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

102
proto/babel/babel.c
View file

@ -1428,94 +1428,113 @@ babel_auth_init_neighbor(struct babel_neighbor *n)
} }
static void 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; struct babel_proto *p = ifa->proto;
union babel_msg msg = {}; 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); n->addr, ifa->ifname);
random_bytes(n->auth_nonce, BABEL_AUTH_NONCE_LEN); random_bytes(n->auth_nonce, BABEL_AUTH_NONCE_LEN);
n->auth_nonce_expiry = current_time() + BABEL_AUTH_CHALLENGE_TIMEOUT; n->auth_nonce_expiry = current_time() + BABEL_AUTH_CHALLENGE_TIMEOUT;
n->auth_next_challenge = current_time() + BABEL_AUTH_CHALLENGE_INTERVAL; 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_len = BABEL_AUTH_NONCE_LEN;
msg.challenge.nonce = n->auth_nonce; msg.challenge.nonce = n->auth_nonce;
babel_send_unicast(&msg, ifa, n->addr); 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 int
babel_auth_check_pc(struct babel_iface *ifa, struct babel_msg_auth *msg) babel_auth_check_pc(struct babel_iface *ifa, struct babel_msg_auth *msg)
{ {
struct babel_proto *p = ifa->proto; struct babel_proto *p = ifa->proto;
struct babel_neighbor *n; 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 * 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); n = babel_get_neighbor(ifa, msg->sender);
if (msg->challenge_seen && n->auth_next_challenge_reply <= current_time()) /* (3b) Handle challenge request */
{ if (msg->challenge_seen && (n->auth_next_challenge_reply <= current_time()))
union babel_msg resp = {}; babel_auth_send_challenge_reply(ifa, n, msg);
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);
}
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); 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 && 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)) !memcmp(msg->challenge_reply, n->auth_nonce, BABEL_AUTH_NONCE_LEN))
{ {
n->auth_index_len = msg->index_len; n->auth_index_len = msg->index_len;
memcpy(n->auth_index, msg->index, msg->index_len); memcpy(n->auth_index, msg->index, msg->index_len);
n->auth_pc = msg->pc;
}
/* If index differs, send challenge */ n->auth_pc = msg->pc;
if ((n->auth_index_len != msg->index_len || n->auth_expiry = current_time() + BABEL_AUTH_NEIGHBOR_TIMEOUT;
memcmp(n->auth_index, msg->index, msg->index_len)) && n->auth_passed = 1;
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);
return 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) if (n->auth_pc >= msg->pc)
{ {
LOG_PKT_AUTH("Packet counter too low from %I on %s", LOG_PKT_AUTH("Authentication failed for %I on %s - "
msg->sender, ifa->ifname); "lower packet counter (rcv %u, old %u)",
return 1; msg->sender, ifa->ifname, msg->pc, n->auth_pc);
return 0;
} }
n->auth_pc = msg->pc; n->auth_pc = msg->pc;
n->auth_expiry = current_time() + BABEL_AUTH_NEIGHBOR_TIMEOUT; n->auth_expiry = current_time() + BABEL_AUTH_NEIGHBOR_TIMEOUT;
n->auth_passed = 1; n->auth_passed = 1;
return 0;
return 1;
} }
/* /*
* Babel interfaces * 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_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; 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); babel_auth_reset_index(ifa);
if (ipa_zero(ifa->next_hop_ip4) && p->ip4_channel) 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)) if (ifa->next_regular > (current_time() + new->update_interval))
ifa->next_regular = current_time() + (random() % 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) if (new->check_link != old->check_link)
babel_iface_update_state(ifa); babel_iface_update_state(ifa);

3
proto/babel/babel.h
View file

@ -63,6 +63,7 @@
#define BABEL_AUTH_NONE 0 #define BABEL_AUTH_NONE 0
#define BABEL_AUTH_MAC 1 #define BABEL_AUTH_MAC 1
#define BABEL_AUTH_NONCE_LEN 10 /* we send 80 bit nonces */ #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_MAX_NONCE_LEN 192 /* max allowed by spec */
#define BABEL_AUTH_INDEX_LEN 32 /* max size in spec */ #define BABEL_AUTH_INDEX_LEN 32 /* max size in spec */
@ -84,7 +85,7 @@ enum babel_tlv_type {
BABEL_TLV_SEQNO_REQUEST = 10, BABEL_TLV_SEQNO_REQUEST = 10,
BABEL_TLV_MAC = 16, BABEL_TLV_MAC = 16,
BABEL_TLV_PC = 17, BABEL_TLV_PC = 17,
BABEL_TLV_CHALLENGE_REQ = 18, BABEL_TLV_CHALLENGE_REQUEST = 18,
BABEL_TLV_CHALLENGE_REPLY = 19, BABEL_TLV_CHALLENGE_REPLY = 19,
BABEL_TLV_MAX BABEL_TLV_MAX
}; };

22
proto/babel/config.Y
View file

@ -103,26 +103,24 @@ babel_iface_finish:
{ {
struct password_item *pass; struct password_item *pass;
uint len = 0, i = 0; uint len = 0, i = 0;
WALK_LIST(pass, *BABEL_IFACE->passwords) WALK_LIST(pass, *BABEL_IFACE->passwords)
{ {
/* Set default crypto algorithm (HMAC-SHA256) */ /* Set default crypto algorithm (HMAC-SHA256) */
if (!pass->alg) if (!pass->alg)
pass->alg = ALG_HMAC_SHA256; pass->alg = ALG_HMAC_SHA256;
if (pass->alg & ALG_HMAC) { if (!((pass->alg & ALG_HMAC) ||
if (pass->length < mac_type_length(pass->alg) || (pass->alg == ALG_BLAKE2S_128) ||
pass->length > mac_type_block_size(pass->alg)) (pass->alg == ALG_BLAKE2S_256) ||
cf_error("key length %d is not between output size %d and block size %d for algorithm %s", (pass->alg == ALG_BLAKE2B_256) ||
pass->length, mac_type_length(pass->alg), (pass->alg == ALG_BLAKE2B_512)))
mac_type_block_size(pass->alg), mac_type_name(pass->alg)); cf_error("Only HMAC and Blake2 algorithms are supported");
} 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");
}
len += mac_type_length(pass->alg); len += mac_type_length(pass->alg);
i++; i++;
} }
BABEL_IFACE->mac_num_keys = i; BABEL_IFACE->mac_num_keys = i;
BABEL_IFACE->mac_total_len = len; 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 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"); } | 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 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; } | AUTHENTICATION MAC PERMISSIVE { BABEL_IFACE->auth_type = BABEL_AUTH_MAC; BABEL_IFACE->auth_permissive = 1; }
| password_list { } | password_list
; ;
babel_iface_opts: babel_iface_opts:

255
proto/babel/packets.c
View file

@ -13,6 +13,7 @@
#include "babel.h" #include "babel.h"
#include "lib/mac.h" #include "lib/mac.h"
struct babel_pkt_header { struct babel_pkt_header {
u8 magic; u8 magic;
u8 version; u8 version;
@ -112,6 +113,12 @@ struct babel_subtlv_source_prefix {
u8 addr[0]; u8 addr[0];
} PACKED; } PACKED;
struct babel_tlv_mac {
u8 type;
u8 length;
u8 mac[0];
} PACKED;
struct babel_tlv_pc { struct babel_tlv_pc {
u8 type; u8 type;
u8 length; u8 length;
@ -119,19 +126,13 @@ struct babel_tlv_pc {
u8 index[0]; u8 index[0];
} PACKED; } PACKED;
struct babel_tlv_mac {
u8 type;
u8 length;
u8 mac[0];
} PACKED;
struct babel_tlv_challenge { struct babel_tlv_challenge {
u8 type; u8 type;
u8 length; u8 length;
u8 nonce[0]; u8 nonce[0];
} PACKED; } PACKED;
struct babel_mac_pseudohdr { struct babel_mac_pseudoheader {
u8 src_addr[16]; u8 src_addr[16];
u16 src_port; u16 src_port;
u8 dst_addr[16]; u8 dst_addr[16];
@ -234,7 +235,7 @@ struct babel_write_state {
if ((loop_pos > end) || (loop_pos + tlv->length > end)) \ if ((loop_pos > end) || (loop_pos + tlv->length > end)) \
{ \ { \
LOG_PKT("Bad TLV from %I via %s type %d pos %d - framing error", \ 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; \ frame_err = 1; \
break; \ break; \
} }
@ -306,11 +307,13 @@ put_ip6_ll(void *p, ip6_addr addr)
put_u32(p+4, _I3(addr)); put_u32(p+4, _I3(addr));
} }
/* /*
* Authentication-related functions * Authentication-related functions
*/ */
uint babel_auth_write_challenge(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len); 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_sign(struct babel_iface *ifa, ip_addr dest);
int babel_auth_check(struct babel_iface *ifa, int babel_auth_check(struct babel_iface *ifa,
ip_addr saddr, u16 sport, 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_write_seqno_request,
babel_handle_seqno_request babel_handle_seqno_request
}, },
[BABEL_TLV_CHALLENGE_REQ] = { [BABEL_TLV_CHALLENGE_REQUEST] = {
sizeof(struct babel_tlv), sizeof(struct babel_tlv_challenge),
NULL, NULL,
babel_auth_write_challenge, babel_auth_write_challenge,
NULL
}, },
[BABEL_TLV_CHALLENGE_REPLY] = { [BABEL_TLV_CHALLENGE_REPLY] = {
sizeof(struct babel_tlv), sizeof(struct babel_tlv_challenge),
NULL, NULL,
babel_auth_write_challenge, 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) static const struct babel_tlv_data *get_packet_subtlv_data(u8 type)
{ {
switch(type) switch (type)
{ {
case BABEL_SUBTLV_SOURCE_PREFIX: case BABEL_SUBTLV_SOURCE_PREFIX:
return &source_prefix_tlv_data; 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) if (tlv->plen == 0)
return PARSE_ERROR; return PARSE_ERROR;
switch(msg->type) switch (msg->type)
{ {
case BABEL_TLV_UPDATE: case BABEL_TLV_UPDATE:
/* Wildcard updates with source prefix MUST be silently ignored */ /* 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); return tlv_data[msg->type].write_tlv(hdr, msg, state, max_len);
} }
/* /*
* Packet RX/TX functions * Packet RX/TX functions
*/ */
@ -1343,7 +1349,7 @@ babel_write_queue(struct babel_iface *ifa, list *queue)
sl_free(p->msg_slab, msg); 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; uint plen = pos - (byte *) pkt;
put_u16(&pkt->length, plen - sizeof(struct babel_pkt_header)); 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 * 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 * @pkt: Pointer to the packet data
* @len: Length of received packet * @len: Length of received packet
* @saddr: Address of packet sender * @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", TRACE(D_PACKETS, "Packet received from %I via %s",
saddr, ifa->iface->name); 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; return;
init_list(&msgs); init_list(&msgs);
@ -1506,7 +1512,7 @@ babel_process_packet(struct babel_iface *ifa,
else /* PARSE_ERROR */ else /* PARSE_ERROR */
{ {
LOG_PKT("Bad TLV from %I via %s type %d pos %d - 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); sl_free(p->msg_slab, msg);
break; break;
} }
@ -1638,15 +1644,21 @@ babel_read_pc(struct babel_tlv *hdr, union babel_msg *m UNUSED,
{ {
struct babel_tlv_pc *tlv = (void *) hdr; struct babel_tlv_pc *tlv = (void *) hdr;
if (!state->auth.pc_seen) /* RFC 8967 4.3 (3) - If multiple PCs are found, only the first one is used */
{ 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;
}
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 = { 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; struct babel_tlv_challenge *tlv = (void *) hdr;
if (!state->is_unicast) 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; return PARSE_IGNORE;
state->auth.challenge_len = tlv->length; uint nonce_len = TLV_OPT_LENGTH(tlv);
if (state->auth.challenge_len) if (nonce_len > BABEL_AUTH_MAX_NONCE_LEN)
memcpy(state->auth.challenge, tlv->nonce, state->auth.challenge_len); return PARSE_IGNORE;
state->auth.challenge_len = nonce_len;
bmemcpy(state->auth.challenge, tlv->nonce, nonce_len);
state->auth.challenge_seen = 1; 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 = { 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; 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;
uint nonce_len = TLV_OPT_LENGTH(tlv);
if (nonce_len != BABEL_AUTH_NONCE_LEN)
return PARSE_IGNORE; return PARSE_IGNORE;
state->auth.challenge_reply_seen = 1;
memcpy(state->auth.challenge_reply, tlv->nonce, BABEL_AUTH_NONCE_LEN); 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_IGNORE; return PARSE_SUCCESS;
} }
static const struct babel_tlv_data challenge_reply_tlv_data = { 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 * static const struct babel_tlv_data *
get_auth_tlv_data(u8 type) get_auth_tlv_data(u8 type)
{ {
switch(type) switch (type)
{ {
case BABEL_TLV_PC: case BABEL_TLV_PC:
return &pc_tlv_data; return &pc_tlv_data;
case BABEL_TLV_CHALLENGE_REQ: case BABEL_TLV_CHALLENGE_REQUEST:
return &challenge_req_tlv_data; return &challenge_req_tlv_data;
case BABEL_TLV_CHALLENGE_REPLY: case BABEL_TLV_CHALLENGE_REPLY:
return &challenge_reply_tlv_data; return &challenge_reply_tlv_data;
@ -1720,7 +1735,7 @@ get_auth_tlv_data(u8 type)
uint uint
babel_auth_write_challenge(struct babel_tlv *hdr, union babel_msg *m, 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_tlv_challenge *tlv = (void *) hdr;
struct babel_msg_challenge *msg = &m->challenge; 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; return 0;
TLV_HDR(tlv, msg->type, len); TLV_HDR(tlv, msg->type, len);
memcpy(tlv->nonce, msg->nonce, msg->nonce_len); bmemcpy(tlv->nonce, msg->nonce, msg->nonce_len);
return len; return len;
} }
static int static void
babel_mac_hash(struct password_item *pass, babel_mac_fill(struct password_item *pass,
struct babel_mac_pseudohdr *phdr, struct babel_mac_pseudoheader *phdr,
byte *pkt, uint pkt_len, byte *pkt, uint pkt_len,
byte *buf, uint *buf_len) byte *mac)
{ {
struct mac_context ctx; struct mac_context ctx;
if (mac_type_length(pass->alg) > *buf_len)
return 1;
mac_init(&ctx, pass->alg, pass->password, pass->length); mac_init(&ctx, pass->alg, pass->password, pass->length);
mac_update(&ctx, (byte *)phdr, sizeof(*phdr)); mac_update(&ctx, (byte *)phdr, sizeof(*phdr));
mac_update(&ctx, (byte *)pkt, pkt_len); mac_update(&ctx, (byte *)pkt, pkt_len);
memcpy(mac, mac_final(&ctx), mac_get_length(&ctx));
*buf_len = mac_get_length(&ctx);
memcpy(buf, mac_final(&ctx), *buf_len);
mac_cleanup(&ctx); mac_cleanup(&ctx);
return 0;
} }
static void 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 saddr, u16 sport,
ip_addr daddr, u16 dport) 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 saddr, u16 sport,
ip_addr daddr, u16 dport) ip_addr daddr, u16 dport)
{ {
uint hash_len = (uint)(trailer - pkt);
struct babel_proto *p = ifa->proto; struct babel_proto *p = ifa->proto;
uint pkt_len = (uint)(trailer - pkt);
byte *end = trailer + trailer_len; byte *end = trailer + trailer_len;
btime now_ = current_real_time(); 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); saddr, ifa->ifname);
return 1; return 0;
} }
struct babel_mac_pseudoheader phdr;
babel_mac_build_phdr(&phdr, saddr, sport, daddr, dport); babel_mac_build_phdr(&phdr, saddr, sport, daddr, dport);
struct password_item *pass;
WALK_LIST(pass, *ifa->cf->passwords) WALK_LIST(pass, *ifa->cf->passwords)
{ {
byte mac_res[MAX_HASH_SIZE]; byte mac[MAX_HASH_SIZE];
uint mac_len = MAX_HASH_SIZE; uint mac_len = mac_type_length(pass->alg);
u8 frame_err = 0; uint frame_err = 0;
if (pass->accfrom > now_ || pass->accto < now_) if (pass->accfrom > now_ || pass->accto < now_)
continue; continue;
if (babel_mac_hash(pass, &phdr, babel_mac_fill(pass, &phdr, pkt, pkt_len, mac);
pkt, hash_len,
mac_res, &mac_len))
continue;
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) if (tlv->type != BABEL_TLV_MAC)
continue; continue;
if (tlv->length == mac_len && !memcmp(mac->mac, mac_res, mac_len)) if ((TLV_OPT_LENGTH(tlv) == mac_len) && !memcmp(tlv->mac, mac, mac_len))
return 0; return 1;
DBG("MAC mismatch key id %d pos %d len %d/%d\n", 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; WALK_TLVS_END;
if (frame_err) { if (frame_err)
DBG("MAC trailer TLV framing error\n"); return 0;
return 1;
}
} }
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); saddr, ifa->ifname);
return 1; return 0;
} }
/** /**
@ -1859,7 +1861,7 @@ babel_auth_check(struct babel_iface *ifa,
struct babel_pkt_header *pkt, struct babel_pkt_header *pkt,
byte *trailer, uint trailer_len) byte *trailer, uint trailer_len)
{ {
u8 frame_err UNUSED = 0; uint frame_err UNUSED = 0;
struct babel_proto *p = ifa->proto; struct babel_proto *p = ifa->proto;
struct babel_tlv *tlv; struct babel_tlv *tlv;
@ -1875,18 +1877,18 @@ babel_auth_check(struct babel_iface *ifa,
}; };
if (ifa->cf->auth_type == BABEL_AUTH_NONE) if (ifa->cf->auth_type == BABEL_AUTH_NONE)
return 0; return 1;
TRACE(D_PACKETS, "Checking packet authentication signature"); 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, trailer, trailer_len,
saddr, sport, saddr, sport,
daddr, dport)) daddr, dport))
goto fail; goto fail;
/* MAC verified; parse packet to check packet counter and challenge */ /* 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; union babel_msg msg;
enum parse_result res; enum parse_result res;
@ -1894,26 +1896,26 @@ babel_auth_check(struct babel_iface *ifa,
res = babel_read_tlv(tlv, &msg, &state); res = babel_read_tlv(tlv, &msg, &state);
if (res == PARSE_ERROR) if (res == PARSE_ERROR)
{ {
LOG_PKT_AUTH("Bad TLV from %I via %s type %d pos %d - 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->ifname, tlv->type, (int) ((byte *)tlv - (byte *)pkt));
goto fail; goto fail;
} }
} }
WALK_TLVS_END; WALK_TLVS_END;
if (babel_auth_check_pc(ifa, &state.auth)) if (!babel_auth_check_pc(ifa, &state.auth))
goto fail; goto fail;
TRACE(D_PACKETS, "Packet from %I via %s authenticated successfully", TRACE(D_PACKETS, "Packet from %I via %s authenticated successfully",
saddr, ifa->ifname); saddr, ifa->ifname);
return 0; return 1;
fail: 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, saddr, ifa->ifname,
ifa->cf->auth_permissive ? " but accepted in permissive mode" : ""); 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. * counter TLV that must be included in every packet.
*/ */
int 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_proto *p = ifa->proto;
struct babel_tlv_pc *msg; struct babel_tlv_pc *tlv;
int len; uint len;
if (ifa->cf->auth_type == BABEL_AUTH_NONE) if (ifa->cf->auth_type == BABEL_AUTH_NONE)
return 0; return 0;
msg = (void *)tlv; tlv = (void *) hdr;
len = sizeof(*msg) + BABEL_AUTH_INDEX_LEN; len = sizeof(struct babel_tlv_pc) + BABEL_AUTH_INDEX_LEN;
max_len += ifa->auth_tx_overhead; max_len += ifa->auth_tx_overhead;
if (len > max_len) 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; return 0;
} }
msg->type = BABEL_TLV_PC; TLV_HDR(tlv, BABEL_TLV_PC, len);
msg->length = len - sizeof(struct babel_tlv); put_u32(&tlv->pc, ifa->auth_pc++);
put_u32(&msg->pc, ifa->auth_pc++); memcpy(tlv->index, ifa->auth_index, BABEL_AUTH_INDEX_LEN);
memcpy(msg->index, ifa->auth_index, BABEL_AUTH_INDEX_LEN);
/* Reset index on overflow to 0 */ /* Reset index on overflow to 0 */
if (!ifa->auth_pc) if (!ifa->auth_pc)
@ -1971,58 +1972,48 @@ int
babel_auth_sign(struct babel_iface *ifa, ip_addr dest) babel_auth_sign(struct babel_iface *ifa, ip_addr dest)
{ {
struct babel_proto *p = ifa->proto; 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; sock *sk = ifa->sk;
byte *pos, *end;
btime now_;
int len;
if (ifa->cf->auth_type == BABEL_AUTH_NONE) if (ifa->cf->auth_type == BABEL_AUTH_NONE)
return 0; return 0;
hdr = (void *) sk->tbuf; struct babel_pkt_header *hdr = (void *) sk->tbuf;
len = get_u16(&hdr->length) + sizeof(struct babel_pkt_header); int len = get_u16(&hdr->length) + sizeof(struct babel_pkt_header);
pos = (byte *)hdr + len; byte *pkt = (byte *) hdr;
end = (byte *)hdr + ifa->tx_length + ifa->auth_tx_overhead; byte *pos = pkt + len;
tlv = (void *)pos; byte *end = pkt + ifa->tx_length + ifa->auth_tx_overhead;
now_ = current_real_time(); 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) WALK_LIST(pass, *ifa->cf->passwords)
{ {
struct babel_tlv_mac *msg = (void *)tlv; struct babel_tlv_mac *tlv = (void *) pos;
uint buf_len = (uint) (end - (byte *)msg - sizeof(*msg)); uint tlv_len = sizeof(struct babel_tlv_mac) + mac_type_length(pass->alg);
if (pass->genfrom > now_ || pass->gento < now_) if (pass->genfrom > now_ || pass->gento < now_)
continue; continue;
if (babel_mac_hash(pass, &phdr, if (pos + tlv_len > end)
(byte *)hdr, len,
msg->mac, &buf_len))
{ {
LOG_WARN("Insufficient space for MAC signatures on iface %s dest %I", LOG_WARN("Insufficient space for MAC signatures on iface %s dst %I (%d/%d)",
ifa->ifname, dest); ifa->ifname, dest, tlv_len, (int) (end-pos));
break; break;
} }
msg->type = BABEL_TLV_MAC; TLV_HDR(tlv, BABEL_TLV_MAC, tlv_len);
msg->length = buf_len; babel_mac_fill(pass, &phdr, pkt, len, tlv->mac);
tlv = NEXT_TLV(tlv); pos += tlv_len;
tot_len += buf_len + sizeof(*msg);
i++;
} }
DBG("Added %d MAC signatures (%d bytes) on ifa %s for dest %I\n", DBG("Added MAC signatures (%d bytes) on ifa %s for dest %I\n",
i, tot_len, ifa->ifname, dest); 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; 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 + sizeof(struct babel_tlv_mac) * ifa->cf->mac_num_keys +
ifa->cf->mac_total_len); ifa->cf->mac_total_len);
ifa->tx_length -= ifa->auth_tx_overhead; ifa->tx_length -= ifa->auth_tx_overhead;