问题描述
我正在使用 gnutls.org 中提供的匿名 TLS 连接代码。 服务器在ubuntu机器上实现，客户端是ARM Cortex A8嵌入式设备。服务器和客户端在同一个局域网内。
每次客户端开始连接时，都会在握手期间生成错误 (-58)，这意味着 GNUTLS_E_RECEIVED_ILLEgal_EXTENSION，即“收到了非法的 TLS 扩展。”。
从服务器端我得到错误：
但是，当我在 ubuntu 机器上同时运行服务器和客户端时（我在客户端中使用环回地址作为目的地），一切都很好。
同样，如果我在嵌入式板上同时运行服务器和客户端（始终将环回地址作为客户端中的目标），一切都很好。
嵌入式开发板使用 3.6.4 版的 gnutls。在 ubuntu 主机中有 gnutls 3.6.13。
有没有办法找到“非法”的 tls 扩展名？
这是错误交易的wireshark捕获：
"No.","Time","Source","Destination","Protocol","Length","Info"
"148","22.907515133","192.168.0.47","192.168.0.184","TCP","74","53378 > 2525 [SYN] Seq=0 Win=29200 Len=0 MSS=1460 SACK_PERM=1 TSval=2912635975 TSecr=0 WS=32"
"149","22.907546972","2525 > 53378 [SYN,ACK] Seq=0 Ack=1 Win=65160 Len=0 MSS=1460 SACK_PERM=1 TSval=2543059266 TSecr=2912635975 WS=128"
"150","22.908244578","66","53378 > 2525 [ACK] Seq=1 Ack=1 Win=29216 Len=0 TSval=2912635976 TSecr=2543059266"
"151","22.909329144","TLSv1.2","232","Client Hello"
"152","22.909344645","2525 > 53378 [ACK] Seq=1 Ack=167 Win=65024 Len=0 TSval=2543059267 TSecr=2912635977"
"153","22.909772038","259","Server Hello,Server Key Exchange,Server Hello Done"
"154","22.910430333","53378 > 2525 [ACK] Seq=167 Ack=194 Win=30272 Len=0 TSval=2912635978 TSecr=2543059268"
"155","22.911259314","53378 > 2525 [RST,ACK] Seq=167 Ack=194 Win=30272 Len=0 TSval=2912635979 TSecr=2543059268"
Wireshark 捕获的环回成功交易：
"No.","Info"
"1","0.000000000","127.0.0.1","48226 > 2525 [SYN] Seq=0 Win=65495 Len=0 MSS=65495 SACK_PERM=1 TSval=4110066202 TSecr=0 WS=128"
"2","0.000015551","2525 > 48226 [SYN,ACK] Seq=0 Ack=1 Win=65483 Len=0 MSS=65495 SACK_PERM=1 TSval=4110066202 TSecr=4110066202 WS=128"
"3","0.000029625","48226 > 2525 [ACK] Seq=1 Ack=1 Win=65536 Len=0 TSval=4110066202 TSecr=4110066202"
"4","0.000149840","236","Client Hello"
"5","0.000156259","2525 > 48226 [ACK] Seq=1 Ack=171 Win=65408 Len=0 TSval=4110066202 TSecr=4110066202"
"6","0.000390203",Server Hello Done"
"7","0.000434564","48226 > 2525 [ACK] Seq=171 Ack=194 Win=65408 Len=0 TSval=4110066202 TSecr=4110066202"
"8","0.001128440","220","Client Key Exchange,Change Cipher Spec,Encrypted Handshake Message"
"9","0.001174055","2525 > 48226 [ACK] Seq=194 Ack=325 Win=65408 Len=0 TSval=4110066203 TSecr=4110066203"
"10","0.001695368","145","Change Cipher Spec,Encrypted Handshake Message"
"11","0.001739096","48226 > 2525 [ACK] Seq=325 Ack=273 Win=65536 Len=0 TSval=4110066204 TSecr=4110066204"
"12","0.001880330","139","Application Data"
"13","0.001885804","2525 > 48226 [ACK] Seq=273 Ack=398 Win=65536 Len=0 TSval=4110066204 TSecr=4110066204"
"14","0.001942348","Application Data"
"15","0.001947752","48226 > 2525 [ACK] Seq=398 Ack=346 Win=65536 Len=0 TSval=4110066204 TSecr=4110066204"
"16","0.002100239","123","Encrypted Alert"
"17","0.002105316","2525 > 48226 [ACK] Seq=346 Ack=455 Win=65536 Len=0 TSval=4110066204 TSecr=4110066204"
"18","0.002188593","Encrypted Alert"
"19","0.002193722","48226 > 2525 [ACK] Seq=455 Ack=403 Win=65536 Len=0 TSval=4110066204 TSecr=4110066204"
"20","0.002243619","2525 > 48226 [FIN,ACK] Seq=403 Ack=455 Win=65536 Len=0 TSval=4110066204 TSecr=4110066204"
"21","0.002278856","48226 > 2525 [FIN,ACK] Seq=455 Ack=404 Win=65536 Len=0 TSval=4110066204 TSecr=4110066204"
"22","0.002287692","2525 > 48226 [ACK] Seq=404 Ack=456 Win=65536 Len=0 TSval=4110066204 TSecr=4110066204"
这里是客户端的代码：
int tlsSendPacket_anonymous(void)
{
int ret,sd,ii;
gnutls_certificate_type_t gnu_certificate_type;
gnutls_anon_client_credentials_t anoncred;
/* Need to enable anonymous KX specifically. */
//moved before thread start
//gnutls_global_init();
ret = gnutls_anon_allocate_client_credentials(&anoncred);
if (GNUTLS_E_SUCCESS != ret)
{
SEND_MESSAGE(DBG_ERROR,"TLS ALLOCATION ERROR\n");
return ret;
}
/* Initialize TLS session
*/
ret = gnutls_init(&session,GNUTLS_CLIENT);
if (GNUTLS_E_SUCCESS != ret)
{
SEND_MESSAGE(DBG_ERROR,"TLS INIT ERROR\n");
return ret;
}
/* Use default priorities */
ret = gnutls_priority_set_direct(session,"PERFORMANCE:+ANON-ECDH:+ANON-DH",NULL);
if (GNUTLS_E_SUCCESS != ret)
{
SEND_MESSAGE(DBG_ERROR,"TLS PRIORITY SET ERROR\n");
return ret;
}
/* put the anonymous credentials to the current session
*/
ret = gnutls_credentials_set(session,GNUTLS_CRD_ANON,anoncred);
if (GNUTLS_E_SUCCESS != ret)
{
SEND_MESSAGE(DBG_ERROR,"TLS CREDENTIAL SET ERROR\n");
return ret;
}
/* connect to the peer
*/
sd = tcp_connect();
if (sd <= 0)
{
SEND_MESSAGE(DBG_ERROR,"TLS TCP CONNECTION ERROR\n");
return sd;
}
gnutls_transport_set_int(session,sd);
gnutls_handshake_set_timeout(session,GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
/* Perform the TLS handshake
*/
do {
ret = gnutls_handshake(session);
}
while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
if (ret < 0) {
fprintf(stderr,"*** Handshake Failed\n");
gnutls_perror(ret);
goto end;
} else {
char *desc;
desc = gnutls_session_get_desc(session);
printf("- Session info: %s\n",desc);
gnutls_free(desc);
}
LOOP_CHECK(ret,gnutls_record_send(session,MSG,strlen(MSG)));
LOOP_CHECK(ret,gnutls_record_recv(session,buffer,MAX_BUF));
if (ret == 0) {
printf("- Peer has closed the TLS connection\n");
goto end;
} else if (ret < 0 && gnutls_error_is_fatal(ret) == 0) {
fprintf(stderr,"*** Warning: %s\n",gnutls_strerror(ret));
} else if (ret < 0) {
fprintf(stderr,"*** Error: %s\n",gnutls_strerror(ret));
goto end;
}
if (ret > 0) {
printf("- Received %d bytes: ",ret);
for (ii = 0; ii < ret; ii++) {
fputc(buffer[ii],stdout);
}
fputs("\n",stdout);
}
LOOP_CHECK(ret,gnutls_bye(session,GNUTLS_SHUT_RDWR));
end:
tcp_close(sd);
gnutls_deinit(session);
gnutls_anon_free_client_credentials(anoncred);
//Moved at thread end
//gnutls_global_deinit();
return 0;
}
和服务器：
/* This example code is placed in the public domain. */
#ifdef HAVE_CONfig_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
/* This is a sample TLS 1.0 echo server,for anonymous authentication only.
*/
#define SOCKET_ERR(err,s) if(err==-1) {perror(s);return(1);}
#define MAX_BUF 1024
#define PORT 2525 //5556 /* listen to 5556 port */
int main(void)
{
int err,listen_sd;
int sd,ret;
struct sockaddr_in sa_serv;
struct sockaddr_in sa_cli;
socklen_t client_len;
char topbuf[512];
gnutls_session_t session;
gnutls_anon_server_credentials_t anoncred;
char buffer[MAX_BUF + 1];
int optval = 1;
if (gnutls_check_version("3.1.4") == NULL) {
fprintf(stderr,"GnuTLS 3.1.4 or later is required for this example\n");
exit(1);
}
/* for backwards compatibility with gnutls < 3.3.0 */
gnutls_global_init();
gnutls_anon_allocate_server_credentials(&anoncred);
gnutls_anon_set_server_kNown_dh_params(anoncred,GNUTLS_SEC_ParaM_MEDIUM);
/* Socket operations
*/
listen_sd = socket(AF_INET,SOCK_STREAM,0);
SOCKET_ERR(listen_sd,"socket");
memset(&sa_serv,'\0',sizeof(sa_serv));
sa_serv.sin_family = AF_INET;
sa_serv.sin_addr.s_addr = INADDR_ANY;
sa_serv.sin_port = htons(PORT); /* Server Port number */
setsockopt(listen_sd,SOL_SOCKET,SO_REUSEADDR,(void *) &optval,sizeof(int));
err =
bind(listen_sd,(struct sockaddr *) &sa_serv,sizeof(sa_serv));
SOCKET_ERR(err,"bind");
err = listen(listen_sd,1024);
SOCKET_ERR(err,"listen");
printf("Server ready. Listening to port '%d'.\n\n",PORT);
client_len = sizeof(sa_cli);
for (;;) {
gnutls_init(&session,GNUTLS_SERVER);
gnutls_priority_set_direct(session,"norMAL:+ANON-ECDH:+ANON-DH",NULL);
gnutls_credentials_set(session,anoncred);
sd = accept(listen_sd,(struct sockaddr *) &sa_cli,&client_len);
printf("- connection from %s,port %d\n",inet_ntop(AF_INET,&sa_cli.sin_addr,topbuf,sizeof(topbuf)),ntohs(sa_cli.sin_port));
gnutls_transport_set_int(session,sd);
do {
ret = gnutls_handshake(session);
}
while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
if (ret < 0) {
close(sd);
gnutls_deinit(session);
fprintf(stderr,"*** Handshake has Failed (%s)\n\n",gnutls_strerror(ret));
continue;
}
printf("- Handshake was completed\n");
/* see the Getting peer's information example */
/* print_info(session); */
for (;;) {
ret = gnutls_record_recv(session,MAX_BUF);
if (ret == 0) {
printf
("\n- Peer has closed the GnuTLS connection\n");
break;
} else if (ret < 0
&& gnutls_error_is_fatal(ret) == 0) {
fprintf(stderr,gnutls_strerror(ret));
} else if (ret < 0) {
fprintf(stderr,"\n*** Received corrupted "
"data(%d). Closing the connection.\n\n",ret);
break;
} else if (ret > 0) {
/* echo data back to the client
*/
gnutls_record_send(session,ret);
}
}
printf("\n");
/* do not wait for the peer to close the connection.
*/
gnutls_bye(session,GNUTLS_SHUT_WR);
close(sd);
gnutls_deinit(session);
}
close(listen_sd);
gnutls_anon_free_server_credentials(anoncred);
gnutls_global_deinit();
return 0;
}
解决方法
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