[libpri-commits] rmudgett: branch 1.4 r1674 - /branches/1.4/q931.c
SVN commits to the libpri project
libpri-commits at lists.digium.com
Mon Apr 26 14:39:33 CDT 2010
Author: rmudgett
Date: Mon Apr 26 14:39:28 2010
New Revision: 1674
URL: http://svnview.digium.com/svn/libpri?view=rev&rev=1674
Log:
Garbage on the end of Q.931 messages causing calls to fail to connect.
The DAHDI driver had a bug where an extra byte appeared on the end of
Q.931 messages. This garbage byte caused the message to be discarded with
the diagnostic "XXX Message longer than it should be?? XXX". The Q.931
message will no longer be discarded if there were earlier ie's in the
message.
This patch also addresses the potential problem of reading beyond the
buffer when trying to parse the garbage data.
Thanks to roeften for the base patch.
(closes issue #14378)
Reported by: timking
Modified:
branches/1.4/q931.c
Modified: branches/1.4/q931.c
URL: http://svnview.digium.com/svn/libpri/branches/1.4/q931.c?view=diff&rev=1674&r1=1673&r2=1674
==============================================================================
--- branches/1.4/q931.c (original)
+++ branches/1.4/q931.c Mon Apr 26 14:39:28 2010
@@ -3348,6 +3348,25 @@
return 2 + ie->len;
}
+static inline int ielen_checked(q931_ie *ie, int len_remaining)
+{
+ int len;
+
+ if (ie->ie & 0x80) {
+ len = 1;
+ } else if (len_remaining < 2) {
+ /* There is no length octet when there should be. */
+ len = -1;
+ } else {
+ len = 2 + ie->len;
+ if (len_remaining < len) {
+ /* There is not enough room left in the packet for this ie. */
+ len = -1;
+ }
+ }
+ return len;
+}
+
const char *msg2str(int msg)
{
unsigned int x;
@@ -3881,13 +3900,20 @@
{
q931_mh *mh;
char c;
- int x=0, r;
+ int x;
+ int r;
int cur_codeset;
int codeset;
int cref;
c = txrx ? '>' : '<';
pri_message(ctrl, "%c Protocol Discriminator: %s (%d) len=%d\n", c, disc2str(h->pd), h->pd, len);
+
+ if (len < 2 || len < 2 + h->crlen) {
+ pri_message(ctrl, "%c Message too short for call reference. len=%d\n",
+ c, len);
+ return;
+ }
cref = q931_cr(h);
pri_message(ctrl, "%c TEI=%d Call Ref: len=%2d (reference %d/0x%X) (%s)\n",
c, tei, h->crlen, cref & ~Q931_CALL_REFERENCE_FLAG,
@@ -3896,6 +3922,12 @@
: (cref & Q931_CALL_REFERENCE_FLAG)
? "Sent to originator" : "Sent from originator");
+ if (len < 3 + h->crlen) {
+ pri_message(ctrl, "%c Message too short for supported protocols. len=%d\n",
+ c, len);
+ return;
+ }
+
/* Message header begins at the end of the call reference number */
mh = (q931_mh *)(h->contents + h->crlen);
if ((h->pd == MAINTENANCE_PROTOCOL_DISCRIMINATOR_1) || (h->pd == MAINTENANCE_PROTOCOL_DISCRIMINATOR_2)) {
@@ -3906,8 +3938,14 @@
/* Drop length of header, including call reference */
len -= (h->crlen + 3);
codeset = cur_codeset = 0;
- while(x < len) {
- r = ielen((q931_ie *)(mh->data + x));
+ for (x = 0; x < len; x += r) {
+ r = ielen_checked((q931_ie *) (mh->data + x), len - x);
+ if (r < 0) {
+ /* We have garbage on the end of the packet. */
+ pri_message(ctrl, "Not enough room for codeset:%d ie:%d(%02x)\n", cur_codeset,
+ mh->data[x], mh->data[x]);
+ break;
+ }
q931_dumpie(ctrl, cur_codeset, (q931_ie *)(mh->data + x), c);
switch (mh->data[x] & 0xf8) {
case Q931_LOCKING_SHIFT:
@@ -3921,10 +3959,7 @@
/* Reset temporary codeset change */
cur_codeset = codeset;
}
- x += r;
- }
- if (x > len)
- pri_error(ctrl, "XXX Message longer than it should be?? XXX\n");
+ }
}
static int q931_handle_ie(int codeset, struct pri *ctrl, q931_call *c, int msg, q931_ie *ie)
@@ -5854,6 +5889,10 @@
#ifdef LIBPRI_COUNTERS
ctrl->q931_rxcount++;
#endif
+ if (len < 3 || len < 3 + h->crlen) {
+ /* Message too short for supported protocols. */
+ return -1;
+ }
mh = (q931_mh *)(h->contents + h->crlen);
if ((h->pd != ctrl->protodisc) && (h->pd != MAINTENANCE_PROTOCOL_DISCRIMINATOR_1) && (h->pd != MAINTENANCE_PROTOCOL_DISCRIMINATOR_2)) {
pri_error(ctrl, "Warning: unknown/inappropriate protocol discriminator received (%02x/%d)\n", h->pd, h->pd);
@@ -5912,20 +5951,24 @@
memcpy(mandies, msgs[x].mandies, sizeof(mandies));
}
}
- x = 0;
/* Do real IE processing */
len -= (h->crlen + 3);
codeset = cur_codeset = 0;
- while(len) {
+ for (x = 0; x < len; x += r) {
ie = (q931_ie *)(mh->data + x);
+ r = ielen_checked(ie, len - x);
+ if (r < 0) {
+ /* We have garbage on the end of the packet. */
+ pri_error(ctrl, "XXX Message longer than it should be?? XXX\n");
+ if (x) {
+ /* Allow the message anyway. We have already processed an ie. */
+ break;
+ }
+ return -1;
+ }
for (y=0;y<MAX_MAND_IES;y++) {
if (mandies[y] == Q931_FULL_IE(cur_codeset, ie->ie))
mandies[y] = 0;
- }
- r = ielen(ie);
- if (r > len) {
- pri_error(ctrl, "XXX Message longer than it should be?? XXX\n");
- return -1;
}
/* Special processing for codeset shifts */
switch (ie->ie & 0xf8) {
@@ -5976,8 +6019,6 @@
/* Reset current codeset */
cur_codeset = codeset;
}
- x += r;
- len -= r;
}
missingmand = 0;
for (x=0;x<MAX_MAND_IES;x++) {
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