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Revert the optimization in r52578. As Jakub predicted, it caused at least one 

infinite loop to pop up. We're just going to have to eat the performance hit.
(https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=9282)

svn path=/trunk/; revision=52660
This commit is contained in:
Evan Huus 2013-10-17 12:24:25 +00:00
parent 744f47107e
commit cbe8af0a8b
3 changed files with 44 additions and 26 deletions
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52
epan/proto.c
View File

@ -1750,6 +1750,45 @@ ptvcursor_add(ptvcursor_t *ptvc, int hfindex, gint length,
offset, length, encoding);
}
/*
* Validates that field length bytes are available starting from
* start (pos/neg). Throws an exception if they aren't.
*/
static void
test_length(header_field_info *hfinfo, proto_tree *tree, tvbuff_t *tvb,
gint start, gint length, const guint encoding)
{
gint size = length;
if (!tvb)
return;
if (hfinfo->type == FT_UINT_BYTES || hfinfo->type == FT_UINT_STRING) {
guint32 n;
n = get_uint_value(tree, tvb, start, length, encoding);
if (n > size + n) {
/* If n > size + n then we have an integer overflow, so
* set size to -1, which will force the
* tvb_ensure_bytes_exist call below to throw a
* ReportedBoundsError
*/
size = -1;
}
else {
size += n;
}
} else if (hfinfo->type == FT_STRINGZ) {
/* If we're fetching until the end of the TVB, only validate
* that the offset is within range.
*/
if (length == -1)
size = 0;
}
tvb_ensure_bytes_exist(tvb, start, size);
}
/* Add an item to a proto_tree, using the text label registered to that item;
the item is extracted from the tvbuff handed to it. */
proto_item *
@ -1761,13 +1800,11 @@ proto_tree_add_item_new(proto_tree *tree, header_field_info *hfinfo, tvbuff_t *t
DISSECTOR_ASSERT_HINT(hfinfo != NULL, "Not passed hfi!");
if (tvb) {
tvb_ensure_offset_exists(tvb, start);
}
get_hfi_length(hfinfo, tvb, start, &length, &item_length);
test_length(hfinfo, tree, tvb, start, item_length, encoding);
TRY_TO_FAKE_THIS_ITEM(tree, hfinfo->id, hfinfo);
get_hfi_length(hfinfo, tvb, start, &length, &item_length);
new_fi = new_field_info(tree, hfinfo, tvb, start, item_length);
if (new_fi == NULL)
@ -6959,15 +6996,14 @@ proto_tree_add_bits_item(proto_tree *tree, const int hfindex, tvbuff_t *tvb,
const guint encoding)
{
header_field_info *hfinfo;
gint octet_length;
gint octet_offset;
PROTO_REGISTRAR_GET_NTH(hfindex, hfinfo);
octet_length = (no_of_bits + 7) >> 3;
octet_offset = bit_offset >> 3;
if (tvb) {
tvb_ensure_offset_exists(tvb, octet_offset);
}
test_length(hfinfo, tree, tvb, octet_offset, octet_length, encoding);
/* Yes, we try to fake this item again in proto_tree_add_bits_ret_val()
* but only after doing a bunch more work (which we can, in the common

15
epan/tvbuff.c
View File

@ -510,21 +510,6 @@ tvb_offset_exists(const tvbuff_t *tvb, const gint offset)
}
}
/* Like tvb_offset_exists except it throws an exception instead of returning
* FALSE */
void
tvb_ensure_offset_exists(const tvbuff_t *tvb, const gint offset)
{
guint abs_offset;
int exception;
DISSECTOR_ASSERT(tvb && tvb->initialized);
exception = compute_offset(tvb, offset, &abs_offset);
if (exception)
THROW(exception);
}
guint
tvb_reported_length(const tvbuff_t *tvb)
{

3
epan/tvbuff.h
View File

@ -239,9 +239,6 @@ WS_DLL_PUBLIC void tvb_ensure_bytes_exist(const tvbuff_t *tvb, const gint offset
/* Checks (w/o throwing exception) that offset exists in buffer */
WS_DLL_PUBLIC gboolean tvb_offset_exists(const tvbuff_t*, const gint offset);
/* Checks that offset exists in buffer and throws an exception if it doesn't */
WS_DLL_PUBLIC void tvb_ensure_offset_exists(const tvbuff_t*, const gint offset);
/* Get reported length of buffer */
WS_DLL_PUBLIC guint tvb_reported_length(const tvbuff_t*);