我正在尝试在VPS服务器上运行GnuTLS示例。我收到这个错误：
[root@localhost test]# ./server
Echo Server ready. Listening to port '5556'.
- connection from 127.0.0.1, port 38140
*** glibc detected *** ./server: double free or corruption (fasttop): 0x09a9e5c0 ***
======= Backtrace: =========
/lib/libc.so.6(+0x6ea31)[0xc32a31]
/usr/local/lib/libgnutls.so.28(+0x90bd9)[0x6dbbd9]
/usr/local/lib/libgnutls.so.28(+0x9095a)[0x6db95a]
/usr/local/lib/libgnutls.so.28(+0x1e878)[0x669878]
/usr/local/lib/libgnutls.so.28(+0x1c1a8)[0x6671a8]
/usr/local/lib/libgnutls.so.28(gnutls_handshake+0x47)[0x667937]
./server[0x8049040]
/lib/libc.so.6(__libc_start_main+0xe6)[0xbdace6]
./server[0x8048c51]
======= Memory map: ========
00452000-00469000 r-xp 00000000 fd:00 131073 /lib/libpthread-2.12.so
00469000-0046a000 r--p 00016000 fd:00 131073 /lib/libpthread-2.12.so
0046a000-0046b000 rw-p 00017000 fd:00 131073 /lib/libpthread-2.12.so
0046b000-0046d000 rw-p 00000000 00:00 0
0062b000-0062c000 r-xp 00000000 00:00 0 [vdso]
0064b000-00733000 r-xp 00000000 fd:00 18887 /usr/local/lib/libgnutls.so.28.3.0
00733000-00739000 rw-p 000e7000 fd:00 18887 /usr/local/lib/libgnutls.so.28.3.0
00947000-0094e000 r-xp 00000000 fd:00 131077 /lib/librt-2.12.so
0094e000-0094f000 r--p 00006000 fd:00 131077 /lib/librt-2.12.so
0094f000-00950000 rw-p 00007000 fd:00 131077 /lib/librt-2.12.so
00a64000-00a82000 r-xp 00000000 fd:00 131042 /lib/ld-2.12.so
00a82000-00a83000 r--p 0001d000 fd:00 131042 /lib/ld-2.12.so
00a83000-00a84000 rw-p 0001e000 fd:00 131042 /lib/ld-2.12.so
00bc4000-00d4d000 r-xp 00000000 fd:00 131049 /lib/libc-2.12.so
00d4d000-00d4e000 ---p 00189000 fd:00 131049 /lib/libc-2.12.so
00d4e000-00d50000 r--p 00189000 fd:00 131049 /lib/libc-2.12.so
00d50000-00d51000 rw-p 0018b000 fd:00 131049 /lib/libc-2.12.so
00d51000-00d54000 rw-p 00000000 00:00 0
00f13000-00f5f000 r-xp 00000000 fd:00 4823 /usr/lib/sse2/libgmp.so.3.5.0
00f5f000-00f62000 rw-p 0004b000 fd:00 4823 /usr/lib/sse2/libgmp.so.3.5.0
00fbf000-00fdc000 r-xp 00000000 fd:00 131015 /lib/libgcc_s-4.4.6-20110824.so.1
00fdc000-00fdd000 rw-p 0001d000 fd:00 131015 /lib/libgcc_s-4.4.6-20110824.so.1
08048000-0804a000 r-xp 00000000 fd:00 281891 /opt/test/server
0804a000-0804b000 rw-p 00001000 fd:00 281891 /opt/test/server
09a91000-09ab2000 rw-p 00000000 00:00 0 [heap]
b78ea000-b78ec000 rw-p 00000000 00:00 0
b78f0000-b78f5000 rw-p 00000000 00:00 0
bffc6000-bffdb000 rw-p 00000000 00:00 0 [stack]
Aborted
[root@localhost test]#
我是C编程的新手。你能告诉我这意味着什么吗？
p.s这是代码：
/* 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>
#define SRP_PASSWD "/opt/test/tpasswd"
#define SRP_PASSWD_CONF "/opt/test/tpasswd.conf"
#define KEYFILE "/opt/test/key.pem"
#define CERTFILE "/opt/test/cert.pem"
#define CAFILE "/etc/ssl/certs/ca-certificates.crt"
/* This is a sample TLS-SRP echo server.
*/
#define SOCKET_ERR(err,s) if(err==-1) {perror(s);return(1);}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */
/* These are global */
gnutls_srp_server_credentials_t srp_cred;
gnutls_certificate_credentials_t cert_cred;
static gnutls_session_t
initialize_tls_session (void)
{
gnutls_session_t session;
gnutls_init (&session, GNUTLS_SERVER);
gnutls_priority_set_direct (session, "NORMAL:-KX-ALL:+SRP:+SRP-DSS:+SRP-RSA", NULL);
gnutls_credentials_set (session, GNUTLS_CRD_SRP, srp_cred);
/* for the certificate authenticated ciphersuites.
*/
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, cert_cred);
/* request client certificate if any.
*/
gnutls_certificate_server_set_request (session, GNUTLS_CERT_IGNORE);
return session;
}
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;
char buffer[MAX_BUF + 1];
int optval = 1;
char name[256];
strcpy (name, "Echo Server");
gnutls_global_init ();
/* SRP_PASSWD a password file (created with the included srptool utility)
*/
gnutls_srp_allocate_server_credentials (&srp_cred);
gnutls_srp_set_server_credentials_file (srp_cred, SRP_PASSWD,
SRP_PASSWD_CONF);
gnutls_certificate_allocate_credentials (&cert_cred);
gnutls_certificate_set_x509_trust_file (cert_cred, CAFILE,
GNUTLS_X509_FMT_PEM);
gnutls_certificate_set_x509_key_file (cert_cred, CERTFILE, KEYFILE,
GNUTLS_X509_FMT_PEM);
/* TCP 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 ("%s ready. Listening to port '%d'.\n\n", name, PORT);
client_len = sizeof (sa_cli);
for (;;)
{
session = initialize_tls_session ();
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_ptr (session, (gnutls_transport_ptr_t) 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");
printf ("- User %s was connected\n", gnutls_srp_server_get_username(session));
/* print_info(session); */
for (;;)
{
memset (buffer, 0, MAX_BUF + 1);
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("\n- Peer has closed the GnuTLS connection\n");
break;
}
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, buffer, strlen (buffer));
}
}
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_srp_free_server_credentials (srp_cred);
gnutls_certificate_free_credentials (cert_cred);
gnutls_global_deinit ();
return 0;
}
我使用此命令编译代码
gcc -o server ex-serv-srp.c -lgnutls
此致
答案 0 :(得分：1)
“double free”表示您试图两次释放（）一段数据。
如果没有看到您正在编译的代码，很难说更多。
作为一般规则：如果你可以使用调试符号编译程序（它现在似乎没有它们）并从程序中获取核心转储，你可以使用gdb来获取堆栈跟踪并找出违规代码的确切行。 （你也可以直接在gdb下运行程序。）
在这种情况下确保你的代码在使用-Wall和-Werror运行gcc时能够干净地编译是很有价值的 - 它们会遇到很多问题。