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|
/* desocket library by Marc "vanHauser" Heuse <vh@thc.org>
*
* Use this library for fuzzing if preeny's desock and desock2 solutions
* do not work for you - these would provide faster performance.
*
*/
// default: file descriptor 0 for stdin
#define FUZZ_INPUT_FD 0
#include <dlfcn.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static void *handle;
static bool do_fork, do_close, debug, running;
static int port = -1;
static int listen_fd = -1;
struct myin_addr {
unsigned int s_addr; // IPv4 address in network byte order
};
struct mysockaddr {
unsigned short int sin_family; // Address family: AF_INET
unsigned short int sin_port; // Port number (network byte order)
struct myin_addr sin_addr; // Internet address
char sin_zero[8]; // Padding (unused)
};
#define RTLD_LAZY 0x00001
unsigned short int htons(unsigned short int hostshort) {
return (hostshort << 8) | (hostshort >> 8);
}
static void __get_handle() {
if (!(handle = dlopen("libc.so", RTLD_NOW))) {
if (!(handle = dlopen("libc.so.6", RTLD_NOW))) {
if (!(handle = dlopen("libc-orig.so", RTLD_LAZY))) {
if (!(handle = dlopen("cygwin1.dll", RTLD_LAZY))) {
if (!(handle = dlopen("libc.so", RTLD_NOW))) {
fprintf(stderr, "DESOCK: can not find libc!\n");
exit(-1);
}
}
}
}
}
if (getenv("DESOCK_DEBUG")) { debug = true; }
if (getenv("DESOCK_PORT")) { port = atoi(getenv("DESOCK_PORT")); }
if (getenv("DESOCK_FORK")) { do_fork = true; }
if (getenv("DESOCK_CLOSE_EXIT")) { do_close = true; }
if (debug) fprintf(stderr, "DESOCK: initialized!\n");
}
int (*o_shutdown)(int socket, int how);
int shutdown(int socket, int how) {
if (port != -1 && socket == FUZZ_INPUT_FD && running) {
running = false;
if (do_close) {
if (debug) fprintf(stderr, "DESOCK: exiting\n");
_exit(0);
}
}
if (port == -1 && do_close) {
if (debug) fprintf(stderr, "DESOCK: exiting\n");
_exit(0);
}
if (!handle) { __get_handle(); }
if (!o_shutdown) { o_shutdown = dlsym(handle, "shutdown"); }
return o_shutdown(socket, how);
}
int (*o_close)(int socket);
int close(int socket) {
if (port != -1 && socket == FUZZ_INPUT_FD && running) {
running = false;
if (do_close) {
if (debug) fprintf(stderr, "DESOCK: exiting\n");
_exit(0);
}
}
if (listen_fd != -1 && socket == listen_fd) {
if (debug) fprintf(stderr, "DESOCK: close bind\n");
listen_fd = -1;
}
if (!handle) { __get_handle(); }
if (!o_close) { o_close = dlsym(handle, "close"); }
return o_close(socket);
}
int (*o_fork)(void);
int fork() {
if (do_fork) {
if (debug) fprintf(stderr, "DESOCK: fake fork\n");
return 0;
}
if (!handle) { __get_handle(); }
if (!o_fork) { o_fork = dlsym(handle, "fork"); }
return o_fork();
}
int (*o_accept)(int sockfd, struct mysockaddr *addr,
unsigned long int *addrlen);
int accept(int sockfd, struct mysockaddr *addr, unsigned long int *addrlen) {
if (!handle) { __get_handle(); }
if (!o_accept) { o_accept = dlsym(handle, "accept"); }
if (!running && sockfd == listen_fd) {
if (debug) fprintf(stderr, "DESOCK: intercepted accept on %d\n", sockfd);
if (addr && addrlen) {
// we need to fill this!
memset(addr, 0, *addrlen);
addr->sin_family = 2; // AF_INET
addr->sin_port = htons(1023); // Port 1023 in network byte order
addr->sin_addr.s_addr = 0x0100007f;
}
running = true;
return FUZZ_INPUT_FD;
}
return o_accept(sockfd, addr, addrlen);
}
int accept4(int sockfd, struct mysockaddr *addr, unsigned long int *addrlen,
int flags) {
return accept(sockfd, addr, addrlen); // ignore flags
}
int (*o_listen)(int sockfd, int backlog);
int listen(int sockfd, int backlog) {
if (!handle) { __get_handle(); }
if (!o_listen) { o_listen = dlsym(handle, "listen"); }
if (sockfd == listen_fd) {
if (debug) fprintf(stderr, "DESOCK: intercepted listen on %d\n", sockfd);
return 0;
}
return o_listen(sockfd, backlog);
}
int (*o_bind)(int sockfd, const struct mysockaddr *addr,
unsigned long int addrlen);
int bind(int sockfd, const struct mysockaddr *addr, unsigned long int addrlen) {
if (!handle) { __get_handle(); }
if (!o_bind) { o_bind = dlsym(handle, "bind"); }
if (addr->sin_port == htons(port)) {
if (debug) fprintf(stderr, "DESOCK: intercepted bind on %d\n", sockfd);
listen_fd = sockfd;
return 0;
}
return o_bind(sockfd, addr, addrlen);
}
int (*o_setsockopt)(int sockfd, int level, int optname, const void *optval,
unsigned long int optlen);
int setsockopt(int sockfd, int level, int optname, const void *optval,
unsigned long int optlen) {
if (!handle) { __get_handle(); }
if (!o_setsockopt) { o_setsockopt = dlsym(handle, "setsockopt"); }
if (listen_fd == sockfd) {
if (debug)
fprintf(stderr, "DESOCK: intercepted setsockopt on %d for %d\n", sockfd,
optname);
return 0;
}
return o_setsockopt(sockfd, level, optname, optval, optlen);
}
int (*o_getsockopt)(int sockfd, int level, int optname, void *optval,
unsigned long int *optlen);
int getsockopt(int sockfd, int level, int optname, void *optval,
unsigned long int *optlen) {
if (!handle) { __get_handle(); }
if (!o_getsockopt) { o_getsockopt = dlsym(handle, "getsockopt"); }
if (listen_fd == sockfd) {
if (debug)
fprintf(stderr, "DESOCK: intercepted getsockopt on %d for %d\n", sockfd,
optname);
int *o = (int *)optval;
if (o != NULL) {
*o = 1; // let's hope this is fine
}
return 0;
}
return o_getsockopt(sockfd, level, optname, optval, optlen);
}
int (*o_getpeername)(int sockfd, struct mysockaddr *addr,
unsigned long int *addrlen);
int getpeername(int sockfd, struct mysockaddr *addr,
unsigned long int *addrlen) {
if (!handle) { __get_handle(); }
if (!o_getpeername) { o_getpeername = dlsym(handle, "getpeername"); }
if (port != -1 && sockfd == FUZZ_INPUT_FD) {
if (debug) fprintf(stderr, "DESOCK: getpeername\n");
if (addr && addrlen) {
// we need to fill this!
memset(addr, 0, *addrlen);
addr->sin_family = 2; // AF_INET
addr->sin_port = htons(1023); // Port 1023 in network byte order
addr->sin_addr.s_addr = 0x0100007f;
}
return 0;
}
return o_getpeername(sockfd, addr, addrlen);
}
int (*o_getsockname)(int sockfd, struct mysockaddr *addr,
unsigned long int *addrlen);
int getsockname(int sockfd, struct mysockaddr *addr,
unsigned long int *addrlen) {
if (!handle) { __get_handle(); }
if (!o_getsockname) { o_getsockname = dlsym(handle, "getsockname"); }
if (port != -1 && sockfd == FUZZ_INPUT_FD) {
if (debug) fprintf(stderr, "DESOCK: getsockname\n");
if (addr && addrlen) {
// we need to fill this!
memset(addr, 0, *addrlen);
addr->sin_family = 2; // AF_INET
addr->sin_port = htons(port);
addr->sin_addr.s_addr = 0x0100007f;
}
return 0;
}
return o_getsockname(sockfd, addr, addrlen);
}
static FILE *(*o_fdopen)(int fd, const char *mode);
FILE *fdopen(int fd, const char *mode) {
if (!o_fdopen) {
if (!handle) { __get_handle(); }
o_fdopen = dlsym(handle, "fdopen");
if (!o_fdopen) {
fprintf(stderr, "%s(): can not find fdopen\n", dlerror());
exit(-1);
}
}
if (fd == FUZZ_INPUT_FD && strcmp(mode, "r") != 0) {
if (debug) fprintf(stderr, "DESOCK: intercepted fdopen(r+) for %d\n", fd);
return o_fdopen(fd, "r");
}
return o_fdopen(fd, mode);
}
/* TARGET SPECIFIC HOOKS - put extra needed code for your target here */
|
