Rewrite ascii/text to ASN.1 object conversion.

Rewrite the ascii/text to ASN.1 object conversion code using CBB/CBS,
while also addressing some of the bizarre behaviour (such as allowing
mixed separators and treating '..' as a zero value).

ok inoguchi@ tb@

1 files changed, 167 insertions, 121 deletions

diff --git a/src/lib/libcrypto/asn1/a_object.c b/src/lib/libcrypto/asn1/a_object.c
index 120437bf10..0061ccb880 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 1.41 2022/03/15 18:47:22 jsing Exp $ */
+/* $OpenBSD: a_object.c,v 1.42 2022/03/19 17:35:52 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -62,7 +62,6 @@
 
 #include <openssl/asn1.h>
 #include <openssl/asn1t.h>
-#include <openssl/bn.h>
 #include <openssl/err.h>
 #include <openssl/buffer.h>
 #include <openssl/objects.h>
@@ -146,128 +145,25 @@ i2d_ASN1_OBJECT(const ASN1_OBJECT *a, unsigned char **pp)
         return (objsize);
 }
 
-int
-a2d_ASN1_OBJECT(unsigned char *out, int olen, const char *buf, int num)
+static int
+oid_add_arc(CBB *cbb, uint64_t arc)
 {
-        int i, first, len = 0, c, use_bn;
-        char ftmp[24], *tmp = ftmp;
-        int tmpsize = sizeof ftmp;
-        const char *p;
-        unsigned long l;
-        BIGNUM *bl = NULL;
-
-        if (num == 0)
-                return (0);
-        else if (num == -1)
-                num = strlen(buf);
-
-        p = buf;
-        c = *(p++);
-        num--;
-        if ((c >= '0') && (c <= '2')) {
-                first= c-'0';
-        } else {
-                ASN1error(ASN1_R_FIRST_NUM_TOO_LARGE);
-                goto err;
-        }
-
-        if (num <= 0) {
-                ASN1error(ASN1_R_MISSING_SECOND_NUMBER);
-                goto err;
-        }
-        c = *(p++);
-        num--;
-        for (;;) {
-                if (num <= 0)
-                        break;
-                if ((c != '.') && (c != ' ')) {
-                        ASN1error(ASN1_R_INVALID_SEPARATOR);
-                        goto err;
-                }
-                l = 0;
-                use_bn = 0;
-                for (;;) {
-                        if (num <= 0)
-                                break;
-                        num--;
-                        c = *(p++);
-                        if ((c == ' ') || (c == '.'))
-                                break;
-                        if ((c < '0') || (c > '9')) {
-                                ASN1error(ASN1_R_INVALID_DIGIT);
-                                goto err;
-                        }
-                        if (!use_bn && l >= ((ULONG_MAX - 80) / 10L)) {
-                                use_bn = 1;
-                                if (!bl)
-                                        bl = BN_new();
-                                if (!bl || !BN_set_word(bl, l))
-                                        goto err;
-                        }
-                        if (use_bn) {
-                                if (!BN_mul_word(bl, 10L) ||
-                                    !BN_add_word(bl, c-'0'))
-                                        goto err;
-                        } else
-                                l = l * 10L + (long)(c - '0');
-                }
-                if (len == 0) {
-                        if ((first < 2) && (l >= 40)) {
-                                ASN1error(ASN1_R_SECOND_NUMBER_TOO_LARGE);
-                                goto err;
-                        }
-                        if (use_bn) {
-                                if (!BN_add_word(bl, first * 40))
-                                        goto err;
-                        } else
-                                l += (long)first * 40;
-                }
-                i = 0;
-                if (use_bn) {
-                        int blsize;
-                        blsize = BN_num_bits(bl);
-                        blsize = (blsize + 6) / 7;
-                        if (blsize > tmpsize) {
-                                if (tmp != ftmp)
-                                        free(tmp);
-                                tmpsize = blsize + 32;
-                                tmp = malloc(tmpsize);
-                                if (!tmp)
-                                        goto err;
-                        }
-                        while (blsize--)
-                                tmp[i++] = (unsigned char)BN_div_word(bl, 0x80L);
-                } else {
-
-                        for (;;) {
-                                tmp[i++] = (unsigned char)l & 0x7f;
-                                l >>= 7L;
-                                if (l == 0L)
-                                        break;
-                        }
-
-                }
-                if (out != NULL) {
-                        if (len + i > olen) {
-                                ASN1error(ASN1_R_BUFFER_TOO_SMALL);
-                                goto err;
-                        }
-                        while (--i > 0)
-                                out[len++] = tmp[i]|0x80;
-                        out[len++] = tmp[0];
-                } else
-                        len += i;
+        int started = 0;
+        uint8_t val;
+        int i;
+
+        for (i = (sizeof(arc) * 8) / 7; i >= 0; i--) {
+                val = (arc >> (i * 7)) & 0x7f;
+                if (!started && i != 0 && val == 0)
+                        continue;
+                if (i > 0)
+                        val |= 0x80;
+                if (!CBB_add_u8(cbb, val))
+                        return 0;
+                started = 1;
         }
-        if (tmp != ftmp)
-                free(tmp);
-        BN_free(bl);
-        return (len);
 
- err:
-        if (tmp != ftmp)
-                free(tmp);
-        BN_free(bl);
-        return (0);
+        return 1;
 }
 
 static int
@@ -310,6 +206,111 @@ oid_add_arc_txt(CBB *cbb, uint64_t arc, int first)
 }
 
 static int
+oid_parse_arc_txt(CBS *cbs, uint64_t *out_arc, char *separator, int first)
+{
+        uint64_t arc = 0;
+        int digits = 0;
+        uint8_t val;
+
+        if (!first) {
+                if (!CBS_get_u8(cbs, &val))
+                        return 0;
+                if ((*separator == 0 && val != '.' && val != ' ') ||
+                    (*separator != 0 && val != *separator)) {
+                        ASN1error(ASN1_R_INVALID_SEPARATOR);
+                        return 0;
+                }
+                *separator = val;
+        }
+
+        while (CBS_len(cbs) > 0) {
+                if (!CBS_peek_u8(cbs, &val))
+                        return 0;
+                if (val == '.' || val == ' ')
+                        break;
+
+                if (!CBS_get_u8(cbs, &val))
+                        return 0;
+                if (val < '0' || val > '9') {
+                        /* For the first arc we treat this as the separator. */
+                        if (first) {
+                                ASN1error(ASN1_R_INVALID_SEPARATOR);
+                                return 0;
+                        }
+                        ASN1error(ASN1_R_INVALID_DIGIT);
+                        return 0;
+                }
+                val -= '0';
+
+                if (digits > 0 && arc == 0 && val == 0) {
+                        ASN1error(ASN1_R_INVALID_NUMBER);
+                        return 0;
+                }
+                digits++;
+
+                if (arc > UINT64_MAX / 10) {
+                        ASN1error(ASN1_R_TOO_LONG);
+                        return 0;
+                }
+                arc = arc * 10 + val;
+        }
+
+        if (digits < 1) {
+                ASN1error(ASN1_R_INVALID_NUMBER);
+                return 0;
+        }
+
+        *out_arc = arc;
+
+        return 1;
+}
+
+static int
+a2c_ASN1_OBJECT_internal(CBB *cbb, CBS *cbs)
+{
+        uint64_t arc, si1, si2;
+        char separator = 0;
+
+        if (!oid_parse_arc_txt(cbs, &si1, &separator, 1))
+                return 0;
+
+        if (CBS_len(cbs) == 0) {
+                ASN1error(ASN1_R_MISSING_SECOND_NUMBER);
+                return 0;
+        }
+
+        if (!oid_parse_arc_txt(cbs, &si2, &separator, 0))
+                return 0;
+
+        /*
+         * X.690 section 8.19 - the first two subidentifiers are encoded as
+         * (x * 40) + y, with x being limited to [0,1,2]. The second
+         * subidentifier cannot exceed 39 for x < 2.
+         */
+        if (si1 > 2) {
+                ASN1error(ASN1_R_FIRST_NUM_TOO_LARGE);
+                return 0;
+        }
+        if ((si1 < 2 && si2 >= 40) || si2 > UINT64_MAX - si1 * 40) {
+                ASN1error(ASN1_R_SECOND_NUMBER_TOO_LARGE);
+                return 0;
+        }
+        arc = si1 * 40 + si2;
+
+        if (!oid_add_arc(cbb, arc))
+                return 0;
+
+        while (CBS_len(cbs) > 0) {
+                if (!oid_parse_arc_txt(cbs, &arc, &separator, 0))
+                        return 0;
+                if (!oid_add_arc(cbb, arc))
+                        return 0;
+        }
+
+        return 1;
+}
+
+static int
 c2a_ASN1_OBJECT(CBS *cbs, CBB *cbb)
 {
         uint64_t arc, si1, si2;
@@ -343,6 +344,51 @@ c2a_ASN1_OBJECT(CBS *cbs, CBB *cbb)
         return 1;
 }
 
+int
+a2d_ASN1_OBJECT(unsigned char *out, int out_len, const char *in, int in_len)
+{
+        uint8_t *data = NULL;
+        size_t data_len;
+        CBS cbs;
+        CBB cbb;
+        int ret = 0;
+
+        memset(&cbb, 0, sizeof(cbb));
+
+        if (in_len == -1)
+                in_len = strlen(in);
+        if (in_len <= 0)
+                goto err;
+
+        CBS_init(&cbs, in, in_len);
+
+        if (!CBB_init(&cbb, 0))
+                goto err;
+        if (!a2c_ASN1_OBJECT_internal(&cbb, &cbs))
+                goto err;
+        if (!CBB_finish(&cbb, &data, &data_len))
+                goto err;
+
+        if (data_len > INT_MAX)
+                goto err;
+
+        if (out != NULL) {
+                if (out_len <= 0 || (size_t)out_len < data_len) {
+                        ASN1error(ASN1_R_BUFFER_TOO_SMALL);
+                        goto err;
+                }
+                memcpy(out, data, data_len);
+        }
+
+        ret = (int)data_len;
+
+ err:
+        CBB_cleanup(&cbb);
+        free(data);
+
+        return ret;
+}
+
 static int
 i2t_ASN1_OBJECT_oid(const ASN1_OBJECT *aobj, CBB *cbb)
 {