Debug

//------------------------------------------------------------------------------------------
//DEFINING 3 STRUCTURES HERE
//------------------------------------------------------------------------------------------
typedef struct _SslDecryptSession {
    guchar _master_secret[SSL_MASTER_SECRET_LENGTH];
    guchar _session_id[256];
    guchar _client_random[32];
    guchar _server_random[32];
    StringInfo session_id;
    StringInfo session_ticket;
    StringInfo server_random;
    StringInfo client_random;
    StringInfo master_secret;
    StringInfo handshake_data;
    /* the data store for this StringInfo must be allocated explicitly with a capture lifetime scope */
    StringInfo pre_master_secret;
    guchar _server_data_for_iv[24];
    StringInfo server_data_for_iv;
    guchar _client_data_for_iv[24];
    StringInfo client_data_for_iv;

    gint state;
    SslCipherSuite cipher_suite;
    SslDecoder *server;
    SslDecoder *client;
    SslDecoder *server_new;
    SslDecoder *client_new;
#if defined(HAVE_LIBGNUTLS) && defined(HAVE_LIBGCRYPT)
    gcry_sexp_t private_key;
#endif
    StringInfo psk;
    guint16 version_netorder;
    StringInfo app_data_segment;
    SslSession session;

} SslDecryptSession;


/* XXX Should we use GByteArray instead? */
typedef struct _StringInfo {
    guchar  *data;      /* Backing storage which may be larger than data_len */
    guint    data_len;  /* Length of the meaningful part of data */
} StringInfo

typedef struct _SslSession {
    gint cipher;
    gint compression;
    guint32 version;
    gint8 client_cert_type;
    gint8 server_cert_type;

    /* The address/proto/port of the server as determined from heuristics
     * (e.g. ClientHello) or set externally (via ssl_set_master_secret()). */
    address srv_addr;
    port_type srv_ptype;
    guint srv_port;

    /* The Application layer protocol if known (for STARTTLS support) */
    dissector_handle_t   app_handle;
    guint32              last_nontls_frame;
    gboolean             is_session_resumed;
} SslSession;


//------------------------------------------------------------------------------------------
//Somewhere in the main function, The piece of code I am executing
//------------------------------------------------------------------------------------------

        SslDecryptSession *ssl_session = malloc(sizeof(struct _SslDecryptSession ));
         ssl_session->client_random.data = NULL;
         ssl_session->server_random.data= NULL;
        const u_char *payload;                  /* Packet payload */
            //Case for client random
            printf("Client Random ");
            for (cs_id = 11; cs_id < 43; cs_id++){
                    printf("%hhX", payload[cs_id] );
            }
            printf("\n");


            cs_id=11;
            ssl_session->client_random.data_len=32;
            // Segmentation fault here
            memcpy(ssl_session->client_random.data, payload[cs_id], 32);


/* More error debug from gdb


b 1985    // Putting a break point at line 1985 in my source code.
     //Here this is eqvialent to line 83, that is "ssl_session->client_random.data_len=32;"
Breakpoint 1 at 0x403878: file Newversion.c, line 1985.

run       //run the code in gdb

At breakpoint 1 the following info is in the variables


p ssl_session
$1 = (SslDecryptSession *) 0x60fc50   // I put some data in ssl_session->version_netorder earlier. So it is not null here. Everything works fine here

p ssl_session->client_random.data
$2 = (guchar *) 0x0

p ssl_session->client_random.data_len
$3 = 32

step  // Execute 1 more line in the code

// I reach at the memcpy line and I get this error then

Breakpoint 1, got_packet (args=0x0, header=0x7fffffffe2c0, packet=0x7ffff6939086 "P=\345\203\376\177") at Newversion.c:1995
1995                memcpy(ssl_session->client_random.data, payload[cs_id], 32);
(gdb)
(gdb) s
__memcpy_sse2_unaligned () at ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S:27
27  ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S: No such file or directory.
(gdb)
28  in ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S
(gdb)
29  in ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S
(gdb)
30  in ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S
(gdb)
31  in ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S
(gdb)
32  in ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S
(gdb)
33  in ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S
(gdb)
34  in ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S
(gdb)
35  in ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S
(gdb)

Program received signal SIGSEGV, Segmentation fault.
__memcpy_sse2_unaligned () at ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S:35
35  in ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S



*/