Ethereal-dev: [Ethereal-dev] Bug in asn2eth - not properly handling .FN_BODY with "%s" in it?

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From: Guy Harris <gharris@xxxxxxxxx>
Date: Mon, 17 Oct 2005 16:43:47 -0700
sahlberg@xxxxxxxxxxxx wrote:

User: sahlberg
Date: 2005/10/15 05:46 PM

Log:
 remove some strcpy() calls

Directory: /trunk/asn1/acse/
  Changes    Path          Action
  +1 -1      acse.cnf      Modified


That change replaced

	strcpy(object_identifier_id, oid);

with

	g_snprintf(object_identifier_id, MAX_OID_STR_LEN, "%s", oid);

inside the #.FN_BODY EXTERNAL/indirect-reference section.

Unfortunately, it appears that asn2eth turned that into
g_snprintf(object_identifier_id, MAX_OID_STR_LEN, "{'DEFAULT_BODY': ' offset = dissect_ber_integer(implicit_tag, pinfo, tree, tvb, offset, hf_index,\n NULL);\n', 'VAL_PTR': 'NULL', 'TREE': 'tree', 'FN_VARIANT': '', 'HF_INDEX': 'hf_index', 'PINFO': 'pinfo', 'CREATED_ITEM_PTR': 'NULL', 'OFFSET': 'offset', 'TNAME': 'T_indirect_reference', 'ER': 'ber', 'IMPLICIT_TAG': 'implicit_tag', 'TVB': 'tvb'}", oid);
which presumably isn't what's intended, and which generates warnings from the compiler. 

The "eth_type_fn_body" method does

    if pars:
      out = out % pars
which means that if out contains any "%" characters, they'll be treated as introducing a printf-like format sequence, and substitution will be done.
Does this mean that it's unsafe to use any printf-like procedure calls inside #.FN_BODY sections? If so, that should either be documented (complete with a workaround!), or fixed.