%u)\n",
                                 sinfo->index, sinfo->msgdigest_len);
                        ret = -EBADMSG;
                        goto error;
                }
 
-               if (memcmp(digest, sinfo->msgdigest, sinfo->msgdigest_len) != 0) {
+               if (memcmp(sig->digest, sinfo->msgdigest,
+                          sinfo->msgdigest_len) != 0) {
                        pr_debug("Sig %u: Message digest doesn't match\n",
                                 sinfo->index);
                        ret = -EKEYREJECTED;
@@ -97,7 +101,7 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
                 * convert the attributes from a CONT.0 into a SET before we
                 * hash it.
                 */
-               memset(digest, 0, sinfo->sig.digest_size);
+               memset(sig->digest, 0, sig->digest_size);
 
                ret = crypto_shash_init(desc);
                if (ret < 0)
@@ -107,17 +111,14 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
                if (ret < 0)
                        goto error;
                ret = crypto_shash_finup(desc, sinfo->authattrs,
-                                        sinfo->authattrs_len, digest);
+                                        sinfo->authattrs_len, sig->digest);
                if (ret < 0)
                        goto error;
-               pr_devel("AADigest = [%*ph]\n", 8, digest);
+               pr_devel("AADigest = [%*ph]\n", 8, sig->digest);
        }
 
-       sinfo->sig.digest = digest;
-       digest = NULL;
-
 error:
-       kfree(digest);
+       kfree(desc);
 error_no_desc:
        crypto_free_shash(tfm);
        kleave(" = %d", ret);
@@ -144,12 +145,12 @@ static int pkcs7_find_key(struct pkcs7_message *pkcs7,
                 * PKCS#7 message - but I can't be 100% sure of that.  It's
                 * possible this will need element-by-element comparison.
                 */
-               if (!asymmetric_key_id_same(x509->id, sinfo->signing_cert_id))
+               if (!asymmetric_key_id_same(x509->id, sinfo->sig->auth_ids[0]))
                        continue;
                pr_devel("Sig %u: Found cert serial match X.509[%u]\n",
                         sinfo->index, certix);
 
-               if (x509->pub->pkey_algo != sinfo->sig.pkey_algo) {
+               if (x509->pub->pkey_algo != sinfo->sig->pkey_algo) {
                        pr_warn("Sig %u: X.509 algo and PKCS#7 sig algo don't match\n",
                                sinfo->index);
                        continue;
@@ -164,7 +165,7 @@ static int pkcs7_find_key(struct pkcs7_message *pkcs7,
         */
        pr_debug("Sig %u: Issuing X.509 cert not found (#%*phN)\n",
                 sinfo->index,
-                sinfo->signing_cert_id->len, sinfo->signing_cert_id->data);
+                sinfo->sig->auth_ids[0]->len, sinfo->sig->auth_ids[0]->data);
        return 0;
 }
 
@@ -334,7 +335,7 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
        }
 
        /* Verify the PKCS#7 binary against the key */
-       ret = public_key_verify_signature(sinfo->signer->pub, &sinfo->sig);
+       ret = public_key_verify_signature(sinfo->signer->pub, sinfo->sig);
        if (ret < 0)
                return ret;