From: Antoine_Beaupre <anarcat@orangeseeds.org>
Acked-by: Jiri Bohac <jbohac@suse.cz>
Subject: PR/51682: Avoid DoS with fragment out of order insertion; keep fragments sorted in the list.
References: bsc#1047443, CVE-2016-10396
Index: a/src/racoon/handler.h
===================================================================
--- a/src/racoon/handler.h.orig 2018-01-26 18:05:21.114764376 +0100
+++ a/src/racoon/handler.h 2018-01-26 18:05:33.986741103 +0100
@@ -141,6 +141,7 @@ struct ph1handle {
#endif
#ifdef ENABLE_FRAG
int frag; /* IKE phase 1 fragmentation */
+ int frag_last_index;
struct isakmp_frag_item *frag_chain; /* Received fragments */
#endif
Index: a/src/racoon/isakmp.c
===================================================================
--- a/src/racoon/isakmp.c.orig 2018-01-26 18:05:21.118764369 +0100
+++ a/src/racoon/isakmp.c 2018-01-26 18:05:33.986741103 +0100
@@ -1069,6 +1069,7 @@ isakmp_ph1begin_i(rmconf, remote, local)
iph1->frag = 1;
else
iph1->frag = 0;
+ iph1->frag_last_index = 0;
iph1->frag_chain = NULL;
#endif
iph1->approval = NULL;
@@ -1173,6 +1174,7 @@ isakmp_ph1begin_r(msg, remote, local, et
#endif
#ifdef ENABLE_FRAG
iph1->frag = 0;
+ iph1->frag_last_index = 0;
iph1->frag_chain = NULL;
#endif
iph1->approval = NULL;
Index: a/src/racoon/isakmp_frag.c
===================================================================
--- a/src/racoon/isakmp_frag.c.orig 2018-01-26 18:05:21.118764369 +0100
+++ a/src/racoon/isakmp_frag.c 2018-01-26 18:05:33.986741103 +0100
@@ -173,6 +173,43 @@ vendorid_frag_cap(gen)
return ntohl(hp[MD5_DIGEST_LENGTH / sizeof(*hp)]);
}
+static int
+isakmp_frag_insert(struct ph1handle *iph1, struct isakmp_frag_item *item)
+{
+ struct isakmp_frag_item *pitem = NULL;
+ struct isakmp_frag_item *citem = iph1->frag_chain;
+
+ /* no frag yet, just insert at beginning of list */
+ if (iph1->frag_chain == NULL) {
+ iph1->frag_chain = item;
+ return 0;
+ }
+
+ do {
+ /* duplicate fragment number, abort (CVE-2016-10396) */
+ if (citem->frag_num == item->frag_num)
+ return -1;
+
+ /* need to insert before current item */
+ if (citem->frag_num > item->frag_num) {
+ if (pitem != NULL)
+ pitem->frag_next = item;
+ else
+ /* insert at the beginning of the list */
+ iph1->frag_chain = item;
+ item->frag_next = citem;
+ return 0;
+ }
+
+ pitem = citem;
+ citem = citem->frag_next;
+ } while (citem != NULL);
+
+ /* we reached the end of the list, insert */
+ pitem->frag_next = item;
+ return 0;
+}
+
int
isakmp_frag_extract(iph1, msg)
struct ph1handle *iph1;
@@ -224,39 +261,43 @@ isakmp_frag_extract(iph1, msg)
item->frag_next = NULL;
item->frag_packet = buf;
- /* Look for the last frag while inserting the new item in the chain */
- if (item->frag_last)
- last_frag = item->frag_num;
+ /* Check for the last frag before inserting the new item in the chain */
+ if (item->frag_last) {
+ /* if we have the last fragment, indices must match */
+ if (iph1->frag_last_index != 0 &&
+ item->frag_last != iph1->frag_last_index) {
+ plog(LLV_ERROR, LOCATION, NULL,
+ "Repeated last fragment index mismatch\n");
+ racoon_free(item);
+ vfree(buf);
+ return -1;
+ }
- if (iph1->frag_chain == NULL) {
- iph1->frag_chain = item;
- } else {
- struct isakmp_frag_item *current;
+ last_frag = iph1->frag_last_index = item->frag_num;
+ }
- current = iph1->frag_chain;
- while (current->frag_next) {
- if (current->frag_last)
- last_frag = item->frag_num;
- current = current->frag_next;
- }
- current->frag_next = item;
+ /* insert fragment into chain */
+ if (isakmp_frag_insert(iph1, item) == -1) {
+ plog(LLV_ERROR, LOCATION, NULL,
+ "Repeated fragment index mismatch\n");
+ racoon_free(item);
+ vfree(buf);
+ return -1;
}
- /* If we saw the last frag, check if the chain is complete */
+ /* If we saw the last frag, check if the chain is complete
+ * we have a sorted list now, so just walk through */
if (last_frag != 0) {
+ item = iph1->frag_chain;
for (i = 1; i <= last_frag; i++) {
- item = iph1->frag_chain;
- do {
- if (item->frag_num == i)
- break;
- item = item->frag_next;
- } while (item != NULL);
-
+ if (item->frag_num != i)
+ break;
+ item = item->frag_next;
if (item == NULL) /* Not found */
break;
}
- if (item != NULL) /* It is complete */
+ if (i > last_frag) /* It is complete */
return 1;
}
@@ -291,15 +332,9 @@ isakmp_frag_reassembly(iph1)
}
data = buf->v;
+ item = iph1->frag_chain;
for (i = 1; i <= frag_count; i++) {
- item = iph1->frag_chain;
- do {
- if (item->frag_num == i)
- break;
- item = item->frag_next;
- } while (item != NULL);
-
- if (item == NULL) {
+ if (item->frag_num != i) {
plog(LLV_ERROR, LOCATION, NULL,
"Missing fragment #%d\n", i);
vfree(buf);
@@ -308,6 +343,7 @@ isakmp_frag_reassembly(iph1)
}
memcpy(data, item->frag_packet->v, item->frag_packet->l);
data += item->frag_packet->l;
+ item = item->frag_next;
}
out:
diff -u -p -r1.50 -r1.51
--- a/src/racoon/isakmp_inf.c 2013/04/12 09:53:10 1.50
+++ a/src/racoon/isakmp_inf.c 2017/01/24 19:23:56 1.51
@@ -720,6 +720,7 @@ isakmp_info_send_nx(isakmp, remote, loca
#endif
#ifdef ENABLE_FRAG
iph1->frag = 0;
+ iph1->frag_last_index = 0;
iph1->frag_chain = NULL;
#endif