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stun: misc fixes
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@pkova
pkova committed Nov 30, 2023
1 parent 2a3ca0e commit f9151a9
Showing 1 changed file with 42 additions and 78 deletions.
120 changes: 42 additions & 78 deletions pkg/vere/io/ames.c
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,8 @@

#include "zlib.h"

#include <ent.h>

#define FINE_PAGE 4096 // packets per page
#define FINE_FRAG 1024 // bytes per fragment packet
#define FINE_PATH_MAX 384 // longest allowed scry path
Expand Down Expand Up @@ -1316,9 +1318,9 @@ _stun_send_response_cb(uv_udp_send_t *rep_u, c3_i sas_i)
u3_stun_send* snd_u = (u3_stun_send*)rep_u;
if ( sas_i != 0 ) {
u3l_log("stun: _stun_send_response_cb fail_sync: %s", uv_strerror(sas_i));
c3_free(snd_u->hun_y);
c3_free(snd_u);
}
c3_free(snd_u->hun_y);
c3_free(snd_u);
}

static void _stun_on_request(u3_ames *sam_u, c3_y* buf_r,
Expand Down Expand Up @@ -1410,14 +1412,11 @@ _stun_on_response(u3_ames* sam_u, c3_y* buf_y, c3_w buf_len)
case STUN_KEEPALIVE: break; // ignore; duplicate response
case STUN_TRYING: {
sam_u->sun_u.sat_y = STUN_KEEPALIVE;
c3_y buf_y[12] = {0};
c3_i sas_i = uv_random(NULL, NULL, buf_y, 12, 0, NULL);
if (sas_i != 0) {
u3l_log("stun: can't STUN uv_random fail: %s", uv_strerror(sas_i));
if ( ent_getentropy(sam_u->sun_u.tid_y, 12) ) {
u3l_log("stun: getentropy fail: %s", strerror(errno));
_stun_on_lost(sam_u);
}
else {
memcpy(sam_u->sun_u.tid_y, buf_y, 12);
uv_timer_start(&sam_u->sun_u.tim_u, _stun_timer_cb, 25*1000, 0);
}
} break;
Expand Down Expand Up @@ -1599,15 +1598,10 @@ _stun_czar(u3_ames* sam_u, c3_d tim_d)
static void
_stun_start(u3_ames* sam_u, c3_o fail)
{
c3_y buf_y[12] = {0};
// XX uv_random may block indefinitely when not enough entropy is available.
c3_i sas_i = uv_random(NULL, NULL, buf_y, 12, 0, NULL);

if (sas_i != 0) {
u3l_log("stun: can't STUN uv_random fail: %s", uv_strerror(sas_i));
if ( ent_getentropy(sam_u->sun_u.tid_y, 12) ) {
u3l_log("stun: getentropy fail: %s", strerror(errno));
_stun_on_lost(sam_u);
} else {
memcpy(sam_u->sun_u.tid_y, buf_y, 12);
_stun_czar(sam_u, (fail == c3n) ? 500 : 39500);
}
}
Expand All @@ -1621,7 +1615,7 @@ _stun_resolve_dns_cb(uv_timer_t* tim_u)
c3_y imp_y = sam_u->sun_u.dad_y;
sam_u->sun_u.lan_u.por_s = _ames_czar_port(imp_y);

if (!sam_u->sun_u.dns_c) {
if ( !sam_u->sun_u.dns_c ) {
sam_u->sun_u.dns_c = _ames_czar_dns(imp_y, sam_u->dns_c);
}

Expand All @@ -1634,7 +1628,8 @@ _stun_resolve_dns_cb(uv_timer_t* tim_u)
hints.ai_family = AF_INET; // only IPv4 addresses

if (0 != (sas_i = uv_getaddrinfo(u3L, adr_u, _stun_czar_cb,
sam_u->sun_u.dns_c, 0, &hints))) {
sam_u->sun_u.dns_c, 0, &hints)))
{
u3l_log("stun: uv_getaddrinfo failed %s %s", uv_strerror(sas_i), sam_u->sun_u.dns_c);
_ames_czar_gone(sam_u, time(0), sam_u->sun_u.dad_y, sam_u->dns_c);
_stun_on_lost(sam_u);
Expand All @@ -1643,80 +1638,43 @@ _stun_resolve_dns_cb(uv_timer_t* tim_u)
}
}

static c3_w
_stun_find_attribute(c3_y* buf_y, c3_w len,
c3_y atr[2], c3_y atr_len[2],
c3_w min_len)
{
c3_w i, header, index, cur;

c3_o stop = c3n;
i = 0;
header = 20;
index = 0;
cur = 0;

while (len-- && stop == c3n) {
cur = header + i;
if (len < min_len) {
stop = c3y;
}
else if (buf_y[cur] == atr[0] && buf_y[cur + 1] == atr[1]&&
buf_y[cur + 2] == atr_len[0] && buf_y[cur + 3] == atr_len[1] ) {
stop = c3y;
index = cur;
}
else {
i = i + 1;
}
}
return index;
}

static c3_w
_stun_find_xor_mapped_address(c3_y* buf_y, c3_w buf_len)
{
c3_y xor_buf[2]; xor_buf[0]= 0x00; xor_buf[1]= 0x20;
c3_y atr_len[2]; atr_len[0]= 0x00; atr_len[1]= 0x08;
c3_y xor_y[4] = {0x00, 0x20, 0x00, 0x08};

if (buf_len < 40) { // At least STUN header, XOR-MAPPED-ADDRESS & FINGERPRINT
return 0;
}
else {
c3_w len = buf_len - 20 + 1;
c3_w index = _stun_find_attribute(buf_y, len, xor_buf, atr_len, 9);
c3_y* fin_y = memmem(buf_y + 20, buf_len - 20, xor_y, sizeof(xor_y));
// If non-zero, skip attribute type, length, reserved byte and IP family
return (index == 0) ? 0 : index + 6;
return (fin_y) ? 0 : fin_y + 6;
}
}

static c3_o
_stun_has_fingerprint(c3_y* buf_y, c3_w buf_len)
{
c3_y finger[4];
c3_y ned_y[4] = {0x80, 0x28, 0x00, 0x04};

c3_y finger_buf[2]; finger_buf[0]= 0x80; finger_buf[1]= 0x28;
c3_y atr_len[2]; atr_len[0]= 0x00; atr_len[1]= 0x04;

if (buf_len < 28) { // At least STUN header and FINGERPRINT
if ( buf_len < 28 ) { // At least STUN header and FINGERPRINT
return c3n;
}
else {
c3_w len = buf_len - 20 + 1;
c3_w index = _stun_find_attribute(buf_y, len, finger_buf, atr_len, 8);
if (index == 0) {

{
c3_y* fin_y = memmem(buf_y + 20, buf_len - 20, ned_y, sizeof(ned_y));

if ( !fin_y ) {
return c3n;
}
else {
index += 4; // Skip attribute type and length
finger[0] = buf_y[index]; finger[1] = buf_y[index + 1];
finger[2] = buf_y[index + 2]; finger[3] = buf_y[index + 3];

c3_w fingerprint = _ames_sift_word(finger);
c3_w fingerprint = _ames_sift_word(fin_y + sizeof(ned_y));
c3_w init = crc32(0L, Z_NULL, 0);
c3_w crc = htonl(crc32(init, buf_y, index - 4) ^ 0x5354554e);

return fingerprint == crc;
return fingerprint == crc ? c3y : c3n;
}
}
}
Expand Down Expand Up @@ -1750,12 +1708,15 @@ _stun_is_our_response(c3_y* buf_y, c3_y tid_y[12], c3_w buf_len)

// Expects at least:
// STUN header, 12 byte XOR-MAPPED-ADDRESS and 8 byte FINGERPRINT
return !(buf_len == 40 &&
buf_y[0] == 0x01 && buf_y[1] == 0x01 &&
memcmp(&cookie, buf_y + 4, 4) == 0 &&
memcmp(tid_y, buf_y + 8, 12) == 0 &&
_stun_has_fingerprint(buf_y, buf_len)
);
if ( (buf_len == 40) &&
(buf_y[0] == 0x01 && buf_y[1] == 0x01) &&
(memcmp(&cookie, buf_y + 4, 4) == 0) &&
(memcmp(tid_y, buf_y + 8, 12) == 0) &&
(c3y == _stun_has_fingerprint(buf_y, buf_len)) )
{
return c3y;
}
return c3n;
}

static c3_o
Expand All @@ -1765,12 +1726,14 @@ _stun_is_request(c3_y* buf_y, c3_w buf_len)

// Expects at least:
// STUN header and 8 byte FINGERPRINT
return !(buf_len >= 28 &&
buf_y[0] == 0x0 && buf_y[1] == 0x01 &&
memcmp(&cookie, buf_y + 4, 4) == 0 &&
_stun_has_fingerprint(buf_y, buf_len)
);

if ( (buf_len >= 28) &&
(buf_y[0] == 0x0 && buf_y[1] == 0x01) &&
(memcmp(&cookie, buf_y + 4, 4) == 0) &&
(c3y == _stun_has_fingerprint(buf_y, buf_len)) )
{
return c3y;
}
return c3n;
}

static c3_o
Expand Down Expand Up @@ -2804,7 +2767,8 @@ _ames_ef_turf(u3_ames* sam_u, u3_noun tuf)
}

// XX invalidate sam_u->imp_w &c ?
// also invalidate sun_u.dns_c
c3_free(sam_u->sun_u.dns_c);
sam_u->sun_u.dns_c = 0;

u3z(tuf);
}
Expand Down

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