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nfqws: synack desync mode

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bol-van
2021-04-07 12:13:46 +03:00
parent 8229bcc98b
commit fe8cada8ae
14 changed files with 99 additions and 23 deletions
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53
nfq/desync.c
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@@ -60,6 +60,10 @@ void desync_init()
}
bool desync_valid_zero_stage(enum dpi_desync_mode mode)
{
return mode==DESYNC_SYNACK;
}
bool desync_valid_first_stage(enum dpi_desync_mode mode)
{
return mode==DESYNC_FAKE || mode==DESYNC_RST || mode==DESYNC_RSTACK;
@@ -78,6 +82,8 @@ enum dpi_desync_mode desync_mode_from_string(const char *s)
return DESYNC_RST;
else if (!strcmp(s,"rstack"))
return DESYNC_RSTACK;
else if (!strcmp(s,"synack"))
return DESYNC_SYNACK;
else if (!strcmp(s,"disorder"))
return DESYNC_DISORDER;
else if (!strcmp(s,"disorder2"))
@@ -126,6 +132,12 @@ packet_process_result dpi_desync_packet(uint8_t *data_pkt, size_t len_pkt, struc
t_ctrack *ctrack=NULL;
bool bReverse=false;
struct sockaddr_storage src, dst;
uint8_t newdata[DPI_DESYNC_MAX_FAKE_LEN+100];
size_t newlen;
uint8_t ttl_orig,ttl_fake,flags_orig,scale_factor;
uint32_t *timestamps;
if (!!ip == !!ip6hdr) return res; // one and only one must be present
if (CONNTRACK_REQUIRED)
@@ -139,17 +151,44 @@ packet_process_result dpi_desync_packet(uint8_t *data_pkt, size_t len_pkt, struc
tcp_rewrite_winsize(tcphdr, params.wsize, params.wscale);
res=modify;
}
if (params.wssize && !bReverse && (ctrack && !ctrack->b_wssize_cutoff))
if (bReverse) return res; // nothing to do. do not waste cpu
if (params.wssize && (ctrack && !ctrack->b_wssize_cutoff))
{
tcp_rewrite_winsize(tcphdr, params.wssize, params.wsscale);
res=modify;
}
if (bReverse || !params.wssize && params.desync_mode==DESYNC_NONE && !params.hostcase && !params.hostnospace && !params.domcase) return res; // nothing to do. do not waste cpu
if (params.desync_mode0!=DESYNC_NONE || params.desync_mode!=DESYNC_NONE) // save some cpu
{
ttl_orig = ip ? ip->ip_ttl : ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_hlim;
ttl_fake = params.desync_ttl ? params.desync_ttl : ttl_orig;
flags_orig = *((uint8_t*)tcphdr+13);
scale_factor = tcp_find_scale_factor(tcphdr);
timestamps = tcp_find_timestamps(tcphdr);
extract_endpoints(ip, ip6hdr, tcphdr, &src, &dst);
}
if (params.desync_mode0==DESYNC_SYNACK && tcp_syn_segment(tcphdr))
{
newlen = sizeof(newdata);
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, TH_SYN|TH_ACK, tcphdr->th_seq, tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
ttl_fake,params.desync_tcp_fooling_mode,
NULL, 0, newdata, &newlen))
{
return res;
}
DLOG("sending fake SYNACK\n");
if (!rawsend_rep((struct sockaddr *)&dst, params.desync_fwmark, newdata, newlen))
return res;
}
if (!params.wssize && params.desync_mode==DESYNC_NONE && !params.hostcase && !params.hostnospace && !params.domcase) return res; // nothing to do. do not waste cpu
if (!(tcphdr->th_flags & TH_SYN) && len_payload)
{
struct sockaddr_storage src, dst;
const uint8_t *fake;
size_t fake_size;
char host[256];
@@ -251,7 +290,6 @@ packet_process_result dpi_desync_packet(uint8_t *data_pkt, size_t len_pkt, struc
return res;
}
extract_endpoints(ip, ip6hdr, tcphdr, &src, &dst);
if (params.debug)
{
printf("dpi desync src=");
@@ -261,14 +299,7 @@ packet_process_result dpi_desync_packet(uint8_t *data_pkt, size_t len_pkt, struc
printf("\n");
}
uint8_t newdata[DPI_DESYNC_MAX_FAKE_LEN+100];
size_t newlen;
uint8_t ttl_orig = ip ? ip->ip_ttl : ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_hlim;
uint8_t ttl_fake = params.desync_ttl ? params.desync_ttl : ttl_orig;
uint8_t flags_orig = *((uint8_t*)tcphdr+13);
uint32_t *timestamps = tcp_find_timestamps(tcphdr);
enum dpi_desync_mode desync_mode = params.desync_mode;
uint8_t scale_factor = tcp_find_scale_factor(tcphdr);
bool b;
newlen = sizeof(newdata);