sm: More improvements for PKCS#12 parsing for latest IVBB changes.

* common/tlv.h (TLV_PARSER_FLAG_T5793): New.
(tlv_parser_new): New macro.  Rename function with an underscore.
(tlv_next_with_flag): New.
* common/tlv-parser.c (struct tlv_parser_s): Remove const from buffer.
Add fields crammed, lasttlv, and origoff.  Remove bufferlist ands ist
definition.
(dump_to_file): New but disabled debug helper.
(parse_tag): Print more info on error.
(_tlv_parser_new): Add args lasttlv and LNO.  Take a copy of the data.
(_tlv_parser_release): Free the copy of the buffer and return the
recorded TLV object from tlv_parser_new.
(_tlv_peek, tlv_parser_peek, _tlv_parser_peek_null): Remove.
(_tlv_push): Record crammed length.
(_tlv_pop): Restore crammed length.
(_tlv_parser_next): Add arg flags.  More debug output.  Handle cramming
here.  Take care of cramming here.
(tlv_expect_object): Simplify to adjust for changes in _tlv_parser_next.
(tlv_expect_octet_string): Remove arg encapsulates.  Adjust for
changes in _tlv_parser_next.  Change all allers.
(tlv_expect_null): New.
(cram_octet_string): Rewrite.
(need_octet_string_cramming): Remove.

* sm/minip12.c (dump_to_file): New.  Enable in debug mode and if an
envvar ist set.  Replace all explict but disabled dumping to call this
function.
(parse_bag_encrypted_data): Replace tlv_peek_null and a peeking for an
optional SET by non-peeking code.
(parse_cert_bag): Ditto.
(parse_shrouded_key_bag): Replace tlv_peek_null by non-peeking code.
(parse_bag_encrypted_data): Use the new TLV_PARSER_FLAG_T5793 to
enable the Mozilla workaround.
(parse_bag_encrypted_data): Replace the 'renewed_tlv' code by the new
tlv_parser_release semantics.
(parse_shrouded_key_bag): Ditto.
(parse_shrouded_key_bag): Create a new context instead of using the
former encapsulated mechanism for tlv_expect_octet_string.
(parse_bag_data): Ditto.
(p12_parse): Ditto.

* common/tlv-parser.c: New
* common/Makefile.am: Add new file.
--

GnuPG-bug-id: 7213
Backported-from-master: 690fd61a0c

This backport required to introduce the new tlv-parser.c file and
remove most source copied stuff from minip12.c.  Thus the above
ChangeList is not fully correct.

common/Makefile.am

@@ -61,7 +61,7 @@ common_sources = \
 	openpgpdefs.h \
 	gc-opt-flags.h \
 	sexp-parse.h \
-	tlv.c tlv.h tlv-builder.c \
+	tlv.c tlv.h tlv-builder.c tlv-parser.c \
 	init.c init.h \
 	sexputil.c \
 	sysutils.c sysutils.h \

common/tlv.h

@@ -72,10 +72,22 @@ enum tlv_tag_type {
   TAG_BMP_STRING = 30
 };
 
+struct tag_info
+{
+  int class;
+  int is_constructed;
+  unsigned long tag;
+  size_t length;         /* length part of the TLV */
+  size_t nhdr;
+  int ndef;              /* It is an indefinite length */
+};
 
 struct tlv_builder_s;
 typedef struct tlv_builder_s *tlv_builder_t;
 
+struct tlv_parser_s;
+typedef struct tlv_parser_s *tlv_parser_t;
+
 /*-- tlv.c --*/
 
 /* Locate a TLV encoded data object in BUFFER of LENGTH and return a
@@ -138,6 +150,59 @@ void put_tlv_to_membuf (membuf_t *membuf, int class, int tag,
 size_t get_tlv_length (int class, int tag, int constructed, size_t length);
 
 
+/*-- tlv-parser.c --*/
+#define TLV_PARSER_FLAG_T5793 1  /* Enable workaround for Mozilla bug. */
+
+tlv_parser_t _tlv_parser_new (const unsigned char *buffer, size_t bufsize,
+                              int verbosity, tlv_parser_t lasttlv, int lno);
+tlv_parser_t _tlv_parser_release (tlv_parser_t tlv, int lno);
+
+void _tlv_parser_dump_tag (const char *text, int lno, tlv_parser_t tlv);
+void _tlv_parser_dump_state (const char *text, const char *text2,
+                             int lno, tlv_parser_t tlv);
+
+gpg_error_t _tlv_parser_next (tlv_parser_t tlv, unsigned int flags, int lno);
+
+unsigned int tlv_parser_level (tlv_parser_t tlv);
+size_t tlv_parser_offset (tlv_parser_t tlv);
+const char *tlv_parser_lastfunc (tlv_parser_t tlv);
+const char *tlv_parser_lasterrstr (tlv_parser_t tlv);
+void tlv_parser_set_pending (tlv_parser_t tlv);
+size_t tlv_parser_tag_length (tlv_parser_t tlv, int with_header);
+
+void tlv_parser_skip (tlv_parser_t tlv);
+
+gpg_error_t tlv_expect_sequence (tlv_parser_t tlv);
+gpg_error_t tlv_expect_context_tag (tlv_parser_t tlv, int *r_tag);
+gpg_error_t tlv_expect_set (tlv_parser_t tlv);
+gpg_error_t tlv_expect_object (tlv_parser_t tlv, int class, int tag,
+                               unsigned char const **r_data,
+                               size_t *r_datalen);
+gpg_error_t tlv_expect_octet_string (tlv_parser_t tlv,
+                                     unsigned char const **r_data,
+                                     size_t *r_datalen);
+gpg_error_t tlv_expect_integer (tlv_parser_t tlv, int *r_value);
+#ifdef GCRYPT_VERSION
+gpg_error_t tlv_expect_mpinteger (tlv_parser_t tlv, int ignore_zero,
+                                  gcry_mpi_t *r_value);
+#endif
+gpg_error_t tlv_expect_object_id (tlv_parser_t tlv,
+                                  unsigned char const **r_oid,
+                                  size_t *r_oidlen);
+gpg_error_t tlv_expect_null (tlv_parser_t tlv);
+
+/* Easier to use wrapper around parse_ber_header.  */
+gpg_error_t tlv_parse_tag (unsigned char const **buffer,
+                           size_t *size, struct tag_info *ti);
+
+/* Convenience macro and macros to include the line number.  */
+#define tlv_parser_new(a,b,c,d) _tlv_parser_new ((a),(b),(c),(d), __LINE__)
+#define tlv_parser_release(a) _tlv_parser_release ((a), __LINE__)
+#define tlv_parser_dump_tag(a,b) _tlv_parser_dump_tag ((a),__LINE__,(b))
+#define tlv_parser_dump_state(a,b,c) \
+                            _tlv_parser_dump_state ((a),(b),__LINE__,(c))
+#define tlv_next(a) _tlv_parser_next ((a),0, __LINE__)
+#define tlv_next_with_flag(a,b) _tlv_parser_next ((a),(b), __LINE__)
 
 
 #endif /* SCD_TLV_H */