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@

5 files changed, 84 insertions, 71 deletions

diff --git a/src/lib/libssl/bs_ber.c b/src/lib/libssl/bs_ber.c
index 3d39def111..1310d4a94c 100644
--- a/src/lib/libssl/bs_ber.c
+++ b/src/lib/libssl/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/src/lib/libssl/bytestring.h b/src/lib/libssl/bytestring.h
index ef824a0cea..07be6ddd50 100644
--- a/src/lib/libssl/bytestring.h
+++ b/src/lib/libssl/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)
diff --git a/src/lib/libssl/src/ssl/bs_ber.c b/src/lib/libssl/src/ssl/bs_ber.c
index 3d39def111..1310d4a94c 100644
--- a/src/lib/libssl/src/ssl/bs_ber.c
+++ b/src/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/src/lib/libssl/src/ssl/bytestring.h b/src/lib/libssl/src/ssl/bytestring.h
index ef824a0cea..07be6ddd50 100644
--- a/src/lib/libssl/src/ssl/bytestring.h
+++ b/src/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)
diff --git a/src/regress/lib/libssl/bytestring/bytestringtest.c b/src/regress/lib/libssl/bytestring/bytestringtest.c
index 7ae9397a35..05ca27e8b5 100644
--- a/src/regress/lib/libssl/bytestring/bytestringtest.c
+++ b/src/regress/lib/libssl/bytestring/bytestringtest.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bytestringtest.c,v 1.4 2015/04/25 15:28:47 doug Exp $ */
+/*      $OpenBSD: bytestringtest.c,v 1.5 2015/06/16 06:37:58 doug Exp $ */
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -484,23 +484,25 @@ err:
 }
 
 static int
-do_ber_convert(const char *name, const uint8_t *der_expected, size_t der_len,
-    const uint8_t *ber, size_t ber_len)
+do_indefinite_convert(const char *name, const uint8_t *definite_expected,
+    size_t definite_len, const uint8_t *indefinite, size_t indefinite_len)
 {
         CBS in;
         uint8_t *out = NULL;
         size_t out_len;
         int ret = 0;
 
-        CBS_init(&in, ber, ber_len);
-        if (!CBS_asn1_ber_to_der(&in, &out, &out_len)) {
-                fprintf(stderr, "%s: CBS_asn1_ber_to_der failed.\n", name);
+        CBS_init(&in, indefinite, indefinite_len);
+        if (!CBS_asn1_indefinite_to_definite(&in, &out, &out_len)) {
+                fprintf(stderr, "%s: CBS_asn1_indefinite_to_definite failed.\n",
+                    name);
                 goto end;
         }
 
         if (out == NULL) {
-                if (ber_len != der_len ||
-                    memcmp(der_expected, ber, ber_len) != 0) {
+                if (indefinite_len != definite_len ||
+                    memcmp(definite_expected, indefinite, indefinite_len)
+                    != 0) {
                         fprintf(stderr, "%s: incorrect unconverted result.\n",
                             name);
                         return 0;
@@ -509,7 +511,8 @@ do_ber_convert(const char *name, const uint8_t *der_expected, size_t der_len,
                 return 1;
         }
 
-        if (out_len != der_len || memcmp(out, der_expected, der_len) != 0) {
+        if (out_len != definite_len || memcmp(out, definite_expected,
+            definite_len) != 0) {
                 fprintf(stderr, "%s: incorrect converted result.\n", name);
                 goto end;
         }
@@ -522,7 +525,7 @@ end:
 }
 
 static int
-test_ber_convert(void)
+test_indefinite_convert(void)
 {
         static const uint8_t kSimpleBER[] = {0x01, 0x01, 0x00};
 
@@ -566,14 +569,14 @@ test_ber_convert(void)
             0x6e, 0x10, 0x9b, 0xb8, 0x02, 0x02, 0x07, 0xd0,
         };
 
-        return do_ber_convert("kSimpleBER", kSimpleBER, sizeof(kSimpleBER),
+        return do_indefinite_convert("kSimpleBER", kSimpleBER, sizeof(kSimpleBER),
             kSimpleBER, sizeof(kSimpleBER)) &&
-            do_ber_convert("kIndefBER", kIndefDER, sizeof(kIndefDER), kIndefBER,
+            do_indefinite_convert("kIndefBER", kIndefDER, sizeof(kIndefDER), kIndefBER,
             sizeof(kIndefBER)) &&
-            do_ber_convert("kOctetStringBER", kOctetStringDER,
+            do_indefinite_convert("kOctetStringBER", kOctetStringDER,
             sizeof(kOctetStringDER), kOctetStringBER,
             sizeof(kOctetStringBER)) &&
-            do_ber_convert("kNSSBER", kNSSDER, sizeof(kNSSDER), kNSSBER,
+            do_indefinite_convert("kNSSBER", kNSSDER, sizeof(kNSSDER), kNSSBER,
             sizeof(kNSSBER));
 }
 
@@ -682,7 +685,7 @@ main(void)
             !test_cbb_misuse() ||
             !test_cbb_prefixed() ||
             !test_cbb_asn1() ||
-            !test_ber_convert() ||
+            !test_indefinite_convert() ||
             !test_asn1_uint64() ||
             !test_get_optional_asn1_bool())
                 return 1;