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You can't return from inside a TRY/CATCH/ENDTRY block (see 

epan/exceptions.h; it crashes).

Try BER first, including both the test dissection and the check of the
results.  If that fails due to an exception being thrown, or due to the
results not indicating that it's a BER-encoded T.125 packet, try PER, so
that if the BER dissection doesn't work we don't just give up.

Get rid of some _U_s attached to parameters that are, in fact, used.

svn path=/trunk/; revision=46066
This commit is contained in:
Guy Harris 2012-11-18 01:39:32 +00:00
parent de2aa05555
commit e5c2f19eab
2 changed files with 66 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
asn1/t125/packet-t125-template.c
View File

@ -58,7 +58,7 @@ static heur_dissector_list_t t125_heur_subdissector_list;
#include "packet-t125-fn.c"
static int
dissect_t125(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *parent_tree, void *data _U_)
dissect_t125(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
{
proto_item *item = NULL;
proto_tree *tree = NULL;
@ -87,31 +87,51 @@ dissect_t125(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *parent_tree, voi
}
static gboolean
dissect_t125_heur(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *parent_tree, void *data _U_)
dissect_t125_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
{
gint8 ber_class;
gboolean pc;
gint32 tag;
guint32 choice_index = 100;
asn1_ctx_t asn1_ctx;
gboolean failed;
asn1_ctx_init(&asn1_ctx, ASN1_ENC_PER, TRUE, pinfo);
/*
* We must catch all the "ran past the end of the packet" exceptions
* here and, if we catch one, just return FALSE. It's too painful
* to have a version of dissect_per_sequence() that checks all
* references to the tvbuff before making them and returning "no"
* if they would fail.
*/
failed = FALSE;
TRY {
asn1_ctx_init(&asn1_ctx, ASN1_ENC_PER, TRUE, pinfo);
/* could be BER */
get_ber_identifier(tvb, 0, &ber_class, &pc, &tag);
/* or PER */
dissect_per_constrained_integer(tvb, 0, &asn1_ctx,
NULL, hf_t125_heur, 0, 42,
&choice_index, FALSE);
} CATCH_ALL {
return FALSE;
} CATCH2(BoundsError, ReportedBoundsError) {
failed = TRUE;
} ENDTRY;
/* is this strong enough ? */
if ( ((ber_class==BER_CLASS_APP) && ((tag>=101) && (tag<=104))) ||
(choice_index <=42)) {
if (!failed && ((ber_class==BER_CLASS_APP) && ((tag>=101) && (tag<=104)))) {
dissect_t125(tvb, pinfo, parent_tree, NULL);
return TRUE;
}
failed = FALSE;
TRY {
/* or PER */
dissect_per_constrained_integer(tvb, 0, &asn1_ctx,
NULL, hf_t125_heur, 0, 42,
&choice_index, FALSE);
} CATCH2(BoundsError, ReportedBoundsError) {
failed = TRUE;
} ENDTRY;
/* is this strong enough ? */
if (!failed && (choice_index <=42)) {
dissect_t125(tvb, pinfo, parent_tree, NULL);
return TRUE;

48
epan/dissectors/packet-t125.c
View File

@ -386,7 +386,7 @@ static int dissect_ConnectMCSPDU_PDU(tvbuff_t *tvb _U_, packet_info *pinfo _U_,
#line 59 "../../asn1/t125/packet-t125-template.c"
static int
dissect_t125(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *parent_tree, void *data _U_)
dissect_t125(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
{
proto_item *item = NULL;
proto_tree *tree = NULL;
@ -415,31 +415,51 @@ dissect_t125(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *parent_tree, voi
}
static gboolean
dissect_t125_heur(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *parent_tree, void *data _U_)
dissect_t125_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
{
gint8 ber_class;
gboolean pc;
gint32 tag;
guint32 choice_index = 100;
asn1_ctx_t asn1_ctx;
gboolean failed;
asn1_ctx_init(&asn1_ctx, ASN1_ENC_PER, TRUE, pinfo);
/*
* We must catch all the "ran past the end of the packet" exceptions
* here and, if we catch one, just return FALSE. It's too painful
* to have a version of dissect_per_sequence() that checks all
* references to the tvbuff before making them and returning "no"
* if they would fail.
*/
failed = FALSE;
TRY {
asn1_ctx_init(&asn1_ctx, ASN1_ENC_PER, TRUE, pinfo);
/* could be BER */
get_ber_identifier(tvb, 0, &ber_class, &pc, &tag);
/* or PER */
dissect_per_constrained_integer(tvb, 0, &asn1_ctx,
NULL, hf_t125_heur, 0, 42,
&choice_index, FALSE);
} CATCH_ALL {
return FALSE;
} CATCH2(BoundsError, ReportedBoundsError) {
failed = TRUE;
} ENDTRY;
/* is this strong enough ? */
if ( ((ber_class==BER_CLASS_APP) && ((tag>=101) && (tag<=104))) ||
(choice_index <=42)) {
if (!failed && ((ber_class==BER_CLASS_APP) && ((tag>=101) && (tag<=104)))) {
dissect_t125(tvb, pinfo, parent_tree, NULL);
return TRUE;
}
failed = FALSE;
TRY {
/* or PER */
dissect_per_constrained_integer(tvb, 0, &asn1_ctx,
NULL, hf_t125_heur, 0, 42,
&choice_index, FALSE);
} CATCH2(BoundsError, ReportedBoundsError) {
failed = TRUE;
} ENDTRY;
/* is this strong enough ? */
if (!failed && (choice_index <=42)) {
dissect_t125(tvb, pinfo, parent_tree, NULL);
return TRUE;
@ -567,7 +587,7 @@ void proto_register_t125(void) {
NULL, HFILL }},
/*--- End of included file: packet-t125-hfarr.c ---*/
#line 138 "../../asn1/t125/packet-t125-template.c"
#line 158 "../../asn1/t125/packet-t125-template.c"
};
/* List of subtrees */
@ -584,7 +604,7 @@ void proto_register_t125(void) {
&ett_t125_ConnectMCSPDU,
/*--- End of included file: packet-t125-ettarr.c ---*/
#line 144 "../../asn1/t125/packet-t125-template.c"
#line 164 "../../asn1/t125/packet-t125-template.c"
};
/* Register protocol */