apps/{req,x509,ca}.c Make sure certs have SKID and AKID X.509 extensions by default

Fixes #13603

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/13658)

1 files changed, 46 insertions, 2 deletions

diff --git a/apps/lib/apps.c b/apps/lib/apps.c
index 457dac87bc..6ae35bac73 100644
--- a/apps/lib/apps.c
+++ b/apps/lib/apps.c
@@ -1982,12 +1982,41 @@ static int do_sign_init(EVP_MD_CTX *ctx, EVP_PKEY *pkey,
         && do_pkey_ctx_init(pkctx, sigopts);
 }
 
-/* Ensure RFC 5280 compliance and then sign the certificate info */
+static int adapt_keyid_ext(X509 *cert, X509V3_CTX *ext_ctx,
+                           const char *name, const char *value, int add_default)
+{
+    const STACK_OF(X509_EXTENSION) *exts = X509_get0_extensions(cert);
+    X509_EXTENSION *new_ext = X509V3_EXT_nconf(NULL, ext_ctx, name, value);
+    int idx, rv = 0;
+
+    if (new_ext == NULL)
+        return rv;
+
+    idx = X509v3_get_ext_by_OBJ(exts, X509_EXTENSION_get_object(new_ext), -1);
+    if (idx >= 0) {
+        X509_EXTENSION *found_ext = X509v3_get_ext(exts, idx);
+        ASN1_OCTET_STRING *data = X509_EXTENSION_get_data(found_ext);
+        int disabled = ASN1_STRING_length(data) <= 2; /* config said "none" */
+
+        if (disabled) {
+            X509_delete_ext(cert, idx);
+            X509_EXTENSION_free(found_ext);
+        } /* else keep existing key identifier, which might be outdated */
+        rv = 1;
+    } else  {
+        rv = !add_default || X509_add_ext(cert, new_ext, -1);
+    }
+    X509_EXTENSION_free(new_ext);
+    return rv;
+}
+
+/* Ensure RFC 5280 compliance, adapt keyIDs as needed, and sign the cert info */
 int do_X509_sign(X509 *cert, EVP_PKEY *pkey, const EVP_MD *md,
-                 STACK_OF(OPENSSL_STRING) *sigopts)
+                 STACK_OF(OPENSSL_STRING) *sigopts, X509V3_CTX *ext_ctx)
 {
     const STACK_OF(X509_EXTENSION) *exts = X509_get0_extensions(cert);
     EVP_MD_CTX *mctx = EVP_MD_CTX_new();
+    int self_sign;
     int rv = 0;
 
     if (sk_X509_EXTENSION_num(exts /* may be NULL */) > 0) {
@@ -1995,6 +2024,21 @@ int do_X509_sign(X509 *cert, EVP_PKEY *pkey, const EVP_MD *md,
         if (!X509_set_version(cert, 2)) /* Make sure cert is X509 v3 */
             goto end;
 
+        /*
+         * Add default SKID before such that default AKID can make use of it
+         * in case the certificate is self-signed
+         */
+        /* Prevent X509_V_ERR_MISSING_SUBJECT_KEY_IDENTIFIER */
+        if (!adapt_keyid_ext(cert, ext_ctx, "subjectKeyIdentifier", "hash", 1))
+            goto end;
+        /* Prevent X509_V_ERR_MISSING_AUTHORITY_KEY_IDENTIFIER */
+        ERR_set_mark();
+        self_sign = X509_check_private_key(cert, pkey);
+        ERR_pop_to_mark();
+        if (!adapt_keyid_ext(cert, ext_ctx, "authorityKeyIdentifier",
+                             "keyid, issuer", !self_sign))
+            goto end;
+
         /* TODO any further measures for ensuring default RFC 5280 compliance */
     }