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Updated get_ber_length to handle multiple nested indefinite length encodings. 

svn path=/trunk/; revision=33046
This commit is contained in:
Graeme Lunt 2010-06-02 13:33:37 +00:00
parent 970dbcb464
commit 3644d0faa7
1 changed files with 20 additions and 38 deletions
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58
epan/dissectors/packet-ber.c
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@ -831,10 +831,13 @@ static gboolean
try_get_ber_length(tvbuff_t *tvb, int *bl_offset, guint32 *length, gboolean *ind) {
int offset = *bl_offset;
guint8 oct, len;
/* guint32 tmp_len; */
guint32 tmp_len;
guint32 tmp_length;
gboolean tmp_ind;
int tmp_offset;
gint8 tclass;
gint32 ttag;
tmp_length = 0;
tmp_ind = FALSE;
@ -856,20 +859,21 @@ try_get_ber_length(tvbuff_t *tvb, int *bl_offset, guint32 *length, gboolean *ind
} else {
/* 8.1.3.6 */
/* indefinite length encoded - must be constructed */
tmp_offset = offset;
/* check for EOC */
if (tvb_get_guint8(tvb, offset) || tvb_get_guint8(tvb, offset+1)) {
if (length)
*length = 0;
if (ind)
*ind = tmp_ind;
do {
tmp_offset = get_ber_identifier(tvb, tmp_offset, &tclass, NULL, &ttag);
try_get_ber_length(tvb, &tmp_offset, &tmp_len, &tmp_ind);
*bl_offset = offset;
return FALSE;
}
tmp_length += 2;
tmp_offset += tmp_len;
} while (!((tclass == BER_CLASS_UNI) && (ttag == 0) && (tmp_len == 0)));
tmp_length = tmp_offset - offset;
tmp_ind = TRUE;
offset = tmp_offset;
}
}
@ -887,37 +891,15 @@ printf("get BER length %d, offset %d (remaining %d)\n", tmp_length, offset, tvb_
}
int
get_ber_length(tvbuff_t *tvb, int offset, guint32 *length, gboolean *ind) {
get_ber_length(tvbuff_t *tvb, int offset, guint32 *length, gboolean *ind)
{
int bl_offset = offset;
int s_offset;
guint32 bl_length;
guint32 tot_length = 0;
gint8 tclass;
gboolean tpc;
gint32 ttag;
while (1) {
/* Traverse the BER to find the length. This will fix most indefinite length issues. */
/* Assumption here is that indefinite length is always used on constructed types*/
s_offset = bl_offset;
if (try_get_ber_length(tvb, &bl_offset, &bl_length, ind)) {
/* No more lengths to fetch. */
tot_length += bl_length;
break;
}
/* We're in the middle of an indefinite length. */
bl_offset = get_ber_identifier(tvb, bl_offset, &tclass, &tpc, &ttag);
/* Make sure we've moved forward in the packet */
if (bl_offset <= s_offset)
THROW(ReportedBoundsError);
tot_length += (bl_offset - s_offset); /* length + tag and length */
}
try_get_ber_length(tvb, &bl_offset, &bl_length, ind);
if (length)
*length = tot_length;
*length = bl_length;
return bl_offset;
}