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joel-sujoel-su
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Implement BEP-42: DHT Security extension
1 parent ee2b410 commit cd7aa69

1 file changed

Lines changed: 187 additions & 3 deletions

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‎dht.c‎

Lines changed: 187 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -293,6 +293,8 @@ struct parsed_message {
293293
unsigned char values6[PARSE_VALUES6_LEN];
294294
unsigned short values6_len;
295295
unsigned short want;
296+
unsigned char ip[18];
297+
unsigned short ip_len;
296298
};
297299

298300
static int parse_message(const unsigned char *buf, int buflen,
@@ -315,6 +317,9 @@ static int have_v = 0;
315317
static unsigned char my_v[9];
316318
static unsigned char secret[8];
317319
static unsigned char oldsecret[8];
320+
static unsigned char ext_ip[18];
321+
static unsigned char ext_ip_len = 0;
322+
static unsigned int ext_ip_votes = 0;
318323

319324
static struct bucket *buckets = NULL;
320325
static struct bucket *buckets6 = NULL;
@@ -341,6 +346,111 @@ static time_t expire_stuff_time;
341346
static time_t token_bucket_time;
342347
static int token_bucket_tokens;
343348

349+
static const uint32_t crc32c_table[256] = {
350+
0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
351+
0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
352+
0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
353+
0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
354+
0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
355+
0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
356+
0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
357+
0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
358+
0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
359+
0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
360+
0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
361+
0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
362+
0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
363+
0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
364+
0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
365+
0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
366+
0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
367+
0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
368+
0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
369+
0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
370+
0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
371+
0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
372+
0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
373+
0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
374+
0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
375+
0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
376+
0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
377+
0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
378+
0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
379+
0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
380+
0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
381+
0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
382+
0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
383+
0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
384+
0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
385+
0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
386+
0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
387+
0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
388+
0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
389+
0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
390+
0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
391+
0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
392+
0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
393+
0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
394+
0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
395+
0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
396+
0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
397+
0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
398+
0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
399+
0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
400+
0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
401+
0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
402+
0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
403+
0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
404+
0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
405+
0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
406+
0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
407+
0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
408+
0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
409+
0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
410+
0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
411+
0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
412+
0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
413+
0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
414+
};
415+
416+
static uint32_t
417+
crc32c(const unsigned char *data, size_t len)
418+
{
419+
uint32_t crc = 0xffffffff;
420+
421+
while (len--)
422+
crc = crc32c_table[(crc ^ *data++) & 0xff] ^ (crc >> 8);
423+
424+
return crc ^ 0xffffffff;
425+
}
426+
427+
static uint32_t
428+
compute_id_prefix(const unsigned char *id, const unsigned char *ip,
429+
size_t ip_len)
430+
{
431+
unsigned char buf[8];
432+
433+
if (ip_len == 6) {
434+
buf[0] = (ip[0] & 0x3) | (id[19] & 0x7) << 5;
435+
buf[1] = ip[1] & 0xf;
436+
buf[2] = ip[2] & 0x3f;
437+
buf[3] = ip[3] & 0xff;
438+
return crc32c(buf, 4);
439+
} else if (ip_len == 18) {
440+
buf[0] = (ip[0] & 0x1) | (id[19] & 0x7) << 5;
441+
buf[1] = ip[1] & 0x3;
442+
buf[2] = ip[2] & 0x7;
443+
buf[3] = ip[3] & 0xf;
444+
buf[4] = ip[4] & 0x1f;
445+
buf[5] = ip[5] & 0x3f;
446+
buf[6] = ip[6] & 0x7f;
447+
buf[7] = ip[7] & 0xff;
448+
return crc32c(buf, 8);
449+
}
450+
451+
return 0;
452+
}
453+
344454
FILE *dht_debug = NULL;
345455

346456
#ifdef __GNUC__
@@ -2077,6 +2187,26 @@ dht_periodic(const void *buf, size_t buflen,
20772187

20782188
switch(message) {
20792189
case REPLY:
2190+
if(m.ip_len == 6 || m.ip_len == 18) {
2191+
if (!ext_ip_votes) {
2192+
memcpy(ext_ip, m.ip, m.ip_len);
2193+
ext_ip_len = m.ip_len;
2194+
ext_ip_votes++;
2195+
} else if (ext_ip_len == m.ip_len &&
2196+
!memcmp(ext_ip, m.ip, m.ip_len)) {
2197+
if (ext_ip_votes == 10) {
2198+
uint32_t prefix = compute_id_prefix(myid, ext_ip,
2199+
ext_ip_len);
2200+
myid[0] = prefix >> 24;
2201+
myid[1] = (prefix >> 16) & 0xff;
2202+
myid[2] = ((prefix >> 8) & 0xf8) | (myid[2] & 0x7);
2203+
2204+
ext_ip_votes = 0;
2205+
} else
2206+
ext_ip_votes++;
2207+
} else
2208+
ext_ip_votes--;
2209+
}
20802210
if(m.tid_len != 4) {
20812211
debugf("Broken node truncates transaction ids: ");
20822212
debug_printable(buf, buflen);
@@ -2532,7 +2662,21 @@ send_pong(const struct sockaddr *sa, int salen,
25322662
{
25332663
char buf[512];
25342664
int i = 0, rc;
2535-
rc = snprintf(buf + i, 512 - i, "d1:rd2:id20:"); INC(i, rc, 512);
2665+
rc = snprintf(buf + i, 512 - i, "d2:ip"); INC(i, rc, 512);
2666+
if (sa->sa_family == AF_INET) {
2667+
struct sockaddr_in *sin = (struct sockaddr_in*)sa;
2668+
rc = snprintf(buf + i, 512 - i, "6:"); INC(i, rc, 512);
2669+
COPY(buf, i, &sin->sin_addr, 4, 512);
2670+
COPY(buf, i, &sin->sin_port, 2, 512);
2671+
} else if (sa->sa_family == AF_INET6) {
2672+
struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)sa;
2673+
rc = snprintf(buf + i, 512 - i, "18:"); INC(i, rc, 512);
2674+
COPY(buf, i, &sin6->sin6_addr, 16, 512);
2675+
COPY(buf, i, &sin6->sin6_port, 2, 512);
2676+
} else {
2677+
abort();
2678+
}
2679+
rc = snprintf(buf + i, 512 - i, "1:rd2:id20:"); INC(i, rc, 512);
25362680
COPY(buf, i, myid, 20, 512);
25372681
rc = snprintf(buf + i, 512 - i, "e1:t%d:", tid_len); INC(i, rc, 512);
25382682
COPY(buf, i, tid, tid_len, 512);
@@ -2585,7 +2729,21 @@ send_nodes_peers(const struct sockaddr *sa, int salen,
25852729
char buf[2048];
25862730
int i = 0, rc, j0, j, k, len;
25872731

2588-
rc = snprintf(buf + i, 2048 - i, "d1:rd2:id20:"); INC(i, rc, 2048);
2732+
rc = snprintf(buf + i, 2048 - i, "d2:ip"); INC(i, rc, 2048);
2733+
if (sa->sa_family == AF_INET) {
2734+
struct sockaddr_in *sin = (struct sockaddr_in*)sa;
2735+
rc = snprintf(buf + i, 2048 - i, "6:"); INC(i, rc, 2048);
2736+
COPY(buf, i, &sin->sin_addr, 4, 2048);
2737+
COPY(buf, i, &sin->sin_port, 2, 2048);
2738+
} else if (sa->sa_family == AF_INET6) {
2739+
struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)sa;
2740+
rc = snprintf(buf + i, 2048 - i, "18:"); INC(i, rc, 2048);
2741+
COPY(buf, i, &sin6->sin6_addr, 16, 2048);
2742+
COPY(buf, i, &sin6->sin6_port, 2, 2048);
2743+
} else {
2744+
abort();
2745+
}
2746+
rc = snprintf(buf + i, 2048 - i, "1:rd2:id20:"); INC(i, rc, 2048);
25892747
COPY(buf, i, myid, 20, 2048);
25902748
if(nodes_len > 0) {
25912749
rc = snprintf(buf + i, 2048 - i, "5:nodes%d:", nodes_len);
@@ -2815,7 +2973,21 @@ send_peer_announced(const struct sockaddr *sa, int salen,
28152973
char buf[512];
28162974
int i = 0, rc;
28172975

2818-
rc = snprintf(buf + i, 512 - i, "d1:rd2:id20:"); INC(i, rc, 512);
2976+
rc = snprintf(buf + i, 512 - i, "d2:ip"); INC(i, rc, 512);
2977+
if (sa->sa_family == AF_INET) {
2978+
struct sockaddr_in *sin = (struct sockaddr_in*)sa;
2979+
rc = snprintf(buf + i, 512 - i, "6:"); INC(i, rc, 512);
2980+
COPY(buf, i, &sin->sin_addr, 4, 512);
2981+
COPY(buf, i, &sin->sin_port, 2, 512);
2982+
} else if (sa->sa_family == AF_INET6) {
2983+
struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)sa;
2984+
rc = snprintf(buf + i, 512 - i, "18:"); INC(i, rc, 512);
2985+
COPY(buf, i, &sin6->sin6_addr, 16, 512);
2986+
COPY(buf, i, &sin6->sin6_port, 2, 512);
2987+
} else {
2988+
abort();
2989+
}
2990+
rc = snprintf(buf + i, 512 - i, "1:rd2:id20:"); INC(i, rc, 512);
28192991
COPY(buf, i, myid, 20, 512);
28202992
rc = snprintf(buf + i, 512 - i, "e1:t%d:", tid_len);
28212993
INC(i, rc, 512);
@@ -3042,6 +3214,18 @@ parse_message(const unsigned char *buf, int buflen,
30423214
debugf("eek... unexpected end for want.\n");
30433215
}
30443216

3217+
p = dht_memmem(buf, buflen, "2:ip", 4);
3218+
if(p) {
3219+
long l;
3220+
char *q;
3221+
l = strtol((char*)p + 4, &q, 10);
3222+
if(q && *q == ':' && l > 0 && l <= 18) {
3223+
CHECK(q + 1, l);
3224+
memcpy(m->ip, q + 1, l);
3225+
m->ip_len = l;
3226+
}
3227+
}
3228+
30453229
#undef CHECK
30463230

30473231
if(dht_memmem(buf, buflen, "1:y1:r", 6))

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