mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-20 06:08:08 +00:00
dnsmasq: Backport DHCPv6 server fix (CVE-2022-0934)
This backports a commit from upstream dnsmasq to fix CVE-2022-0934.
CVE-2022-0934 description:
A single-byte, non-arbitrary write/use-after-free flaw was found in
dnsmasq. This flaw allows an attacker who sends a crafted packet
processed by dnsmasq, potentially causing a denial of service.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
(cherry picked from commit 002a99eccd)
This commit is contained in:
Hauke Mehrtens
parent
13bd217821
commit
77522d4eb7
@ -0,0 +1,179 @@
|
||||
From 03345ecefeb0d82e3c3a4c28f27c3554f0611b39 Mon Sep 17 00:00:00 2001
|
||||
From: Simon Kelley <simon@thekelleys.org.uk>
|
||||
Date: Thu, 31 Mar 2022 21:35:20 +0100
|
||||
Subject: Fix write-after-free error in DHCPv6 code. CVE-2022-0934 refers.
|
||||
|
||||
---
|
||||
CHANGELOG | 3 +++
|
||||
src/rfc3315.c | 48 +++++++++++++++++++++++++++---------------------
|
||||
2 files changed, 30 insertions(+), 21 deletions(-)
|
||||
|
||||
--- a/CHANGELOG
|
||||
+++ b/CHANGELOG
|
||||
@@ -92,6 +92,9 @@ version 2.86
|
||||
of filename). Thanks to Ed Wildgoose for the initial patch
|
||||
and motivation for this.
|
||||
|
||||
+ Fix write-after-free error in DHCPv6 server code.
|
||||
+ CVE-2022-0934 refers.
|
||||
+
|
||||
|
||||
version 2.85
|
||||
Fix problem with DNS retries in 2.83/2.84.
|
||||
--- a/src/rfc3315.c
|
||||
+++ b/src/rfc3315.c
|
||||
@@ -33,9 +33,9 @@ struct state {
|
||||
unsigned int mac_len, mac_type;
|
||||
};
|
||||
|
||||
-static int dhcp6_maybe_relay(struct state *state, void *inbuff, size_t sz,
|
||||
+static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t sz,
|
||||
struct in6_addr *client_addr, int is_unicast, time_t now);
|
||||
-static int dhcp6_no_relay(struct state *state, int msg_type, void *inbuff, size_t sz, int is_unicast, time_t now);
|
||||
+static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbuff, size_t sz, int is_unicast, time_t now);
|
||||
static void log6_opts(int nest, unsigned int xid, void *start_opts, void *end_opts);
|
||||
static void log6_packet(struct state *state, char *type, struct in6_addr *addr, char *string);
|
||||
static void log6_quiet(struct state *state, char *type, struct in6_addr *addr, char *string);
|
||||
@@ -104,12 +104,12 @@ unsigned short dhcp6_reply(struct dhcp_c
|
||||
}
|
||||
|
||||
/* This cost me blood to write, it will probably cost you blood to understand - srk. */
|
||||
-static int dhcp6_maybe_relay(struct state *state, void *inbuff, size_t sz,
|
||||
+static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t sz,
|
||||
struct in6_addr *client_addr, int is_unicast, time_t now)
|
||||
{
|
||||
void *end = inbuff + sz;
|
||||
void *opts = inbuff + 34;
|
||||
- int msg_type = *((unsigned char *)inbuff);
|
||||
+ int msg_type = *inbuff;
|
||||
unsigned char *outmsgtypep;
|
||||
void *opt;
|
||||
struct dhcp_vendor *vendor;
|
||||
@@ -259,15 +259,15 @@ static int dhcp6_maybe_relay(struct stat
|
||||
return 1;
|
||||
}
|
||||
|
||||
-static int dhcp6_no_relay(struct state *state, int msg_type, void *inbuff, size_t sz, int is_unicast, time_t now)
|
||||
+static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbuff, size_t sz, int is_unicast, time_t now)
|
||||
{
|
||||
void *opt;
|
||||
- int i, o, o1, start_opts;
|
||||
+ int i, o, o1, start_opts, start_msg;
|
||||
struct dhcp_opt *opt_cfg;
|
||||
struct dhcp_netid *tagif;
|
||||
struct dhcp_config *config = NULL;
|
||||
struct dhcp_netid known_id, iface_id, v6_id;
|
||||
- unsigned char *outmsgtypep;
|
||||
+ unsigned char outmsgtype;
|
||||
struct dhcp_vendor *vendor;
|
||||
struct dhcp_context *context_tmp;
|
||||
struct dhcp_mac *mac_opt;
|
||||
@@ -296,12 +296,13 @@ static int dhcp6_no_relay(struct state *
|
||||
v6_id.next = state->tags;
|
||||
state->tags = &v6_id;
|
||||
|
||||
- /* copy over transaction-id, and save pointer to message type */
|
||||
- if (!(outmsgtypep = put_opt6(inbuff, 4)))
|
||||
+ start_msg = save_counter(-1);
|
||||
+ /* copy over transaction-id */
|
||||
+ if (!put_opt6(inbuff, 4))
|
||||
return 0;
|
||||
start_opts = save_counter(-1);
|
||||
- state->xid = outmsgtypep[3] | outmsgtypep[2] << 8 | outmsgtypep[1] << 16;
|
||||
-
|
||||
+ state->xid = inbuff[3] | inbuff[2] << 8 | inbuff[1] << 16;
|
||||
+
|
||||
/* We're going to be linking tags from all context we use.
|
||||
mark them as unused so we don't link one twice and break the list */
|
||||
for (context_tmp = state->context; context_tmp; context_tmp = context_tmp->current)
|
||||
@@ -347,7 +348,7 @@ static int dhcp6_no_relay(struct state *
|
||||
(msg_type == DHCP6REQUEST || msg_type == DHCP6RENEW || msg_type == DHCP6RELEASE || msg_type == DHCP6DECLINE))
|
||||
|
||||
{
|
||||
- *outmsgtypep = DHCP6REPLY;
|
||||
+ outmsgtype = DHCP6REPLY;
|
||||
o1 = new_opt6(OPTION6_STATUS_CODE);
|
||||
put_opt6_short(DHCP6USEMULTI);
|
||||
put_opt6_string("Use multicast");
|
||||
@@ -619,11 +620,11 @@ static int dhcp6_no_relay(struct state *
|
||||
struct dhcp_netid *solicit_tags;
|
||||
struct dhcp_context *c;
|
||||
|
||||
- *outmsgtypep = DHCP6ADVERTISE;
|
||||
+ outmsgtype = DHCP6ADVERTISE;
|
||||
|
||||
if (opt6_find(state->packet_options, state->end, OPTION6_RAPID_COMMIT, 0))
|
||||
{
|
||||
- *outmsgtypep = DHCP6REPLY;
|
||||
+ outmsgtype = DHCP6REPLY;
|
||||
state->lease_allocate = 1;
|
||||
o = new_opt6(OPTION6_RAPID_COMMIT);
|
||||
end_opt6(o);
|
||||
@@ -809,7 +810,7 @@ static int dhcp6_no_relay(struct state *
|
||||
int start = save_counter(-1);
|
||||
|
||||
/* set reply message type */
|
||||
- *outmsgtypep = DHCP6REPLY;
|
||||
+ outmsgtype = DHCP6REPLY;
|
||||
state->lease_allocate = 1;
|
||||
|
||||
log6_quiet(state, "DHCPREQUEST", NULL, ignore ? _("ignored") : NULL);
|
||||
@@ -924,7 +925,7 @@ static int dhcp6_no_relay(struct state *
|
||||
int address_assigned = 0;
|
||||
|
||||
/* set reply message type */
|
||||
- *outmsgtypep = DHCP6REPLY;
|
||||
+ outmsgtype = DHCP6REPLY;
|
||||
|
||||
log6_quiet(state, msg_type == DHCP6RENEW ? "DHCPRENEW" : "DHCPREBIND", NULL, NULL);
|
||||
|
||||
@@ -1057,7 +1058,7 @@ static int dhcp6_no_relay(struct state *
|
||||
int good_addr = 0;
|
||||
|
||||
/* set reply message type */
|
||||
- *outmsgtypep = DHCP6REPLY;
|
||||
+ outmsgtype = DHCP6REPLY;
|
||||
|
||||
log6_quiet(state, "DHCPCONFIRM", NULL, NULL);
|
||||
|
||||
@@ -1121,7 +1122,7 @@ static int dhcp6_no_relay(struct state *
|
||||
log6_quiet(state, "DHCPINFORMATION-REQUEST", NULL, ignore ? _("ignored") : state->hostname);
|
||||
if (ignore)
|
||||
return 0;
|
||||
- *outmsgtypep = DHCP6REPLY;
|
||||
+ outmsgtype = DHCP6REPLY;
|
||||
tagif = add_options(state, 1);
|
||||
break;
|
||||
}
|
||||
@@ -1130,7 +1131,7 @@ static int dhcp6_no_relay(struct state *
|
||||
case DHCP6RELEASE:
|
||||
{
|
||||
/* set reply message type */
|
||||
- *outmsgtypep = DHCP6REPLY;
|
||||
+ outmsgtype = DHCP6REPLY;
|
||||
|
||||
log6_quiet(state, "DHCPRELEASE", NULL, NULL);
|
||||
|
||||
@@ -1195,7 +1196,7 @@ static int dhcp6_no_relay(struct state *
|
||||
case DHCP6DECLINE:
|
||||
{
|
||||
/* set reply message type */
|
||||
- *outmsgtypep = DHCP6REPLY;
|
||||
+ outmsgtype = DHCP6REPLY;
|
||||
|
||||
log6_quiet(state, "DHCPDECLINE", NULL, NULL);
|
||||
|
||||
@@ -1275,7 +1276,12 @@ static int dhcp6_no_relay(struct state *
|
||||
}
|
||||
|
||||
}
|
||||
-
|
||||
+
|
||||
+ /* Fill in the message type. Note that we store the offset,
|
||||
+ not a direct pointer, since the packet memory may have been
|
||||
+ reallocated. */
|
||||
+ ((unsigned char *)(daemon->outpacket.iov_base))[start_msg] = outmsgtype;
|
||||
+
|
||||
log_tags(tagif, state->xid);
|
||||
log6_opts(0, state->xid, daemon->outpacket.iov_base + start_opts, daemon->outpacket.iov_base + save_counter(-1));
|
||||
|
||||
Loading…
Reference in New Issue
Block a user