Do not create DSA keys without parameters by decoder

Reviewed-by: Paul Dale <pauli@openssl.org> Reviewed-by: Matt Caswell <matt@openssl.org>
openssl · Feb 7, 2023 · 604247b · 604247b
1 parent 9ac82e2
commit 604247b
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Showing 3 changed files with 28 additions and 1 deletion.
diff --git a/crypto/x509/x_pubkey.c b/crypto/x509/x_pubkey.c
@@ -748,6 +748,30 @@ DSA *d2i_DSA_PUBKEY(DSA **a, const unsigned char **pp, long length)
     return key;
 }
 
+/* Called from decoders; disallows provided DSA keys without parameters. */
+DSA *ossl_d2i_DSA_PUBKEY(DSA **a, const unsigned char **pp, long length)
+{
+    DSA *key = NULL;
+    const unsigned char *data;
+    const BIGNUM *p, *q, *g;
+
+    data = *pp;
+    key = d2i_DSA_PUBKEY(NULL, &data, length);
+    if (key == NULL)
+        return NULL;
+    DSA_get0_pqg(key, &p, &q, &g);
+    if (p == NULL || q == NULL || g == NULL) {
+        DSA_free(key);
+        return NULL;
+    }
+    *pp = data;
+    if (a != NULL) {
+        DSA_free(*a);
+        *a = key;
+    }
+    return key;
+}
+
 int i2d_DSA_PUBKEY(const DSA *a, unsigned char **pp)
 {
     EVP_PKEY *pktmp;

diff --git a/include/crypto/x509.h b/include/crypto/x509.h
@@ -339,6 +339,9 @@ void ossl_X509_PUBKEY_INTERNAL_free(X509_PUBKEY *xpub);
 
 RSA *ossl_d2i_RSA_PSS_PUBKEY(RSA **a, const unsigned char **pp, long length);
 int ossl_i2d_RSA_PSS_PUBKEY(const RSA *a, unsigned char **pp);
+# ifndef OPENSSL_NO_DSA
+DSA *ossl_d2i_DSA_PUBKEY(DSA **a, const unsigned char **pp, long length);
+# endif /* OPENSSL_NO_DSA */
 # ifndef OPENSSL_NO_DH
 DH *ossl_d2i_DH_PUBKEY(DH **a, const unsigned char **pp, long length);
 int ossl_i2d_DH_PUBKEY(const DH *a, unsigned char **pp);

diff --git a/providers/implementations/encode_decode/decode_der2key.c b/providers/implementations/encode_decode/decode_der2key.c
@@ -375,7 +375,7 @@ static void *dsa_d2i_PKCS8(void **key, const unsigned char **der, long der_len,
                              (key_from_pkcs8_t *)ossl_dsa_key_from_pkcs8);
 }
 
-# define dsa_d2i_PUBKEY                 (d2i_of_void *)d2i_DSA_PUBKEY
+# define dsa_d2i_PUBKEY                 (d2i_of_void *)ossl_d2i_DSA_PUBKEY
 # define dsa_free                       (free_key_fn *)DSA_free
 # define dsa_check                      NULL