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Babel: Add MAC authentication support - update

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Some cleanups and bugfixes to the previous patch, including:

 - Fix rate limiting in index mismatch check

 - Fix missing BABEL_AUTH_INDEX_LEN in auth_tx_overhead computation

 - Fix missing auth_tx_overhead recalculation during reconfiguration

 - Fix pseudoheader construction in babel_auth_sign() (sport vs fport)

 - Fix typecasts for ptrdiffs in log messages

 - Make auth log messages similar to corresponding RIP/OSPF ones

 - Change auth log messages for events that happen during regular
   operation to debug messages

 - Switch meaning of babel_auth_check*() functions for consistency
   with corresponding RIP/OSPF ones

 - Remove requirement for min/max key length, only those required by
   given MAC code are enforced
This commit is contained in:
Ondrej Zajicek (work) 2021-06-06 15:22:59 +02:00
parent b218a28f61
commit b174cc0abc
5 changed files with 205 additions and 198 deletions
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9
doc/bird.sgml
View file

@ -1827,8 +1827,8 @@ protocol babel [<name>] {
accept to "&lt;date&gt;";
from "&lt;date&gt;";
to "&lt;date&gt;";
algorithm ( hmac sha1 | hmac sha256 | hmac sha384 | hmac
sha512 | blake2s | blake2b );
algorithm ( hmac sha1 | hmac sha256 | hmac sha384 |
hmac sha512 | blake2s128 | blake2s256 | blake2b256 | blake2b512 );
};
};
}
@ -1932,13 +1932,12 @@ protocol babel [<name>] {
authentication is selected, a key must be specified with the
<cf/password/ configuration option. Default: none.
<tag><label id="babel-password">password "<m/text/"</tag> Specifies a
password used for authentication. See the <ref id="proto-pass"
<tag><label id="babel-password">password "<m/text/"</tag>
Specifies a password used for authentication. See the <ref id="proto-pass"
name="password"> common option for a detailed description. The Babel
protocol will only accept HMAC-based algorithms or one of the Blake
algorithms, and the length of the supplied password string must match the
key size used by the selected algorithm.
</descrip>
<sect1>Attributes

104
proto/babel/babel.c
View file

@ -1428,94 +1428,113 @@ babel_auth_init_neighbor(struct babel_neighbor *n)
}
static void
babel_auth_send_challenge(struct babel_iface *ifa, struct babel_neighbor *n)
babel_auth_send_challenge_request(struct babel_iface *ifa, struct babel_neighbor *n)
{
struct babel_proto *p = ifa->proto;
union babel_msg msg = {};
TRACE(D_PACKETS, "Sending AUTH challenge to %I on %s",
TRACE(D_PACKETS, "Sending challenge request to %I on %s",
n->addr, ifa->ifname);
random_bytes(n->auth_nonce, BABEL_AUTH_NONCE_LEN);
n->auth_nonce_expiry = current_time() + BABEL_AUTH_CHALLENGE_TIMEOUT;
n->auth_next_challenge = current_time() + BABEL_AUTH_CHALLENGE_INTERVAL;
msg.type = BABEL_TLV_CHALLENGE_REQ;
msg.type = BABEL_TLV_CHALLENGE_REQUEST;
msg.challenge.nonce_len = BABEL_AUTH_NONCE_LEN;
msg.challenge.nonce = n->auth_nonce;
babel_send_unicast(&msg, ifa, n->addr);
}
static void
babel_auth_send_challenge_reply(struct babel_iface *ifa, struct babel_neighbor *n, struct babel_msg_auth *rcv)
{
struct babel_proto *p = ifa->proto;
union babel_msg msg = {};
TRACE(D_PACKETS, "Sending challenge reply to %I on %s",
n->addr, ifa->ifname);
n->auth_next_challenge_reply = current_time() + BABEL_AUTH_CHALLENGE_INTERVAL;
msg.type = BABEL_TLV_CHALLENGE_REPLY;
msg.challenge.nonce_len = rcv->challenge_len;
msg.challenge.nonce = rcv->challenge;
babel_send_unicast(&msg, ifa, n->addr);
}
int
babel_auth_check_pc(struct babel_iface *ifa, struct babel_msg_auth *msg)
{
struct babel_proto *p = ifa->proto;
struct babel_neighbor *n;
TRACE(D_PACKETS, "Handling MAC check from %I on %s",
msg->sender, ifa->ifname);
/* We create the neighbour entry at this point because it makes it easier to
/*
* We create the neighbour entry at this point because it makes it easier to
* rate limit challenge replies; this is explicitly allowed by the spec (see
* Section 4.3).
* Section 4.3).
*/
n = babel_get_neighbor(ifa, msg->sender);
if (msg->challenge_seen && n->auth_next_challenge_reply <= current_time())
{
union babel_msg resp = {};
TRACE(D_PACKETS, "Sending MAC challenge response to %I", msg->sender);
resp.type = BABEL_TLV_CHALLENGE_REPLY;
resp.challenge.nonce_len = msg->challenge_len;
resp.challenge.nonce = msg->challenge;
n->auth_next_challenge_reply = current_time() + BABEL_AUTH_CHALLENGE_INTERVAL;
babel_send_unicast(&resp, ifa, msg->sender);
}
/* (3b) Handle challenge request */
if (msg->challenge_seen && (n->auth_next_challenge_reply <= current_time()))
babel_auth_send_challenge_reply(ifa, n, msg);
if (msg->index_len > BABEL_AUTH_INDEX_LEN || !msg->pc_seen)
/* (4a) If PC TLV is missing, drop the packet */
if (!msg->pc_seen)
{
LOG_PKT_AUTH("Invalid index or no PC from %I on %s",
LOG_PKT_AUTH("Authentication failed for %I on %s - missing or invalid PC",
msg->sender, ifa->ifname);
return 1;
return 0;
}
/* On successful challenge, update PC and index to current values */
/* (4b) On successful challenge, update PC and index to current values */
if (msg->challenge_reply_seen &&
n->auth_nonce_expiry &&
n->auth_nonce_expiry >= current_time() &&
(n->auth_nonce_expiry > current_time()) &&
!memcmp(msg->challenge_reply, n->auth_nonce, BABEL_AUTH_NONCE_LEN))
{
n->auth_index_len = msg->index_len;
memcpy(n->auth_index, msg->index, msg->index_len);
n->auth_pc = msg->pc;
}
/* If index differs, send challenge */
if ((n->auth_index_len != msg->index_len ||
memcmp(n->auth_index, msg->index, msg->index_len)) &&
n->auth_next_challenge <= current_time())
{
LOG_PKT_AUTH("Index mismatch from %I on %s; sending challenge",
msg->sender, ifa->ifname);
babel_auth_send_challenge(ifa, n);
n->auth_pc = msg->pc;
n->auth_expiry = current_time() + BABEL_AUTH_NEIGHBOR_TIMEOUT;
n->auth_passed = 1;
return 1;
}
/* Index matches; only accept if PC is greater than last */
/* (5) If index differs, send challenge and drop the packet */
if ((n->auth_index_len != msg->index_len) ||
memcmp(n->auth_index, msg->index, msg->index_len))
{
TRACE(D_PACKETS, "Index mismatch for packet from %I via %s",
msg->sender, ifa->ifname);
if (n->auth_next_challenge <= current_time())
babel_auth_send_challenge_request(ifa, n);
return 0;
}
/* (6) Index matches; only accept if PC is greater than last */
if (n->auth_pc >= msg->pc)
{
LOG_PKT_AUTH("Packet counter too low from %I on %s",
msg->sender, ifa->ifname);
return 1;
LOG_PKT_AUTH("Authentication failed for %I on %s - "
"lower packet counter (rcv %u, old %u)",
msg->sender, ifa->ifname, msg->pc, n->auth_pc);
return 0;
}
n->auth_pc = msg->pc;
n->auth_expiry = current_time() + BABEL_AUTH_NEIGHBOR_TIMEOUT;
n->auth_passed = 1;
return 0;
return 1;
}
/*
* Babel interfaces
*/
@ -1854,7 +1873,9 @@ babel_reconfigure_iface(struct babel_proto *p, struct babel_iface *ifa, struct b
ifa->next_hop_ip4 = ipa_nonzero(new->next_hop_ip4) ? new->next_hop_ip4 : addr4;
ifa->next_hop_ip6 = ipa_nonzero(new->next_hop_ip6) ? new->next_hop_ip6 : ifa->addr;
if (new->auth_type != BABEL_AUTH_NONE && old->auth_type != new->auth_type)
babel_iface_update_buffers(ifa);
if ((new->auth_type != BABEL_AUTH_NONE) && (new->auth_type != old->auth_type))
babel_auth_reset_index(ifa);
if (ipa_zero(ifa->next_hop_ip4) && p->ip4_channel)
@ -1866,9 +1887,6 @@ babel_reconfigure_iface(struct babel_proto *p, struct babel_iface *ifa, struct b
if (ifa->next_regular > (current_time() + new->update_interval))
ifa->next_regular = current_time() + (random() % new->update_interval);
if ((new->tx_length != old->tx_length) || (new->rx_buffer != old->rx_buffer))
babel_iface_update_buffers(ifa);
if (new->check_link != old->check_link)
babel_iface_update_state(ifa);

7
proto/babel/babel.h
View file

@ -61,8 +61,9 @@
#define BABEL_OVERHEAD (IP6_HEADER_LENGTH+UDP_HEADER_LENGTH)
#define BABEL_MIN_MTU (512 + BABEL_OVERHEAD)
#define BABEL_AUTH_NONE 0
#define BABEL_AUTH_NONE 0
#define BABEL_AUTH_MAC 1
#define BABEL_AUTH_NONCE_LEN 10 /* we send 80 bit nonces */
#define BABEL_AUTH_MAX_NONCE_LEN 192 /* max allowed by spec */
#define BABEL_AUTH_INDEX_LEN 32 /* max size in spec */
@ -82,9 +83,9 @@ enum babel_tlv_type {
BABEL_TLV_UPDATE = 8,
BABEL_TLV_ROUTE_REQUEST = 9,
BABEL_TLV_SEQNO_REQUEST = 10,
BABEL_TLV_MAC = 16,
BABEL_TLV_MAC = 16,
BABEL_TLV_PC = 17,
BABEL_TLV_CHALLENGE_REQ = 18,
BABEL_TLV_CHALLENGE_REQUEST = 18,
BABEL_TLV_CHALLENGE_REPLY = 19,
BABEL_TLV_MAX
};

22
proto/babel/config.Y
View file

@ -103,26 +103,24 @@ babel_iface_finish:
{
struct password_item *pass;
uint len = 0, i = 0;
WALK_LIST(pass, *BABEL_IFACE->passwords)
{
/* Set default crypto algorithm (HMAC-SHA256) */
if (!pass->alg)
pass->alg = ALG_HMAC_SHA256;
if (pass->alg & ALG_HMAC) {
if (pass->length < mac_type_length(pass->alg) ||
pass->length > mac_type_block_size(pass->alg))
cf_error("key length %d is not between output size %d and block size %d for algorithm %s",
pass->length, mac_type_length(pass->alg),
mac_type_block_size(pass->alg), mac_type_name(pass->alg));
} else if (!(pass->alg == ALG_BLAKE2S_128 || pass->alg == ALG_BLAKE2S_256 ||
pass->alg == ALG_BLAKE2B_256 || pass->alg == ALG_BLAKE2B_512)) {
cf_error("Only HMAC and Blake algorithms are supported");
}
if (!((pass->alg & ALG_HMAC) ||
(pass->alg == ALG_BLAKE2S_128) ||
(pass->alg == ALG_BLAKE2S_256) ||
(pass->alg == ALG_BLAKE2B_256) ||
(pass->alg == ALG_BLAKE2B_512)))
cf_error("Only HMAC and Blake2 algorithms are supported");
len += mac_type_length(pass->alg);
i++;
}
BABEL_IFACE->mac_num_keys = i;
BABEL_IFACE->mac_total_len = len;
}
@ -146,9 +144,9 @@ babel_iface_item:
| NEXT HOP IPV4 ipa { BABEL_IFACE->next_hop_ip4 = $4; if (!ipa_is_ip4($4)) cf_error("Must be an IPv4 address"); }
| NEXT HOP IPV6 ipa { BABEL_IFACE->next_hop_ip6 = $4; if (!ipa_is_ip6($4)) cf_error("Must be an IPv6 address"); }
| AUTHENTICATION NONE { BABEL_IFACE->auth_type = BABEL_AUTH_NONE; }
| AUTHENTICATION MAC { BABEL_IFACE->auth_type = BABEL_AUTH_MAC; }
| AUTHENTICATION MAC { BABEL_IFACE->auth_type = BABEL_AUTH_MAC; BABEL_IFACE->auth_permissive = 0; }
| AUTHENTICATION MAC PERMISSIVE { BABEL_IFACE->auth_type = BABEL_AUTH_MAC; BABEL_IFACE->auth_permissive = 1; }
| password_list { }
| password_list
;
babel_iface_opts:

261
proto/babel/packets.c
View file

@ -13,6 +13,7 @@
#include "babel.h"
#include "lib/mac.h"
struct babel_pkt_header {
u8 magic;
u8 version;
@ -112,6 +113,12 @@ struct babel_subtlv_source_prefix {
u8 addr[0];
} PACKED;
struct babel_tlv_mac {
u8 type;
u8 length;
u8 mac[0];
} PACKED;
struct babel_tlv_pc {
u8 type;
u8 length;
@ -119,19 +126,13 @@ struct babel_tlv_pc {
u8 index[0];
} PACKED;
struct babel_tlv_mac {
u8 type;
u8 length;
u8 mac[0];
} PACKED;
struct babel_tlv_challenge {
u8 type;
u8 length;
u8 nonce[0];
} PACKED;
struct babel_mac_pseudohdr {
struct babel_mac_pseudoheader {
u8 src_addr[16];
u16 src_port;
u8 dst_addr[16];
@ -234,7 +235,7 @@ struct babel_write_state {
if ((loop_pos > end) || (loop_pos + tlv->length > end)) \
{ \
LOG_PKT("Bad TLV from %I via %s type %d pos %d - framing error", \
saddr, ifname, tlv->type, (byte *)tlv - (byte *)start); \
saddr, ifname, tlv->type, (int) ((byte *)tlv - (byte *)start)); \
frame_err = 1; \
break; \
}
@ -306,11 +307,13 @@ put_ip6_ll(void *p, ip6_addr addr)
put_u32(p+4, _I3(addr));
}
/*
* Authentication-related functions
*/
uint babel_auth_write_challenge(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len);
int babel_auth_add_tlvs(struct babel_iface *ifa, struct babel_tlv *tlv, int max_len);
int babel_auth_add_tlvs(struct babel_iface *ifa, struct babel_tlv *tlv, uint max_len);
int babel_auth_sign(struct babel_iface *ifa, ip_addr dest);
int babel_auth_check(struct babel_iface *ifa,
ip_addr saddr, u16 sport,
@ -395,15 +398,17 @@ static const struct babel_tlv_data tlv_data[BABEL_TLV_MAX] = {
babel_write_seqno_request,
babel_handle_seqno_request
},
[BABEL_TLV_CHALLENGE_REQ] = {
sizeof(struct babel_tlv),
[BABEL_TLV_CHALLENGE_REQUEST] = {
sizeof(struct babel_tlv_challenge),
NULL,
babel_auth_write_challenge,
NULL
},
[BABEL_TLV_CHALLENGE_REPLY] = {
sizeof(struct babel_tlv),
sizeof(struct babel_tlv_challenge),
NULL,
babel_auth_write_challenge,
NULL
},
};
@ -421,7 +426,7 @@ static const struct babel_tlv_data source_prefix_tlv_data = {
static const struct babel_tlv_data *get_packet_subtlv_data(u8 type)
{
switch(type)
switch (type)
{
case BABEL_SUBTLV_SOURCE_PREFIX:
return &source_prefix_tlv_data;
@ -1128,7 +1133,7 @@ babel_read_source_prefix(struct babel_tlv *hdr, union babel_msg *msg,
if (tlv->plen == 0)
return PARSE_ERROR;
switch(msg->type)
switch (msg->type)
{
case BABEL_TLV_UPDATE:
/* Wildcard updates with source prefix MUST be silently ignored */
@ -1278,6 +1283,7 @@ babel_write_tlv(struct babel_tlv *hdr,
return tlv_data[msg->type].write_tlv(hdr, msg, state, max_len);
}
/*
* Packet RX/TX functions
*/
@ -1343,7 +1349,7 @@ babel_write_queue(struct babel_iface *ifa, list *queue)
sl_free(p->msg_slab, msg);
}
pos += babel_auth_add_tlvs(ifa, (struct babel_tlv *) pos, end-pos);
pos += babel_auth_add_tlvs(ifa, (struct babel_tlv *) pos, end - pos);
uint plen = pos - (byte *) pkt;
put_u16(&pkt->length, plen - sizeof(struct babel_pkt_header));
@ -1423,7 +1429,7 @@ babel_enqueue(union babel_msg *msg, struct babel_iface *ifa)
/**
* babel_process_packet - process incoming data packet
* @ifa: Interface packet was received on.
* @ifa: Interface packet was received on
* @pkt: Pointer to the packet data
* @len: Length of received packet
* @saddr: Address of packet sender
@ -1483,7 +1489,7 @@ babel_process_packet(struct babel_iface *ifa,
TRACE(D_PACKETS, "Packet received from %I via %s",
saddr, ifa->iface->name);
if (babel_auth_check(ifa, saddr, sport, daddr, dport, pkt, end, len-plen))
if (!babel_auth_check(ifa, saddr, sport, daddr, dport, pkt, end, len - plen))
return;
init_list(&msgs);
@ -1506,7 +1512,7 @@ babel_process_packet(struct babel_iface *ifa,
else /* PARSE_ERROR */
{
LOG_PKT("Bad TLV from %I via %s type %d pos %d - parse error",
saddr, ifa->iface->name, tlv->type, (byte *)tlv - (byte *)pkt);
saddr, ifa->iface->name, tlv->type, (int) ((byte *)tlv - (byte *)pkt));
sl_free(p->msg_slab, msg);
break;
}
@ -1638,15 +1644,21 @@ babel_read_pc(struct babel_tlv *hdr, union babel_msg *m UNUSED,
{
struct babel_tlv_pc *tlv = (void *) hdr;
if (!state->auth.pc_seen)
{
state->auth.pc_seen = 1;
state->auth.pc = get_u32(&tlv->pc);
state->auth.index_len = TLV_OPT_LENGTH(tlv);
state->auth.index = tlv->index;
}
/* RFC 8967 4.3 (3) - If multiple PCs are found, only the first one is used */
if (state->auth.pc_seen)
return PARSE_IGNORE;
return PARSE_IGNORE;
uint index_len = TLV_OPT_LENGTH(tlv);
if (index_len > BABEL_AUTH_INDEX_LEN)
return PARSE_IGNORE;
state->auth.pc = get_u32(&tlv->pc);
state->auth.pc_seen = 1;
state->auth.index_len = index_len;
state->auth.index = tlv->index;
state->current_tlv_endpos += index_len;
return PARSE_SUCCESS;
}
static const struct babel_tlv_data pc_tlv_data = {
@ -1661,20 +1673,18 @@ babel_read_challenge_req(struct babel_tlv *hdr, union babel_msg *m UNUSED,
struct babel_tlv_challenge *tlv = (void *) hdr;
if (!state->is_unicast)
{
DBG("Ignoring non-unicast challenge request from %I\n", state->saddr);
return PARSE_IGNORE;
}
if (tlv->length > BABEL_AUTH_MAX_NONCE_LEN)
return PARSE_IGNORE;
state->auth.challenge_len = tlv->length;
if (state->auth.challenge_len)
memcpy(state->auth.challenge, tlv->nonce, state->auth.challenge_len);
uint nonce_len = TLV_OPT_LENGTH(tlv);
if (nonce_len > BABEL_AUTH_MAX_NONCE_LEN)
return PARSE_IGNORE;
state->auth.challenge_len = nonce_len;
bmemcpy(state->auth.challenge, tlv->nonce, nonce_len);
state->auth.challenge_seen = 1;
state->current_tlv_endpos += nonce_len;
return PARSE_IGNORE;
return PARSE_SUCCESS;
}
static const struct babel_tlv_data challenge_req_tlv_data = {
@ -1688,13 +1698,18 @@ babel_read_challenge_reply(struct babel_tlv *hdr, union babel_msg *m UNUSED,
{
struct babel_tlv_challenge *tlv = (void *) hdr;
if (tlv->length != BABEL_AUTH_NONCE_LEN || state->auth.challenge_reply_seen)
if (state->auth.challenge_reply_seen)
return PARSE_IGNORE;
state->auth.challenge_reply_seen = 1;
memcpy(state->auth.challenge_reply, tlv->nonce, BABEL_AUTH_NONCE_LEN);
uint nonce_len = TLV_OPT_LENGTH(tlv);
if (nonce_len != BABEL_AUTH_NONCE_LEN)
return PARSE_IGNORE;
return PARSE_IGNORE;
memcpy(state->auth.challenge_reply, tlv->nonce, BABEL_AUTH_NONCE_LEN);
state->auth.challenge_reply_seen = 1;
state->current_tlv_endpos += nonce_len;
return PARSE_SUCCESS;
}
static const struct babel_tlv_data challenge_reply_tlv_data = {
@ -1705,11 +1720,11 @@ static const struct babel_tlv_data challenge_reply_tlv_data = {
static const struct babel_tlv_data *
get_auth_tlv_data(u8 type)
{
switch(type)
switch (type)
{
case BABEL_TLV_PC:
return &pc_tlv_data;
case BABEL_TLV_CHALLENGE_REQ:
case BABEL_TLV_CHALLENGE_REQUEST:
return &challenge_req_tlv_data;
case BABEL_TLV_CHALLENGE_REPLY:
return &challenge_reply_tlv_data;
@ -1720,7 +1735,7 @@ get_auth_tlv_data(u8 type)
uint
babel_auth_write_challenge(struct babel_tlv *hdr, union babel_msg *m,
struct babel_write_state *state UNUSED,uint max_len)
struct babel_write_state *state UNUSED, uint max_len)
{
struct babel_tlv_challenge *tlv = (void *) hdr;
struct babel_msg_challenge *msg = &m->challenge;
@ -1731,36 +1746,28 @@ babel_auth_write_challenge(struct babel_tlv *hdr, union babel_msg *m,
return 0;
TLV_HDR(tlv, msg->type, len);
memcpy(tlv->nonce, msg->nonce, msg->nonce_len);
bmemcpy(tlv->nonce, msg->nonce, msg->nonce_len);
return len;
}
static int
babel_mac_hash(struct password_item *pass,
struct babel_mac_pseudohdr *phdr,
byte *pkt, uint pkt_len,
byte *buf, uint *buf_len)
static void
babel_mac_fill(struct password_item *pass,
struct babel_mac_pseudoheader *phdr,
byte *pkt, uint pkt_len,
byte *mac)
{
struct mac_context ctx;
if (mac_type_length(pass->alg) > *buf_len)
return 1;
mac_init(&ctx, pass->alg, pass->password, pass->length);
mac_update(&ctx, (byte *)phdr, sizeof(*phdr));
mac_update(&ctx, (byte *)pkt, pkt_len);
*buf_len = mac_get_length(&ctx);
memcpy(buf, mac_final(&ctx), *buf_len);
memcpy(mac, mac_final(&ctx), mac_get_length(&ctx));
mac_cleanup(&ctx);
return 0;
}
static void
babel_mac_build_phdr(struct babel_mac_pseudohdr *phdr,
babel_mac_build_phdr(struct babel_mac_pseudoheader *phdr,
ip_addr saddr, u16 sport,
ip_addr daddr, u16 dport)
{
@ -1778,61 +1785,56 @@ babel_auth_check_mac(struct babel_iface *ifa, byte *pkt,
ip_addr saddr, u16 sport,
ip_addr daddr, u16 dport)
{
uint hash_len = (uint)(trailer - pkt);
struct babel_proto *p = ifa->proto;
uint pkt_len = (uint)(trailer - pkt);
byte *end = trailer + trailer_len;
btime now_ = current_real_time();
struct babel_mac_pseudohdr phdr;
struct password_item *pass;
struct babel_tlv *tlv;
if (trailer_len < sizeof(*tlv))
if (trailer_len < sizeof(struct babel_tlv))
{
LOG_PKT_AUTH("No MAC signature on packet from %I on %s",
LOG_PKT_AUTH("Authentication failed for %I on %s - no MAC signature",
saddr, ifa->ifname);
return 1;
return 0;
}
struct babel_mac_pseudoheader phdr;
babel_mac_build_phdr(&phdr, saddr, sport, daddr, dport);
struct password_item *pass;
WALK_LIST(pass, *ifa->cf->passwords)
{
byte mac_res[MAX_HASH_SIZE];
uint mac_len = MAX_HASH_SIZE;
u8 frame_err = 0;
byte mac[MAX_HASH_SIZE];
uint mac_len = mac_type_length(pass->alg);
uint frame_err = 0;
if (pass->accfrom > now_ || pass->accto < now_)
continue;
if (babel_mac_hash(pass, &phdr,
pkt, hash_len,
mac_res, &mac_len))
continue;
babel_mac_fill(pass, &phdr, pkt, pkt_len, mac);
WALK_TLVS((void *)trailer, end, tlv, frame_err, saddr, ifa->ifname)
struct babel_tlv *tlv0;
WALK_TLVS((void *)trailer, end, tlv0, frame_err, saddr, ifa->ifname)
{
struct babel_tlv_mac *mac = (void *)tlv;
struct babel_tlv_mac *tlv = (void *)tlv0;
if (tlv->type != BABEL_TLV_MAC)
continue;
if (tlv->length == mac_len && !memcmp(mac->mac, mac_res, mac_len))
return 0;
if ((TLV_OPT_LENGTH(tlv) == mac_len) && !memcmp(tlv->mac, mac, mac_len))
return 1;
DBG("MAC mismatch key id %d pos %d len %d/%d\n",
pass->id, (byte *)tlv - (byte *)pkt, mac_len, tlv->length);
pass->id, (int) ((byte *)tlv - (byte *)pkt), mac_len, tlv->length);
}
WALK_TLVS_END;
if (frame_err) {
DBG("MAC trailer TLV framing error\n");
return 1;
}
if (frame_err)
return 0;
}
LOG_PKT_AUTH("No MAC key matching packet from %I found on %s",
LOG_PKT_AUTH("Authentication failed for %I on %s - no matching key",
saddr, ifa->ifname);
return 1;
return 0;
}
/**
@ -1859,7 +1861,7 @@ babel_auth_check(struct babel_iface *ifa,
struct babel_pkt_header *pkt,
byte *trailer, uint trailer_len)
{
u8 frame_err UNUSED = 0;
uint frame_err UNUSED = 0;
struct babel_proto *p = ifa->proto;
struct babel_tlv *tlv;
@ -1868,25 +1870,25 @@ babel_auth_check(struct babel_iface *ifa,
.proto = p,
.ifa = ifa,
.saddr = saddr,
.is_unicast = !(ipa_classify(daddr) & IADDR_MULTICAST),
.is_unicast = !(ipa_classify(daddr) & IADDR_MULTICAST),
.auth = {
.sender = saddr,
},
};
if (ifa->cf->auth_type == BABEL_AUTH_NONE)
return 0;
return 1;
TRACE(D_PACKETS, "Checking packet authentication signature");
if (babel_auth_check_mac(ifa, (byte *)pkt,
if (!babel_auth_check_mac(ifa, (byte *)pkt,
trailer, trailer_len,
saddr, sport,
daddr, dport))
goto fail;
/* MAC verified; parse packet to check packet counter and challenge */
WALK_TLVS(FIRST_TLV(pkt), trailer, tlv, frame_err, saddr, ifa->iface->name)
WALK_TLVS(FIRST_TLV(pkt), trailer, tlv, frame_err, saddr, ifa->ifname)
{
union babel_msg msg;
enum parse_result res;
@ -1894,26 +1896,26 @@ babel_auth_check(struct babel_iface *ifa,
res = babel_read_tlv(tlv, &msg, &state);
if (res == PARSE_ERROR)
{
LOG_PKT_AUTH("Bad TLV from %I via %s type %d pos %d - parse error",
saddr, ifa->iface->name, tlv->type, (byte *)tlv - (byte *)pkt);
LOG_PKT("Bad TLV from %I via %s type %d pos %d - parse error",
saddr, ifa->ifname, tlv->type, (int) ((byte *)tlv - (byte *)pkt));
goto fail;
}
}
WALK_TLVS_END;
if (babel_auth_check_pc(ifa, &state.auth))
if (!babel_auth_check_pc(ifa, &state.auth))
goto fail;
TRACE(D_PACKETS, "Packet from %I via %s authenticated successfully",
saddr, ifa->ifname);
return 0;
return 1;
fail:
LOG_PKT_AUTH("Packet from %I via %s failed authentication%s",
TRACE(D_PACKETS, "Packet from %I via %s failed authentication%s",
saddr, ifa->ifname,
ifa->cf->auth_permissive ? " but accepted in permissive mode" : "");
return !ifa->cf->auth_permissive;
return ifa->cf->auth_permissive;
}
/**
@ -1927,17 +1929,17 @@ fail:
* counter TLV that must be included in every packet.
*/
int
babel_auth_add_tlvs(struct babel_iface *ifa, struct babel_tlv *tlv, int max_len)
babel_auth_add_tlvs(struct babel_iface *ifa, struct babel_tlv *hdr, uint max_len)
{
struct babel_proto *p = ifa->proto;
struct babel_tlv_pc *msg;
int len;
struct babel_tlv_pc *tlv;
uint len;
if (ifa->cf->auth_type == BABEL_AUTH_NONE)
return 0;
msg = (void *)tlv;
len = sizeof(*msg) + BABEL_AUTH_INDEX_LEN;
tlv = (void *) hdr;
len = sizeof(struct babel_tlv_pc) + BABEL_AUTH_INDEX_LEN;
max_len += ifa->auth_tx_overhead;
if (len > max_len)
@ -1947,10 +1949,9 @@ babel_auth_add_tlvs(struct babel_iface *ifa, struct babel_tlv *tlv, int max_len)
return 0;
}
msg->type = BABEL_TLV_PC;
msg->length = len - sizeof(struct babel_tlv);
put_u32(&msg->pc, ifa->auth_pc++);
memcpy(msg->index, ifa->auth_index, BABEL_AUTH_INDEX_LEN);
TLV_HDR(tlv, BABEL_TLV_PC, len);
put_u32(&tlv->pc, ifa->auth_pc++);
memcpy(tlv->index, ifa->auth_index, BABEL_AUTH_INDEX_LEN);
/* Reset index on overflow to 0 */
if (!ifa->auth_pc)
@ -1971,58 +1972,48 @@ int
babel_auth_sign(struct babel_iface *ifa, ip_addr dest)
{
struct babel_proto *p = ifa->proto;
struct babel_mac_pseudohdr phdr;
struct babel_pkt_header *hdr;
struct password_item *pass;
int tot_len = 0, i = 0;
struct babel_tlv *tlv;
sock *sk = ifa->sk;
byte *pos, *end;
btime now_;
int len;
if (ifa->cf->auth_type == BABEL_AUTH_NONE)
return 0;
hdr = (void *) sk->tbuf;
len = get_u16(&hdr->length) + sizeof(struct babel_pkt_header);
struct babel_pkt_header *hdr = (void *) sk->tbuf;
int len = get_u16(&hdr->length) + sizeof(struct babel_pkt_header);
pos = (byte *)hdr + len;
end = (byte *)hdr + ifa->tx_length + ifa->auth_tx_overhead;
tlv = (void *)pos;
now_ = current_real_time();
byte *pkt = (byte *) hdr;
byte *pos = pkt + len;
byte *end = pkt + ifa->tx_length + ifa->auth_tx_overhead;
btime now_ = current_real_time();
babel_mac_build_phdr(&phdr, sk->saddr, sk->fport, dest, sk->dport);
struct babel_mac_pseudoheader phdr;
babel_mac_build_phdr(&phdr, sk->saddr, sk->sport, dest, sk->dport);
struct password_item *pass;
WALK_LIST(pass, *ifa->cf->passwords)
{
struct babel_tlv_mac *msg = (void *)tlv;
uint buf_len = (uint) (end - (byte *)msg - sizeof(*msg));
struct babel_tlv_mac *tlv = (void *) pos;
uint tlv_len = sizeof(struct babel_tlv_mac) + mac_type_length(pass->alg);
if (pass->genfrom > now_ || pass->gento < now_)
continue;
if (babel_mac_hash(pass, &phdr,
(byte *)hdr, len,
msg->mac, &buf_len))
if (pos + tlv_len > end)
{
LOG_WARN("Insufficient space for MAC signatures on iface %s dest %I",
ifa->ifname, dest);
LOG_WARN("Insufficient space for MAC signatures on iface %s dst %I (%d/%d)",
ifa->ifname, dest, tlv_len, (int) (end-pos));
break;
}
msg->type = BABEL_TLV_MAC;
msg->length = buf_len;
TLV_HDR(tlv, BABEL_TLV_MAC, tlv_len);
babel_mac_fill(pass, &phdr, pkt, len, tlv->mac);
tlv = NEXT_TLV(tlv);
tot_len += buf_len + sizeof(*msg);
i++;
pos += tlv_len;
}
DBG("Added %d MAC signatures (%d bytes) on ifa %s for dest %I\n",
i, tot_len, ifa->ifname, dest);
DBG("Added MAC signatures (%d bytes) on ifa %s for dest %I\n",
tot_len, ifa->ifname, dest);
return tot_len;
return pos - (pkt + len);
}
/**
@ -2041,7 +2032,7 @@ babel_auth_set_tx_overhead(struct babel_iface *ifa)
return;
}
ifa->auth_tx_overhead = (sizeof(struct babel_tlv_pc) +
ifa->auth_tx_overhead = (sizeof(struct babel_tlv_pc) + BABEL_AUTH_INDEX_LEN +
sizeof(struct babel_tlv_mac) * ifa->cf->mac_num_keys +
ifa->cf->mac_total_len);
ifa->tx_length -= ifa->auth_tx_overhead;