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GoodbyeDPI
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Update goodbyedpi.c

pull/319/head
SashaXser 2 years ago
committed by GitHub
parent
110ba354d8
commit
cda71e0c61
No known key found for this signature in database GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 117 additions and 135 deletions
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  1. 108
      src/goodbyedpi.c

108
src/goodbyedpi.c
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@ -393,29 +393,22 @@ static int find_header_and_get_info(const char *pktdata, unsigned int pktlen,
static int extract_sni(const char *pktdata, unsigned int pktlen,
char **hostnameaddr, unsigned int *hostnamelen) {
unsigned int ptr = 0;
unsigned const char *d = (unsigned const char *)pktdata;
unsigned const char *hnaddr = 0;
const unsigned char *d = (const unsigned char *)pktdata;
const unsigned char *hnaddr = NULL;
int hnlen = 0;
while (ptr + 8 < pktlen) {
/* Search for specific Extensions sequence */
if (d[ptr] == '\0' && d[ptr+1] == '\0' && d[ptr+2] == '\0' &&
d[ptr+4] == '\0' && d[ptr+6] == '\0' && d[ptr+7] == '\0' &&
/* Check Extension length, Server Name list length
* and Server Name length relations
*/
d[ptr+3] - d[ptr+5] == 2 && d[ptr+5] - d[ptr+8] == 3)
{
if (ptr + 8 + d[ptr+8] > pktlen) {
return FALSE;
}
hnaddr = &d[ptr+9];
hnlen = d[ptr+8];
/* Limit hostname size up to 253 bytes */
if (hnlen < 3 || hnlen > HOST_MAXLEN) {
if (ptr + 8 + hnlen > pktlen || hnlen < 3 || hnlen > HOST_MAXLEN) {
return FALSE;
}
/* Validate that hostname has only ascii lowercase characters */
for (int i = 0; i < hnlen; i++) {
if (!((hnaddr[i] >= '0' && hnaddr[i] <= '9') ||
(hnaddr[i] >= 'a' && hnaddr[i] <= 'z') ||
@ -424,15 +417,18 @@ static int extract_sni(const char *pktdata, unsigned int pktlen,
return FALSE;
}
}
*hostnameaddr = (char*)hnaddr;
*hostnamelen = (unsigned int)hnlen;
return TRUE;
}
ptr++;
}
return FALSE;
}
static inline void change_window_size(const PWINDIVERT_TCPHDR ppTcpHdr, unsigned int size) {
if (size >= 1 && size <= 0xFFFFu) {
ppTcpHdr->Window = htons((u_short)size);
@ -441,118 +437,107 @@ static inline void change_window_size(const PWINDIVERT_TCPHDR ppTcpHdr, unsigned
/* HTTP method end without trailing space */
static const char *find_http_method_end(const char *pkt, unsigned int http_frag, int *is_fragmented) {
const char *method_end = NULL;
int fragmented = 0;
switch (*pkt) {
case 'G':
if (strncmp(pkt, "GET", 3) == 0) {
if (is_fragmented)
*is_fragmented = 0;
return pkt + 3;
method_end = pkt + 3;
}
break;
case 'P':
if (strncmp(pkt, "POST", 4) == 0) {
if (is_fragmented)
*is_fragmented = 0;
return pkt + 4;
method_end = pkt + 4;
}
break;
case 'H':
if (strncmp(pkt, "HEAD", 4) == 0) {
if (is_fragmented)
*is_fragmented = 0;
return pkt + 4;
method_end = pkt + 4;
}
break;
case 'O':
if (strncmp(pkt, "OPTIONS", 7) == 0) {
if (is_fragmented)
*is_fragmented = 0;
return pkt + 7;
method_end = pkt + 7;
}
break;
case 'D':
if (strncmp(pkt, "DELETE", 6) == 0) {
if (is_fragmented)
*is_fragmented = 0;
return pkt + 6;
method_end = pkt + 6;
}
break;
case 'T':
if (strncmp(pkt, "TRACE", 5) == 0) {
if (is_fragmented)
*is_fragmented = 0;
return pkt + 5;
method_end = pkt + 5;
}
break;
case 'C':
if (strncmp(pkt, "CONNECT", 7) == 0) {
if (is_fragmented)
*is_fragmented = 0;
return pkt + 7;
method_end = pkt + 7;
}
break;
default:
/* Try to find HTTP method in a second part of fragmented packet */
if ((http_frag == 1 || http_frag == 2)) {
break;
}
if (method_end == NULL && (http_frag == 1 || http_frag == 2)) {
switch (*pkt) {
case 'E':
if (strncmp(pkt, "ET", http_frag) == 0) {
if (is_fragmented)
*is_fragmented = 1;
return pkt + http_frag - 1;
method_end = pkt + http_frag - 1;
fragmented = 1;
}
break;
case 'S':
if (strncmp(pkt, "ST", http_frag) == 0) {
if (is_fragmented)
*is_fragmented = 1;
return pkt + http_frag - 1;
method_end = pkt + http_frag - 1;
fragmented = 1;
}
break;
case 'A':
if (strncmp(pkt, "AD", http_frag) == 0) {
if (is_fragmented)
*is_fragmented = 1;
return pkt + http_frag - 1;
method_end = pkt + http_frag - 1;
fragmented = 1;
}
break;
case 'N':
if (strncmp(pkt, "NS", http_frag) == 0) {
if (is_fragmented)
*is_fragmented = 1;
return pkt + http_frag - 1;
method_end = pkt + http_frag - 1;
fragmented = 1;
}
break;
case 'L':
if (strncmp(pkt, "LE", http_frag) == 0) {
if (is_fragmented)
*is_fragmented = 1;
return pkt + http_frag - 1;
method_end = pkt + http_frag - 1;
fragmented = 1;
}
break;
case 'R':
if (strncmp(pkt, "RACE", http_frag + 1) == 0) {
if (is_fragmented)
*is_fragmented = 1;
return pkt + http_frag - 1;
method_end = pkt + http_frag - 1;
fragmented = 1;
}
break;
case 'O':
if (strncmp(pkt, "ONNECT", http_frag + 1) == 0) {
if (is_fragmented)
*is_fragmented = 1;
return pkt + http_frag - 1;
method_end = pkt + http_frag - 1;
fragmented = 1;
}
break;
default:
return NULL;
break;
}
}
if (method_end != NULL && is_fragmented != NULL) {
*is_fragmented = fragmented;
}
return NULL;
return method_end;
}
/** Fragment and send the packet.
*
* This function cuts off the end of the packet (step=0) or
@ -575,8 +560,7 @@ static void send_native_fragment(HANDLE w_filter, WINDIVERT_ADDRESS addr,
return;
}
switch(step) {
case 0:
if (step == 0) {
if (packet_v4)
ppIpHdr->Length = htons(
ntohs(ppIpHdr->Length) -
@ -588,8 +572,7 @@ static void send_native_fragment(HANDLE w_filter, WINDIVERT_ADDRESS addr,
packet_dataLen + fragment_size
);
packetLen = packetLen - packet_dataLen + fragment_size;
break;
case 1:
} else if (step == 1) {
if (packet_v4)
ppIpHdr->Length = htons(
ntohs(ppIpHdr->Length) - fragment_size
@ -604,7 +587,6 @@ static void send_native_fragment(HANDLE w_filter, WINDIVERT_ADDRESS addr,
packetLen -= fragment_size;
ppTcpHdr->SeqNum = htonl(ntohl(ppTcpHdr->SeqNum) + fragment_size);
break;
}
addr.IPChecksum = 0;

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