Unwind ASN1_AFLG_BROKEN.

This is never used. Remove the logic so we can gradually simply the
legacy ASN.1 code.

Update-Note: Types using ASN1_BROKEN_SEQUENCE from openssl/asn1t.h will
fail to compile. This CL should not affect certificate parsing.

Change-Id: I06b61ae2656a657aed81cd467051a494155b0963
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/43887
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>

crypto/asn1/tasn_dec.c

@@ -174,7 +174,6 @@ static int asn1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in,
     unsigned char *wp = NULL;   /* BIG FAT WARNING! BREAKS CONST WHERE USED */
     unsigned char imphack = 0, oclass;
     char seq_eoc, seq_nolen, cst, isopt;
-    long tmplen;
     int i;
     int otag;
     int ret = 0;
@@ -373,7 +372,6 @@ static int asn1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in,
     case ASN1_ITYPE_NDEF_SEQUENCE:
     case ASN1_ITYPE_SEQUENCE:
         p = *in;
-        tmplen = len;
 
         /* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
         if (tag == -1) {
@@ -388,13 +386,8 @@ static int asn1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in,
             goto err;
         } else if (ret == -1)
             return -1;
-        if (aux && (aux->flags & ASN1_AFLG_BROKEN)) {
-            len = tmplen - (p - *in);
-            seq_nolen = 1;
-        }
         /* If indefinite we don't do a length check */
-        else
+        seq_nolen = seq_eoc;
-            seq_nolen = seq_eoc;
         if (!cst) {
             OPENSSL_PUT_ERROR(ASN1, ASN1_R_SEQUENCE_NOT_CONSTRUCTED);
             goto err;

include/openssl/asn1t.h

@@ -151,10 +151,6 @@ extern "C" {
 	static const ASN1_AUX tname##_aux = {NULL, 0, 0, cb, 0}; \
 	ASN1_SEQUENCE(tname)
 
-#define ASN1_BROKEN_SEQUENCE(tname) \
-	static const ASN1_AUX tname##_aux = {NULL, ASN1_AFLG_BROKEN, 0, 0, 0}; \
-	ASN1_SEQUENCE(tname)
-
 #define ASN1_SEQUENCE_ref(tname, cb) \
 	static const ASN1_AUX tname##_aux = {NULL, ASN1_AFLG_REFCOUNT, offsetof(tname, references), cb, 0}; \
 	ASN1_SEQUENCE(tname)
@@ -175,8 +171,6 @@ extern "C" {
 		#tname \
 	ASN1_ITEM_end(tname)
 
-#define ASN1_BROKEN_SEQUENCE_END(stname) ASN1_SEQUENCE_END_ref(stname, stname)
-
 #define ASN1_SEQUENCE_END_enc(stname, tname) ASN1_SEQUENCE_END_ref(stname, tname)
 
 #define ASN1_SEQUENCE_END_cb(stname, tname) ASN1_SEQUENCE_END_ref(stname, tname)
@@ -699,8 +693,6 @@ typedef struct ASN1_STREAM_ARG_st {
 #define ASN1_AFLG_REFCOUNT	1
 /* Save the encoding of structure (useful for signatures) */
 #define ASN1_AFLG_ENCODING	2
-/* The Sequence length is invalid */
-#define ASN1_AFLG_BROKEN	4
 
 /* operation values for asn1_cb */