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implement MSG_TRUNC logic in recvfrom and recvmsg

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hugoc 2024-02-02 16:39:32 +01:00
parent a47f9c0576
commit e379a8af75
1 changed files with 56 additions and 48 deletions
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104
src/libproxychains.c
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@ -1754,6 +1754,8 @@ HOOKFUNC(ssize_t, recvmsg, int sockfd, struct msghdr *msg, int flags){
char buffer[RECV_BUFFER_SIZE]; //buffer to receive and decapsulate a UDP relay packet
size_t bytes_received;
int trunc = flags & MSG_TRUNC;
struct sockaddr_storage from;
@ -1779,6 +1781,9 @@ HOOKFUNC(ssize_t, recvmsg, int sockfd, struct msghdr *msg, int flags){
PDEBUG("true_recvmsg returned -1, errno: %d, %s\n", errno,strerror(errno));
return -1;
}
if(RECV_BUFFER_SIZE == bytes_received){
PDEBUG("UDP PACKET SHOULD NOT BE THAT BIG\n");
}
// Transfer the fields we do not manage
@ -1802,7 +1807,7 @@ HOOKFUNC(ssize_t, recvmsg, int sockfd, struct msghdr *msg, int flags){
msg->msg_namelen = min;
}
return written;
return trunc?bytes_received:written; //if MSG_TRUNC flag is set, return the real length of the packet/datagram even when it was longer than the passed buffer (msg->msg_iov)
}
PDEBUG("packet received from the proxy chain's head\n");
@ -1884,7 +1889,7 @@ HOOKFUNC(ssize_t, recvmsg, int sockfd, struct msghdr *msg, int flags){
PDEBUG("Successful recvmsg() hook\n\n");
return udp_data_len;
return trunc?udp_data_len:written;//if MSG_TRUNC flag is set, return the real length of the packet/datagram even when it was longer than the passed buffer (msg->msg_iov)
}
@ -1936,24 +1941,29 @@ HOOKFUNC(ssize_t, recvfrom, int sockfd, void *buf, size_t len, int flags,
}
PDEBUG("sockfd %d is associated with udp_relay_chain %x\n", sockfd, relay_chain);
// On lance un receive_udp_packet()
char tmp_buffer[65535]; //maximum theoretical size of a UDP packet.
char buffer[RECV_BUFFER_SIZE]; //maximum theoretical size of a UDP packet.
int bytes_received;
ip_type src_ip;
unsigned short src_port;
int trunc = flags & MSG_TRUNC;
struct sockaddr_storage from;
socklen_t from_len = sizeof(from);
bytes_received = true_recvfrom(sockfd, tmp_buffer, sizeof(tmp_buffer), flags, (struct sockaddr*)&from, &from_len);
bytes_received = true_recvfrom(sockfd, buffer, sizeof(buffer), flags, (struct sockaddr*)&from, &from_len);
if(-1 == bytes_received){
PDEBUG("true_recvfrom returned -1\n");
return -1;
}
if(RECV_BUFFER_SIZE == bytes_received){
PDEBUG("UDP PACKET SHOULD NOT BE THAT BIG\n");
}
PDEBUG("successful recvfrom(), %d bytes received\n", bytes_received);
PDEBUG("packet: ");
DUMP_BUFFER(tmp_buffer, bytes_received);
DUMP_BUFFER(buffer, bytes_received);
//Check that the packet was received from the first relay of the chain
// i.e. does from == chain.head.bnd_addr ?
@ -1963,27 +1973,27 @@ HOOKFUNC(ssize_t, recvfrom, int sockfd, void *buf, size_t len, int flags,
PDEBUG("UDP packet not received from the proxy chain's head, transfering it as is\n");
int min = (bytes_received <= len)?bytes_received:len;
memcpy(buf, tmp_buffer, min);
memcpy(buf, buffer, min);
if(src_addr != NULL){ //TODO: check that the address copy is done correctly
socklen_t min_addr_len = (from_len<*addrlen)?from_len:*addrlen;
memcpy(src_addr, &from, min_addr_len);
*addrlen = min_addr_len;
}
return min;
return trunc?bytes_received:min; //if MSG_TRUNC flag is set, return the real length of the packet/datagram even when it was longer than the passed buffer (buf)
}
PDEBUG("packet received from the proxy chain's head\n");
int rc;
void* udp_data = NULL;
size_t udp_data_len = 0;
rc = unsocksify_udp_packet(tmp_buffer, bytes_received, *relay_chain, &src_ip, &src_port, &udp_data);
rc = unsocksify_udp_packet(buffer, bytes_received, *relay_chain, &src_ip, &src_port, &udp_data);
if(rc != SUCCESS){
PDEBUG("error unsocksifying the UDP packet\n");
return -1;
}
PDEBUG("UDP packet successfully unsocksifyied\n");
udp_data_len = bytes_received - (udp_data - (void*)tmp_buffer);
udp_data_len = bytes_received - (udp_data - (void*)buffer);
@ -2004,52 +2014,50 @@ HOOKFUNC(ssize_t, recvfrom, int sockfd, void *buf, size_t len, int flags,
// la retrouver ? -> done in unsocksify_udp_packet()
if (src_addr == NULL){ // No need to fill src_addr in this case
return udp_data_len;
}
struct sockaddr_in* src_addr_v4;
struct sockaddr_in6* src_addr_v6;
if(src_addr != NULL){ // No need to fill src_addr if the passed pointer is NULL
struct sockaddr_in* src_addr_v4;
struct sockaddr_in6* src_addr_v6;
//TODO bien gérer le controle de la taille de la src_addr fournie et le retour dans addrlen
//
//TODO bien gérer le controle de la taille de la src_addr fournie et le retour dans addrlen
//
if(src_ip.is_v6 && is_v4inv6((struct in6_addr*)src_ip.addr.v6)){
PDEBUG("src_ip is v4 in v6 ip\n");
if(addrlen < sizeof(struct sockaddr_in)){
PDEBUG("addrlen too short for ipv4\n");
if(src_ip.is_v6 && is_v4inv6((struct in6_addr*)src_ip.addr.v6)){
PDEBUG("src_ip is v4 in v6 ip\n");
if(addrlen < sizeof(struct sockaddr_in)){
PDEBUG("addrlen too short for ipv4\n");
}
src_addr_v4 = (struct sockaddr_in*)src_addr;
src_addr_v4->sin_family = AF_INET;
src_addr_v4->sin_port = src_port;
memcpy(&(src_addr_v4->sin_addr.s_addr), src_ip.addr.v6+12, 4);
*addrlen = sizeof(src_addr_v4);
}
src_addr_v4 = (struct sockaddr_in*)src_addr;
src_addr_v4->sin_family = AF_INET;
src_addr_v4->sin_port = src_port;
memcpy(&(src_addr_v4->sin_addr.s_addr), src_ip.addr.v6+12, 4);
*addrlen = sizeof(src_addr_v4);
}
else if(src_ip.is_v6){
PDEBUG("src_ip is true v6\n");
if(addrlen < sizeof(struct sockaddr_in6)){
PDEBUG("addrlen too short for ipv6\n");
return -1;
else if(src_ip.is_v6){
PDEBUG("src_ip is true v6\n");
if(addrlen < sizeof(struct sockaddr_in6)){
PDEBUG("addrlen too short for ipv6\n");
return -1;
}
src_addr_v6 = (struct sockaddr_in6*)src_addr;
src_addr_v6->sin6_family = AF_INET6;
src_addr_v6->sin6_port = src_port;
memcpy(src_addr_v6->sin6_addr.s6_addr, src_ip.addr.v6, 16);
*addrlen = sizeof(src_addr_v6);
}else {
if(addrlen < sizeof(struct sockaddr_in)){
PDEBUG("addrlen too short for ipv4\n");
}
src_addr_v4 = (struct sockaddr_in*)src_addr;
src_addr_v4->sin_family = AF_INET;
src_addr_v4->sin_port = src_port;
src_addr_v4->sin_addr.s_addr = (in_addr_t) src_ip.addr.v4.as_int;
*addrlen = sizeof(src_addr_v4);
}
src_addr_v6 = (struct sockaddr_in6*)src_addr;
src_addr_v6->sin6_family = AF_INET6;
src_addr_v6->sin6_port = src_port;
memcpy(src_addr_v6->sin6_addr.s6_addr, src_ip.addr.v6, 16);
*addrlen = sizeof(src_addr_v6);
}else {
if(addrlen < sizeof(struct sockaddr_in)){
PDEBUG("addrlen too short for ipv4\n");
}
src_addr_v4 = (struct sockaddr_in*)src_addr;
src_addr_v4->sin_family = AF_INET;
src_addr_v4->sin_port = src_port;
src_addr_v4->sin_addr.s_addr = (in_addr_t) src_ip.addr.v4.as_int;
*addrlen = sizeof(src_addr_v4);
}
PDEBUG("Successful recvfrom() hook\n\n");
return udp_data_len;
return trunc?udp_data_len:min; //if MSG_TRUNC flag is set, return the real length of the packet/datagram even when it was longer than the passed buffer (buf)
}
HOOKFUNC(ssize_t, send, int sockfd, const void *buf, size_t len, int flags){