Rewrite ASN1_OBJECT content to ascii/text conversion.

Rewrite the ASN1_OBJECT content to ascii/text conversion code using CBB and
CBS. Currently there is a strange split with i2t_ASN1_OBJECT() calling
OBJ_obj2txt() which implements the conversion, while OBJ_txt2obj() calls
back into the misnamed a2d_ASN1_OBJECT() function. Move the conversion
code into asn1/a_object.c and have OBJ_txt2obj() call that instead.

ok inoguchi@ tb@

2 files changed, 181 insertions, 25 deletions

diff --git a/src/lib/libcrypto/asn1/a_object.c b/src/lib/libcrypto/asn1/a_object.c
index 1407f7df1c..f26026e6aa 100644
--- a/src/lib/libcrypto/asn1/a_object.c
+++ b/src/lib/libcrypto/asn1/a_object.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: a_object.c,v 1.37 2022/01/07 11:13:54 tb Exp $ */
+/* $OpenBSD: a_object.c,v 1.38 2022/03/02 11:28:00 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -270,37 +270,190 @@ a2d_ASN1_OBJECT(unsigned char *out, int olen, const char *buf, int num)
         return (0);
 }
 
+static int
+oid_parse_arc(CBS *cbs, uint64_t *out_arc)
+{
+        uint64_t arc = 0;
+        uint8_t val;
+
+        do {
+                if (!CBS_get_u8(cbs, &val))
+                        return 0;
+                if (arc == 0 && val == 0x80)
+                        return 0;
+                if (arc > (UINT64_MAX >> 7))
+                        return 0;
+                arc = (arc << 7) | (val & 0x7f);
+        } while (val & 0x80);
+
+        *out_arc = arc;
+
+        return 1;
+}
+
+static int
+oid_add_arc_txt(CBB *cbb, uint64_t arc, int first)
+{
+        const char *fmt = ".%llu";
+        char s[22]; /* Digits in decimal representation of 2^64-1, plus '.' and NUL. */
+        int n;
+
+        if (first)
+                fmt = "%llu";
+        n = snprintf(s, sizeof(s), fmt, (unsigned long long)arc);
+        if (n < 0 || (size_t)n >= sizeof(s))
+                return 0;
+        if (!CBB_add_bytes(cbb, s, n))
+                return 0;
+
+        return 1;
+}
+
+static int
+c2a_ASN1_OBJECT(CBS *cbs, CBB *cbb)
+{
+        uint64_t arc, si1, si2;
+
+        /*
+         * X.690 section 8.19 - the first two subidentifiers are encoded as
+         * (x * 40) + y, with x being limited to [0,1,2].
+         */
+        if (!oid_parse_arc(cbs, &arc))
+                return 0;
+        if ((si1 = arc / 40) > 2)
+                si1 = 2;
+        si2 = arc - si1 * 40;
+
+        if (!oid_add_arc_txt(cbb, si1, 1))
+                return 0;
+        if (!oid_add_arc_txt(cbb, si2, 0))
+                return 0;
+
+        while (CBS_len(cbs) > 0) {
+                if (!oid_parse_arc(cbs, &arc))
+                        return 0;
+                if (!oid_add_arc_txt(cbb, arc, 0))
+                        return 0;
+        }
+
+        /* NUL terminate. */
+        if (!CBB_add_u8(cbb, 0))
+                return 0;
+
+        return 1;
+}
+
+static int
+i2t_ASN1_OBJECT_oid(const ASN1_OBJECT *aobj, CBB *cbb)
+{
+        CBS cbs;
+
+        CBS_init(&cbs, aobj->data, aobj->length);
+
+        return c2a_ASN1_OBJECT(&cbs, cbb);
+}
+
+static int
+i2t_ASN1_OBJECT_name(const ASN1_OBJECT *aobj, CBB *cbb, const char **out_name)
+{
+        const char *name;
+        int nid;
+
+        if ((nid = OBJ_obj2nid(aobj)) == NID_undef)
+                return 0;
+
+        if ((name = OBJ_nid2ln(nid)) == NULL)
+                name = OBJ_nid2sn(nid);
+        if (name == NULL)
+                return 0;
+
+        *out_name = name;
+
+        if (!CBB_add_bytes(cbb, name, strlen(name)))
+                return 0;
+
+        /* NUL terminate. */
+        if (!CBB_add_u8(cbb, 0))
+                return 0;
+
+        return 1;
+}
+
+static int
+i2t_ASN1_OBJECT_cbb(const ASN1_OBJECT *aobj, CBB *cbb, int no_name)
+{
+        const char *name;
+
+        if (!no_name) {
+                if (i2t_ASN1_OBJECT_name(aobj, cbb, &name))
+                        return 1;
+                if (name != NULL)
+                        return 0;
+        }
+        return i2t_ASN1_OBJECT_oid(aobj, cbb);
+}
+
+int
+i2t_ASN1_OBJECT_internal(const ASN1_OBJECT *aobj, char *buf, int buf_len, int no_name)
+{
+        uint8_t *data = NULL;
+        size_t data_len;
+        CBB cbb;
+        int ret = 0;
+
+        if (buf_len < 0)
+                return 0;
+        if (buf_len > 0)
+                buf[0] = '\0';
+
+        if (!CBB_init(&cbb, 0))
+                goto err;
+        if (!i2t_ASN1_OBJECT_cbb(aobj, &cbb, no_name))
+                goto err;
+        if (!CBB_finish(&cbb, &data, &data_len))
+                goto err;
+
+        ret = strlcpy(buf, data, buf_len);
+ err:
+        CBB_cleanup(&cbb);
+        free(data);
+
+        return ret;
+}
+
 int
-i2t_ASN1_OBJECT(char *buf, int buf_len, const ASN1_OBJECT *a)
+i2t_ASN1_OBJECT(char *buf, int buf_len, const ASN1_OBJECT *aobj)
 {
-        return OBJ_obj2txt(buf, buf_len, a, 0);
+        return i2t_ASN1_OBJECT_internal(aobj, buf, buf_len, 0);
 }
 
 int
-i2a_ASN1_OBJECT(BIO *bp, const ASN1_OBJECT *a)
+i2a_ASN1_OBJECT(BIO *bp, const ASN1_OBJECT *aobj)
 {
-        char *tmp = NULL;
-        size_t tlen = 256;
-        int i = -1;
+        uint8_t *data = NULL;
+        size_t data_len;
+        CBB cbb;
+        int ret = -1;
 
-        if ((a == NULL) || (a->data == NULL))
-                return(BIO_write(bp, "NULL", 4));
-        if ((tmp = malloc(tlen)) == NULL)
-                return -1;
-        i = i2t_ASN1_OBJECT(tmp, tlen, a);
-        if (i > (int)(tlen - 1)) {
-                freezero(tmp, tlen);
-                if ((tmp = malloc(i + 1)) == NULL)
-                        return -1;
-                tlen = i + 1;
-                i = i2t_ASN1_OBJECT(tmp, tlen, a);
+        if (aobj == NULL || aobj->data == NULL)
+                return BIO_write(bp, "NULL", 4);
+
+        if (!CBB_init(&cbb, 0))
+                goto err;
+        if (!i2t_ASN1_OBJECT_cbb(aobj, &cbb, 0)) {
+                ret = BIO_write(bp, "<INVALID>", 9);
+                goto err;
         }
-        if (i <= 0)
-                i = BIO_write(bp, "<INVALID>", 9);
-        else
-                i = BIO_write(bp, tmp, i);
-        freezero(tmp, tlen);
-        return (i);
+        if (!CBB_finish(&cbb, &data, &data_len))
+                goto err;
+                
+        ret = BIO_write(bp, data, data_len);
+
+ err:
+        CBB_cleanup(&cbb);
+        free(data);
+
+        return ret;
 }
 
 ASN1_OBJECT *
diff --git a/src/lib/libcrypto/asn1/asn1_locl.h b/src/lib/libcrypto/asn1/asn1_locl.h
index 7d34d7c17a..bb6a9fc91a 100644
--- a/src/lib/libcrypto/asn1/asn1_locl.h
+++ b/src/lib/libcrypto/asn1/asn1_locl.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: asn1_locl.h,v 1.20 2022/01/14 08:53:53 tb Exp $ */
+/* $OpenBSD: asn1_locl.h,v 1.21 2022/03/02 11:28:00 jsing Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -201,4 +201,7 @@ int asn1_get_object_cbs(CBS *cbs, int der_mode, uint8_t *out_class,
 
 int asn1_tag2charwidth(int tag);
 
+int i2t_ASN1_OBJECT_internal(const ASN1_OBJECT *aobj, char *buf, int buf_len,
+    int no_name);
+
 __END_HIDDEN_DECLS