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Lazy parsing

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This commit is contained in:
ruti 2024-11-16 20:59:25 +03:00
parent 64ffb2f64d
commit 0a9973a145
2 changed files with 96 additions and 76 deletions
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168
desync.c
View File

@ -121,9 +121,34 @@ static void wait_send(int sfd)
#define wait_send_if_support(sfd) // :(
#endif
static struct packet get_tcp_fake(const char *buffer, size_t n,
struct proto_info *info, const struct desync_params *opt)
{
struct packet pkt;
if (opt->fake_data.data) {
pkt = opt->fake_data;
}
else {
if (!info->type) {
if (is_tls_chello(buffer, n)) info->type = IS_HTTPS;
else if (is_http(buffer, n)) info->type = IS_HTTP;
}
pkt = info->type == IS_HTTP ? fake_http : fake_tls;
}
if (opt->fake_offset) {
if (pkt.size > opt->fake_offset) {
pkt.size -= opt->fake_offset;
pkt.data += opt->fake_offset;
}
else pkt.size = 0;
}
return pkt;
}
#ifdef __linux__
static ssize_t send_fake(int sfd, const char *buffer,
int cnt, long pos, struct desync_params *opt)
long pos, const struct desync_params *opt, struct packet pkt)
{
struct sockaddr_in6 addr = {};
socklen_t addr_size = sizeof(addr);
@ -134,20 +159,6 @@ static ssize_t send_fake(int sfd, const char *buffer,
return -1;
}
}
struct packet pkt;
if (opt->fake_data.data) {
pkt = opt->fake_data;
}
else {
pkt = cnt != IS_HTTP ? fake_tls : fake_http;
}
if (opt->fake_offset) {
if (pkt.size > opt->fake_offset) {
pkt.size -= opt->fake_offset;
pkt.data += opt->fake_offset;
}
else pkt.size = 0;
}
int fds[2];
if (pipe(fds) < 0) {
uniperror("pipe");
@ -235,23 +246,8 @@ static ssize_t send_fake(int sfd, const char *buffer,
OVERLAPPED ov = {};
static ssize_t send_fake(int sfd, const char *buffer,
int cnt, long pos, struct desync_params *opt)
long pos, const struct desync_params *opt, struct packet pkt)
{
struct packet pkt;
if (opt->fake_data.data) {
pkt = opt->fake_data;
}
else {
pkt = cnt != IS_HTTP ? fake_tls : fake_http;
}
if (opt->fake_offset) {
if (pkt.size > opt->fake_offset) {
pkt.size -= opt->fake_offset;
pkt.data += opt->fake_offset;
}
else pkt.size = 0;
}
char path[MAX_PATH], temp[MAX_PATH + 1];
int ps = GetTempPath(sizeof(temp), temp);
if (!ps) {
@ -397,21 +393,42 @@ static ssize_t send_late_oob(int sfd, char *buffer,
}
static void init_proto_info(
const char *buffer, size_t n, struct proto_info *info)
{
if (!info->init) {
char *host = 0;
if ((info->host_len = parse_tls(buffer, n, &host))) {
info->type = IS_HTTPS;
}
else if ((info->host_len = parse_http(buffer, n, &host, 0))) {
info->type = IS_HTTP;
}
info->host_pos = host ? host - buffer : 0;
info->init = 1;
}
}
static long gen_offset(long pos, int flag,
ssize_t n, long lp, int type, int hp, int len)
const char *buffer, size_t n, long lp, struct proto_info *info)
{
if (flag & (OFFSET_SNI | OFFSET_HOST)) {
if (!hp || ((flag & OFFSET_SNI) && type != IS_HTTPS)) {
init_proto_info(buffer, n, info);
if (!info->host_pos
|| ((flag & OFFSET_SNI) && info->type != IS_HTTPS)) {
return -1;
}
pos += hp;
pos += info->host_pos;
if (flag & OFFSET_END)
pos += len;
pos += info->host_len;
else if (flag & OFFSET_MID)
pos += (len / 2);
pos += (info->host_len / 2);
else if (flag & OFFSET_RAND)
pos += (rand() % len);
pos += (rand() % info->host_len);
}
else if (flag & OFFSET_RAND) {
pos += lp + (rand() % (n - lp));
@ -426,54 +443,33 @@ static long gen_offset(long pos, int flag,
}
ssize_t desync(int sfd, char *buffer, size_t bfsize,
ssize_t n, ssize_t offset, const struct sockaddr *dst, int dp_c)
static ssize_t tamp(char *buffer, size_t bfsize, ssize_t n,
const struct desync_params *dp, struct proto_info *info)
{
struct desync_params dp = params.dp[dp_c];
char *host = 0;
int len = 0, type = 0, host_pos = 0;
if (offset == 0) {
if ((len = parse_tls(buffer, n, &host))) {
type = IS_HTTPS;
}
else if ((len = parse_http(buffer, n, &host, 0))) {
type = IS_HTTP;
}
if (len && host) {
LOG(LOG_S, "host: %.*s (%zd)\n",
len, host, host - buffer);
host_pos = host - buffer;
}
else {
INIT_HEX_STR(buffer, (n > 16 ? 16 : n));
LOG(LOG_S, "bytes: %s (%zd)\n", HEX_STR, n);
}
}
// modify packet
if (type == IS_HTTP && dp.mod_http) {
if (dp->mod_http && is_http(buffer, n)) {
LOG(LOG_S, "modify HTTP: n=%zd\n", n);
if (mod_http(buffer, n, dp.mod_http)) {
if (mod_http(buffer, n, dp->mod_http)) {
LOG(LOG_E, "mod http error\n");
return -1;
}
}
else if (type == IS_HTTPS && dp.tlsrec_n) {
else if (dp->tlsrec_n && is_tls_chello(buffer, n)) {
long lp = 0;
struct part part;
int i = 0, r = 0, rc = 0;
for (; r > 0 || i < dp.tlsrec_n; rc++, r--) {
for (; r > 0 || i < dp->tlsrec_n; rc++, r--) {
if (r <= 0) {
part = dp.tlsrec[i];
part = dp->tlsrec[i];
r = part.r; i++;
}
long pos = rc * 5;
pos += gen_offset(part.pos,
part.flag, n - pos - 5, lp, type, host_pos - 5, len);
pos += (long)part.s * (part.r - r);
part.flag, buffer, n - pos, lp, info);
if (part.pos != pos) {
pos -= 5;
}
pos += (long )part.s * (part.r - r);
if (pos < lp) {
LOG(LOG_E, "tlsrec cancel: %ld < %ld\n", pos, lp);
break;
@ -488,6 +484,28 @@ ssize_t desync(int sfd, char *buffer, size_t bfsize,
lp = pos + 5;
}
}
return n;
}
ssize_t desync(int sfd, char *buffer, size_t bfsize,
ssize_t n, ssize_t offset, const struct sockaddr *dst, int dp_c)
{
struct desync_params dp = params.dp[dp_c];
struct proto_info info = { 0 };
if (offset == 0 && params.debug) {
init_proto_info(buffer, n, &info);
if (info.host_pos) {
LOG(LOG_S, "host: %.*s (%d)\n",
info.host_len, buffer + info.host_pos, info.host_pos);
} else {
INIT_HEX_STR(buffer, (n > 16 ? 16 : n));
LOG(LOG_S, "bytes: %s (%zd)\n", HEX_STR, n);
}
}
n = tamp(buffer, bfsize, n, &dp, &info);
#ifdef __linux__
if (!offset && dp.drop_sack && drop_sack(sfd)) {
return -1;
@ -502,10 +520,8 @@ ssize_t desync(int sfd, char *buffer, size_t bfsize,
part = dp.parts[i];
r = part.r; i++;
}
long pos = gen_offset(part.pos,
part.flag, n, lp, type, host_pos, len);
pos += (long)part.s * (part.r - r);
long pos = gen_offset(part.pos, part.flag, buffer, n, lp, &info);
pos += (long )part.s * (part.r - r);
if (!(part.flag & OFFSET_START) && offset && pos <= offset) {
LOG(LOG_S, "offset: %zd, skip\n", offset);
@ -521,7 +537,7 @@ ssize_t desync(int sfd, char *buffer, size_t bfsize,
#ifdef FAKE_SUPPORT
case DESYNC_FAKE:
if (pos != lp) s = send_fake(sfd,
buffer + lp, type, pos - lp, &dp);
buffer + lp, pos - lp, &dp, get_tcp_fake(buffer, n, &info, &dp));
break;
#endif
case DESYNC_DISORDER:

4
desync.h
View File

@ -18,4 +18,8 @@ int setttl(int fd, int ttl);
int post_desync(int sfd, int dp_c);
struct proto_info {
char init, type;
int host_len, host_pos;
};
#endif