Free up ASN.1 structures at top level only.

When a decoding error in ASN.1 occurs only free up the partial structure
at the top level. This simplifies embedded handling and fixes freeing
up of structures when presented with malformed input.

Reviewed-by: Rich Salz <rsalz@openssl.org>

2 files changed, 41 insertions, 29 deletions

diff --git a/crypto/asn1/asn1_err.c b/crypto/asn1/asn1_err.c
index 0d1cf0cf57..73dd53f9db 100644
--- a/crypto/asn1/asn1_err.c
+++ b/crypto/asn1/asn1_err.c
@@ -103,7 +103,7 @@ static ERR_STRING_DATA ASN1_str_functs[] = {
     {ERR_FUNC(ASN1_F_ASN1_INTEGER_TO_BN), "ASN1_INTEGER_to_BN"},
     {ERR_FUNC(ASN1_F_ASN1_ITEM_D2I_FP), "ASN1_item_d2i_fp"},
     {ERR_FUNC(ASN1_F_ASN1_ITEM_DUP), "ASN1_item_dup"},
-    {ERR_FUNC(ASN1_F_ASN1_ITEM_EX_D2I), "ASN1_ITEM_EX_D2I"},
+    {ERR_FUNC(ASN1_F_ASN1_ITEM_EMBED_D2I), "asn1_item_embed_d2i"},
     {ERR_FUNC(ASN1_F_ASN1_ITEM_EMBED_NEW), "ASN1_ITEM_EMBED_NEW"},
     {ERR_FUNC(ASN1_F_ASN1_ITEM_I2D_BIO), "ASN1_item_i2d_bio"},
     {ERR_FUNC(ASN1_F_ASN1_ITEM_I2D_FP), "ASN1_item_i2d_fp"},
diff --git a/crypto/asn1/tasn_dec.c b/crypto/asn1/tasn_dec.c
index 939ee205be..94445bdc49 100644
--- a/crypto/asn1/tasn_dec.c
+++ b/crypto/asn1/tasn_dec.c
@@ -66,6 +66,10 @@
 #include <openssl/err.h>
 #include "asn1_locl.h"
 
+static int asn1_item_embed_d2i(ASN1_VALUE **pval, const unsigned char **in,
+                               long len, const ASN1_ITEM *it,
+                               int tag, int aclass, char opt, ASN1_TLC *ctx);
+
 static int asn1_check_eoc(const unsigned char **in, long len);
 static int asn1_find_end(const unsigned char **in, long len, char inf);
 
@@ -151,14 +155,25 @@ ASN1_VALUE *ASN1_item_d2i(ASN1_VALUE **pval,
     return NULL;
 }
 
+int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
+                     const ASN1_ITEM *it,
+                     int tag, int aclass, char opt, ASN1_TLC *ctx)
+{
+    int rv;
+    rv = asn1_item_embed_d2i(pval, in, len, it, tag, aclass, opt, ctx);
+    if (rv <= 0)
+        ASN1_item_ex_free(pval, it);
+    return rv;
+}
+
 /*
  * Decode an item, taking care of IMPLICIT tagging, if any. If 'opt' set and
  * tag mismatch return -1 to handle OPTIONAL
  */
 
-int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
-                     const ASN1_ITEM *it,
-                     int tag, int aclass, char opt, ASN1_TLC *ctx)
+static int asn1_item_embed_d2i(ASN1_VALUE **pval, const unsigned char **in,
+                               long len, const ASN1_ITEM *it,
+                               int tag, int aclass, char opt, ASN1_TLC *ctx)
 {
     const ASN1_TEMPLATE *tt, *errtt = NULL;
     const ASN1_EXTERN_FUNCS *ef;
@@ -189,7 +204,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
              * template in the template itself.
              */
             if ((tag != -1) || opt) {
-                ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
+                ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I,
                         ASN1_R_ILLEGAL_OPTIONS_ON_ITEM_TEMPLATE);
                 goto err;
             }
@@ -205,7 +220,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
         ret = asn1_check_tlen(NULL, &otag, &oclass, NULL, NULL,
                               &p, len, -1, 0, 1, ctx);
         if (!ret) {
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
             goto err;
         }
 
@@ -214,7 +229,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
             /* If OPTIONAL, assume this is OK */
             if (opt)
                 return -1;
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_MSTRING_NOT_UNIVERSAL);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_MSTRING_NOT_UNIVERSAL);
             goto err;
         }
         /* Check tag matches bit map */
@@ -222,7 +237,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
             /* If OPTIONAL, assume this is OK */
             if (opt)
                 return -1;
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_MSTRING_WRONG_TAG);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_MSTRING_WRONG_TAG);
             goto err;
         }
         return asn1_d2i_ex_primitive(pval, in, len, it, otag, 0, 0, ctx);
@@ -245,7 +260,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
                 asn1_set_choice_selector(pval, -1, it);
             }
         } else if (!ASN1_item_ex_new(pval, it)) {
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
             goto err;
         }
         /* CHOICE type, try each possibility in turn */
@@ -264,7 +279,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
                 break;
             /* Otherwise must be an ASN1 parsing error */
             errtt = tt;
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
             goto err;
         }
 
@@ -276,7 +291,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
                 ASN1_item_ex_free(pval, it);
                 return -1;
             }
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_NO_MATCHING_CHOICE_TYPE);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_NO_MATCHING_CHOICE_TYPE);
             goto err;
         }
 
@@ -300,7 +315,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
         ret = asn1_check_tlen(&len, NULL, NULL, &seq_eoc, &cst,
                               &p, len, tag, aclass, opt, ctx);
         if (!ret) {
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
             goto err;
         } else if (ret == -1)
             return -1;
@@ -312,12 +327,12 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
         else
             seq_nolen = seq_eoc;
         if (!cst) {
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_SEQUENCE_NOT_CONSTRUCTED);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_SEQUENCE_NOT_CONSTRUCTED);
             goto err;
         }
 
         if (!*pval && !ASN1_item_ex_new(pval, it)) {
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
             goto err;
         }
 
@@ -349,7 +364,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
             q = p;
             if (asn1_check_eoc(&p, len)) {
                 if (!seq_eoc) {
-                    ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_UNEXPECTED_EOC);
+                    ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_UNEXPECTED_EOC);
                     goto err;
                 }
                 len -= p - q;
@@ -388,12 +403,12 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
 
         /* Check for EOC if expecting one */
         if (seq_eoc && !asn1_check_eoc(&p, len)) {
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_MISSING_EOC);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_MISSING_EOC);
             goto err;
         }
         /* Check all data read */
         if (!seq_nolen && len) {
-            ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_SEQUENCE_LENGTH_MISMATCH);
+            ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_SEQUENCE_LENGTH_MISMATCH);
             goto err;
         }
 
@@ -413,7 +428,7 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
                 asn1_template_free(pseqval, seqtt);
             } else {
                 errtt = seqtt;
-                ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_FIELD_MISSING);
+                ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_FIELD_MISSING);
                 goto err;
             }
         }
@@ -429,9 +444,8 @@ int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
         return 0;
     }
  auxerr:
-    ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_AUX_ERROR);
+    ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_AUX_ERROR);
  err:
-    ASN1_item_ex_free(pval, it);
     if (errtt)
         ERR_add_error_data(4, "Field=", errtt->field_name,
                            ", Type=", it->sname);
@@ -513,7 +527,6 @@ static int asn1_template_ex_d2i(ASN1_VALUE **val,
     return 1;
 
  err:
-    asn1_template_free(val, tt);
     return 0;
 }
 
@@ -601,8 +614,8 @@ static int asn1_template_noexp_d2i(ASN1_VALUE **val,
                 break;
             }
             skfield = NULL;
-            if (!ASN1_item_ex_d2i(&skfield, &p, len,
-                                  ASN1_ITEM_ptr(tt->item), -1, 0, 0, ctx)) {
+            if (!asn1_item_embed_d2i(&skfield, &p, len,
+                                     ASN1_ITEM_ptr(tt->item), -1, 0, 0, ctx)) {
                 ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
                         ERR_R_NESTED_ASN1_ERROR);
                 goto err;
@@ -619,9 +632,9 @@ static int asn1_template_noexp_d2i(ASN1_VALUE **val,
         }
     } else if (flags & ASN1_TFLG_IMPTAG) {
         /* IMPLICIT tagging */
-        ret = ASN1_item_ex_d2i(val, &p, len,
-                               ASN1_ITEM_ptr(tt->item), tt->tag, aclass, opt,
-                               ctx);
+        ret = asn1_item_embed_d2i(val, &p, len,
+                                  ASN1_ITEM_ptr(tt->item), tt->tag, aclass, opt,
+                                  ctx);
         if (!ret) {
             ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ERR_R_NESTED_ASN1_ERROR);
             goto err;
@@ -629,8 +642,8 @@ static int asn1_template_noexp_d2i(ASN1_VALUE **val,
             return -1;
     } else {
         /* Nothing special */
-        ret = ASN1_item_ex_d2i(val, &p, len, ASN1_ITEM_ptr(tt->item),
-                               -1, 0, opt, ctx);
+        ret = asn1_item_embed_d2i(val, &p, len, ASN1_ITEM_ptr(tt->item),
+                                  -1, 0, opt, ctx);
         if (!ret) {
             ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ERR_R_NESTED_ASN1_ERROR);
             goto err;
@@ -642,7 +655,6 @@ static int asn1_template_noexp_d2i(ASN1_VALUE **val,
     return 1;
 
  err:
-    asn1_template_free(val, tt);
     return 0;
 }