Be more strict about BER and DER terminology.

bs_ber.c does not convert BER to DER.  It's a hack to convert a DER-like
encoding with one violation (indefinite form) to strict DER.  Rename
the functions to reflect this.

ok miod@ jsing@

2 files changed, 33 insertions, 28 deletions

diff --git a/lib/libssl/src/ssl/bs_ber.c b/lib/libssl/src/ssl/bs_ber.c
index 3d39def111b..1310d4a94ce 100644
--- a/lib/libssl/src/ssl/bs_ber.c
+++ b/lib/libssl/src/ssl/bs_ber.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bs_ber.c,v 1.5 2015/06/15 07:35:49 doug Exp $	*/
+/*	$OpenBSD: bs_ber.c,v 1.6 2015/06/16 06:37:58 doug Exp $	*/
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -29,7 +29,7 @@ static const unsigned kMaxDepth = 2048;
 
 /* Non-strict version that allows a relaxed DER with indefinite form. */
 static int
-cbs_nonstrict_get_any_asn1_element(CBS *cbs, CBS *out, unsigned *out_tag,
+cbs_nonstrict_get_any_asn1_element(CBS *cbs, CBS *out, unsigned int *out_tag,
     size_t *out_header_len)
 {
 	return cbs_get_any_asn1_element_internal(cbs, out,
@@ -37,13 +37,15 @@ cbs_nonstrict_get_any_asn1_element(CBS *cbs, CBS *out, unsigned *out_tag,
 }
 
 /*
- * cbs_find_ber walks an ASN.1 structure in |orig_in| and sets |*ber_found|
- * depending on whether an indefinite length element was found. The value of
- * |in| is not changed. It returns one on success (i.e. |*ber_found| was set)
- * and zero on error.
+ * cbs_find_indefinite walks an ASN.1 structure in |orig_in| and sets
+ * |*indefinite_found| depending on whether an indefinite length element was
+ * found. The value of |orig_in| is not modified.
+ *
+ * Returns one on success (i.e. |*indefinite_found| was set) and zero on error.
  */
 static int
-cbs_find_ber(CBS *orig_in, char *ber_found, unsigned depth)
+cbs_find_indefinite(const CBS *orig_in, char *indefinite_found,
+    unsigned int depth)
 {
 	CBS in;
 
@@ -51,7 +53,6 @@ cbs_find_ber(CBS *orig_in, char *ber_found, unsigned depth)
 		return 0;
 
 	CBS_init(&in, CBS_data(orig_in), CBS_len(orig_in));
-	*ber_found = 0;
 
 	while (CBS_len(&in) > 0) {
 		CBS contents;
@@ -65,16 +66,18 @@ cbs_find_ber(CBS *orig_in, char *ber_found, unsigned depth)
 		/* Indefinite form not allowed by DER. */
 		if (CBS_len(&contents) == header_len && header_len > 0 &&
 		    CBS_data(&contents)[header_len - 1] == 0x80) {
-			*ber_found = 1;
+			*indefinite_found = 1;
 			return 1;
 		}
 		if (tag & CBS_ASN1_CONSTRUCTED) {
 			if (!CBS_skip(&contents, header_len) ||
-			    !cbs_find_ber(&contents, ber_found, depth + 1))
+			    !cbs_find_indefinite(&contents, indefinite_found,
+			    depth + 1))
 				return 0;
 		}
 	}
 
+	*indefinite_found = 0;
 	return 1;
 }
 
@@ -104,7 +107,8 @@ is_eoc(size_t header_len, CBS *contents)
 }
 
 /*
- * cbs_convert_ber reads BER data from |in| and writes DER data to |out|. If
+ * cbs_convert_indefinite reads data with DER encoding (but relaxed to allow
+ * indefinite form) from |in| and writes definite form DER data to |out|. If
  * |squash_header| is set then the top-level of elements from |in| will not
  * have their headers written. This is used when concatenating the fragments of
  * an indefinite length, primitive value. If |looking_for_eoc| is set then any
@@ -112,8 +116,8 @@ is_eoc(size_t header_len, CBS *contents)
  * It returns one on success and zero on error.
  */
 static int
-cbs_convert_ber(CBS *in, CBB *out, char squash_header, char looking_for_eoc,
-    unsigned depth)
+cbs_convert_indefinite(CBS *in, CBB *out, char squash_header,
+    char looking_for_eoc, unsigned depth)
 {
 	if (depth > kMaxDepth)
 		return 0;
@@ -143,7 +147,7 @@ cbs_convert_ber(CBS *in, CBB *out, char squash_header, char looking_for_eoc,
 				 * with a concrete length prefix.
 				 *
 				 * If it's a something else then the contents
-				 * will be a series of BER elements of the same
+				 * will be a series of DER elements of the same
 				 * type which need to be concatenated.
 				 */
 				const char context_specific = (tag & 0xc0)
@@ -193,7 +197,7 @@ cbs_convert_ber(CBS *in, CBB *out, char squash_header, char looking_for_eoc,
 					out_contents = &out_contents_storage;
 				}
 
-				if (!cbs_convert_ber(in, out_contents,
+				if (!cbs_convert_indefinite(in, out_contents,
 				    squash_child_headers,
 				    1 /* looking for eoc */, depth + 1))
 					return 0;
@@ -216,7 +220,7 @@ cbs_convert_ber(CBS *in, CBB *out, char squash_header, char looking_for_eoc,
 			return 0;
 
 		if (tag & CBS_ASN1_CONSTRUCTED) {
-			if (!cbs_convert_ber(&contents, out_contents,
+			if (!cbs_convert_indefinite(&contents, out_contents,
 			    0 /* don't squash header */,
 			    0 /* not looking for eoc */, depth + 1))
 				return 0;
@@ -234,7 +238,7 @@ cbs_convert_ber(CBS *in, CBB *out, char squash_header, char looking_for_eoc,
 }
 
 int
-CBS_asn1_ber_to_der(CBS *in, uint8_t **out, size_t *out_len)
+CBS_asn1_indefinite_to_definite(CBS *in, uint8_t **out, size_t *out_len)
 {
 	CBB cbb;
 
@@ -244,7 +248,7 @@ CBS_asn1_ber_to_der(CBS *in, uint8_t **out, size_t *out_len)
 	 * return.
 	 */
 	char conversion_needed;
-	if (!cbs_find_ber(in, &conversion_needed, 0))
+	if (!cbs_find_indefinite(in, &conversion_needed, 0))
 		return 0;
 
 	if (!conversion_needed) {
@@ -254,7 +258,7 @@ CBS_asn1_ber_to_der(CBS *in, uint8_t **out, size_t *out_len)
 	}
 
 	CBB_init(&cbb, CBS_len(in));
-	if (!cbs_convert_ber(in, &cbb, 0, 0, 0)) {
+	if (!cbs_convert_indefinite(in, &cbb, 0, 0, 0)) {
 		CBB_cleanup(&cbb);
 		return 0;
 	}
diff --git a/lib/libssl/src/ssl/bytestring.h b/lib/libssl/src/ssl/bytestring.h
index ef824a0cead..07be6ddd50e 100644
--- a/lib/libssl/src/ssl/bytestring.h
+++ b/lib/libssl/src/ssl/bytestring.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bytestring.h,v 1.8 2015/06/16 06:11:39 doug Exp $	*/
+/*	$OpenBSD: bytestring.h,v 1.9 2015/06/16 06:37:58 doug Exp $	*/
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -464,22 +464,23 @@ int cbs_get_any_asn1_element_internal(CBS *cbs, CBS *out, unsigned *out_tag,
     size_t *out_header_len, int strict);
 
 /*
- * CBS_asn1_ber_to_der reads an ASN.1 structure from |in|. If it finds
- * indefinite-length elements then it attempts to convert the BER data to DER
- * and sets |*out| and |*out_length| to describe a malloced buffer containing
- * the DER data. Additionally, |*in| will be advanced over the ASN.1 data.
+ * CBS_asn1_indefinite_to_definite reads an ASN.1 structure from |in|. If it
+ * finds indefinite-length elements that otherwise appear to be valid DER, it
+ * attempts to convert the DER-like data to DER and sets |*out| and
+ * |*out_length| to describe a malloced buffer containing the DER data.
+ * Additionally, |*in| will be advanced over the ASN.1 data.
  *
  * If it doesn't find any indefinite-length elements then it sets |*out| to
  * NULL and |*in| is unmodified.
  *
- * A sufficiently complex ASN.1 structure will break this function because it's
- * not possible to generically convert BER to DER without knowledge of the
- * structure itself. However, this sufficies to handle the PKCS#7 and #12 output
+ * This is NOT a conversion from BER to DER.  There are many restrictions when
+ * dealing with DER data.  This is only concerned with one: indefinite vs.
+ * definite form. However, this suffices to handle the PKCS#7 and PKCS#12 output
  * from NSS.
  *
  * It returns one on success and zero otherwise.
  */
-int CBS_asn1_ber_to_der(CBS *in, uint8_t **out, size_t *out_len);
+int CBS_asn1_indefinite_to_definite(CBS *in, uint8_t **out, size_t *out_len);
 #endif /* LIBRESSL_INTERNAL */
 
 #if defined(__cplusplus)