Return shared OIDs when decoding.

When an OID is decoded see if it exists in the registered OID table
and if so return the shared OID instead of dynamically allocating
an ASN1_OBJECT.

Reviewed-by: Rich Salz <rsalz@openssl.org>

diff --git a/crypto/asn1/a_object.c b/crypto/asn1/a_object.c
index 44473dc1b38a4be1b13186ef68f2d8aa0009a272..80b50559785ef68aa3679107afe7e0cedabcdb89 100644 (file)
--- a/crypto/asn1/a_object.c
+++ b/crypto/asn1/a_object.c
@@ -271,7 +271,7 @@ ASN1_OBJECT *d2i_ASN1_OBJECT(ASN1_OBJECT **a, const unsigned char **pp,
 ASN1_OBJECT *c2i_ASN1_OBJECT(ASN1_OBJECT **a, const unsigned char **pp,
                              long len)
 {
-    ASN1_OBJECT *ret = NULL;
+    ASN1_OBJECT *ret = NULL, tobj;
     const unsigned char *p;
     unsigned char *data;
     int i, length;
@@ -288,6 +288,29 @@ ASN1_OBJECT *c2i_ASN1_OBJECT(ASN1_OBJECT **a, const unsigned char **pp,
     }
     /* Now 0 < len <= INT_MAX, so the cast is safe. */
     length = (int)len;
+    /*
+     * Try to lookup OID in table: these are all valid encodings so if we get
+     * a match we know the OID is valid.
+     */
+    tobj.nid = NID_undef;
+    tobj.data = p;
+    tobj.length = length;
+    tobj.flags = 0;
+    i = OBJ_obj2nid(&tobj);
+    if (i != NID_undef) {
+        /*
+         * Return shared registered OID object: this improves efficiency
+         * because we don't have to return a dynamically allocated OID
+         * and NID lookups can use the cached value.
+         */
+        ret = OBJ_nid2obj(i);
+        if (a) {
+            ASN1_OBJECT_free(*a);
+            *a = ret;
+        }
+        *pp += len;
+        return ret;
+    }
     for (i = 0; i < length; i++, p++) {
         if (*p == 0x80 && (!i || !(p[-1] & 0x80))) {
             ASN1err(ASN1_F_C2I_ASN1_OBJECT, ASN1_R_INVALID_OBJECT_ENCODING);