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27af1d09df169170256490e475fdbf93d415b51d
nmap/ncat/util.c
d33tah 2fde134f36 fflush stderr in all messages sent by Ncat. This makes 
it more comfortable to test Ncat under Cygwin, which
doesn't fflush even if the message contains \n.
(At least not in my ssh+screen+zsh combination).
2013-09-12 14:23:24 +00:00

733 lines
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/***************************************************************************
* util.c -- Various utility functions. *
***********************IMPORTANT NMAP LICENSE TERMS************************
* *
* The Nmap Security Scanner is (C) 1996-2013 Insecure.Com LLC. Nmap is *
* also a registered trademark of Insecure.Com LLC. This program is free *
* software; you may redistribute and/or modify it under the terms of the *
* GNU General Public License as published by the Free Software *
* Foundation; Version 2 ("GPL"), BUT ONLY WITH ALL OF THE CLARIFICATIONS *
* AND EXCEPTIONS DESCRIBED HEREIN. This guarantees your right to use, *
* modify, and redistribute this software under certain conditions. If *
* you wish to embed Nmap technology into proprietary software, we sell *
* alternative licenses (contact sales@nmap.com). Dozens of software *
* vendors already license Nmap technology such as host discovery, port *
* scanning, OS detection, version detection, and the Nmap Scripting *
* Engine. *
* *
* Note that the GPL places important restrictions on "derivative works", *
* yet it does not provide a detailed definition of that term. To avoid *
* misunderstandings, we interpret that term as broadly as copyright law *
* allows. For example, we consider an application to constitute a *
* derivative work for the purpose of this license if it does any of the *
* following with any software or content covered by this license *
* ("Covered Software"): *
* *
* o Integrates source code from Covered Software. *
* *
* o Reads or includes copyrighted data files, such as Nmap's nmap-os-db *
* or nmap-service-probes. *
* *
* o Is designed specifically to execute Covered Software and parse the *
* results (as opposed to typical shell or execution-menu apps, which will *
* execute anything you tell them to). *
* *
* o Includes Covered Software in a proprietary executable installer. The *
* installers produced by InstallShield are an example of this. Including *
* Nmap with other software in compressed or archival form does not *
* trigger this provision, provided appropriate open source decompression *
* or de-archiving software is widely available for no charge. For the *
* purposes of this license, an installer is considered to include Covered *
* Software even if it actually retrieves a copy of Covered Software from *
* another source during runtime (such as by downloading it from the *
* Internet). *
* *
* o Links (statically or dynamically) to a library which does any of the *
* above. *
* *
* o Executes a helper program, module, or script to do any of the above. *
* *
* This list is not exclusive, but is meant to clarify our interpretation *
* of derived works with some common examples. Other people may interpret *
* the plain GPL differently, so we consider this a special exception to *
* the GPL that we apply to Covered Software. Works which meet any of *
* these conditions must conform to all of the terms of this license, *
* particularly including the GPL Section 3 requirements of providing *
* source code and allowing free redistribution of the work as a whole. *
* *
* As another special exception to the GPL terms, Insecure.Com LLC grants *
* permission to link the code of this program with any version of the *
* OpenSSL library which is distributed under a license identical to that *
* listed in the included docs/licenses/OpenSSL.txt file, and distribute *
* linked combinations including the two. *
* *
* Any redistribution of Covered Software, including any derived works, *
* must obey and carry forward all of the terms of this license, including *
* obeying all GPL rules and restrictions. For example, source code of *
* the whole work must be provided and free redistribution must be *
* allowed. All GPL references to "this License", are to be treated as *
* including the terms and conditions of this license text as well. *
* *
* Because this license imposes special exceptions to the GPL, Covered *
* Work may not be combined (even as part of a larger work) with plain GPL *
* software. The terms, conditions, and exceptions of this license must *
* be included as well. This license is incompatible with some other open *
* source licenses as well. In some cases we can relicense portions of *
* Nmap or grant special permissions to use it in other open source *
* software. Please contact fyodor@nmap.org with any such requests. *
* Similarly, we don't incorporate incompatible open source software into *
* Covered Software without special permission from the copyright holders. *
* *
* If you have any questions about the licensing restrictions on using *
* Nmap in other works, are happy to help. As mentioned above, we also *
* offer alternative license to integrate Nmap into proprietary *
* applications and appliances. These contracts have been sold to dozens *
* of software vendors, and generally include a perpetual license as well *
* as providing for priority support and updates. They also fund the *
* continued development of Nmap. Please email sales@nmap.com for further *
* information. *
* *
* If you have received a written license agreement or contract for *
* Covered Software stating terms other than these, you may choose to use *
* and redistribute Covered Software under those terms instead of these. *
* *
* Source is provided to this software because we believe users have a *
* right to know exactly what a program is going to do before they run it. *
* This also allows you to audit the software for security holes (none *
* have been found so far). *
* *
* Source code also allows you to port Nmap to new platforms, fix bugs, *
* and add new features. You are highly encouraged to send your changes *
* to the dev@nmap.org mailing list for possible incorporation into the *
* main distribution. By sending these changes to Fyodor or one of the *
* Insecure.Org development mailing lists, or checking them into the Nmap *
* source code repository, it is understood (unless you specify otherwise) *
* that you are offering the Nmap Project (Insecure.Com LLC) the *
* unlimited, non-exclusive right to reuse, modify, and relicense the *
* code. Nmap will always be available Open Source, but this is important *
* because the inability to relicense code has caused devastating problems *
* for other Free Software projects (such as KDE and NASM). We also *
* occasionally relicense the code to third parties as discussed above. *
* If you wish to specify special license conditions of your *
* contributions, just say so when you send them. *
* *
* This program is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Nmap *
* license file for more details (it's in a COPYING file included with *
* Nmap, and also available from https://svn.nmap.org/nmap/COPYING *
* *
***************************************************************************/
/* $Id$ */
#include "sys_wrap.h"
#include "util.h"
#include "ncat.h"
#include "nbase.h"
#include "sockaddr_u.h"
#include <stdio.h>
#ifdef WIN32
#include <iphlpapi.h>
#endif
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
/* safely add 2 size_t */
size_t sadd(size_t l, size_t r)
{
size_t t;
t = l + r;
if (t < l)
bye("integer overflow %lu + %lu.", (u_long) l, (u_long) r);
return t;
}
/* safely multiply 2 size_t */
size_t smul(size_t l, size_t r)
{
size_t t;
t = l * r;
if (l && t / l != r)
bye("integer overflow %lu * %lu.", (u_long) l, (u_long) r);
return t;
}
#ifdef WIN32
void windows_init()
{
WORD werd;
WSADATA data;
werd = MAKEWORD(2, 2);
if ((WSAStartup(werd, &data)) != 0)
bye("Failed to start WinSock.");
}
#endif
/* Use this to print debug or diagnostic messages to avoid polluting the user
stream. */
void loguser(const char *fmt, ...)
{
va_list ap;
fprintf(stderr, "%s: ", NCAT_NAME);
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fflush(stderr);
}
/* Log a user message without the "Ncat: " prefix, to allow building up a line
with a series of strings. */
void loguser_noprefix(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fflush(stderr);
}
void logdebug(const char *fmt, ...)
{
va_list ap;
fprintf(stderr, "NCAT DEBUG: ");
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fflush(stderr);
}
void logtest(const char *fmt, ...)
{
va_list ap;
fprintf(stderr, "NCAT TEST: ");
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fflush(stderr);
}
/* Exit status 2 indicates a program error other than a network error. */
void die(char *err)
{
perror(err);
fflush(stderr);
exit(2);
}
/* adds newline for you */
void bye(const char *fmt, ...)
{
va_list ap;
fprintf(stderr, "%s: ", NCAT_NAME);
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fprintf(stderr, " QUITTING.\n");
fflush(stderr);
exit(2);
}
/* zero out some mem, bzero() is deprecated */
void zmem(void *mem, size_t n)
{
memset(mem, 0, n);
}
/* Append n bytes starting at s to a malloc-allocated buffer. Reallocates the
buffer and updates the variables to make room if necessary. */
int strbuf_append(char **buf, size_t *size, size_t *offset, const char *s, size_t n)
{
ncat_assert(*offset <= *size);
if (n >= *size - *offset) {
*size += n + 1;
*buf = (char *) safe_realloc(*buf, *size);
}
memcpy(*buf + *offset, s, n);
*offset += n;
(*buf)[*offset] = '\0';
return n;
}
/* Append a '\0'-terminated string as with strbuf_append. */
int strbuf_append_str(char **buf, size_t *size, size_t *offset, const char *s)
{
return strbuf_append(buf, size, offset, s, strlen(s));
}
/* Do a sprintf at the given offset into a malloc-allocated buffer. Reallocates
the buffer and updates the variables to make room if necessary. */
int strbuf_sprintf(char **buf, size_t *size, size_t *offset, const char *fmt, ...)
{
va_list va;
int n;
ncat_assert(*offset <= *size);
if (*buf == NULL) {
*size = 1;
*buf = (char *) safe_malloc(*size);
}
for (;;) {
va_start(va, fmt);
n = Vsnprintf(*buf + *offset, *size - *offset, fmt, va);
va_end(va);
if (n < 0)
*size = MAX(*size, 1) * 2;
else if (n >= *size - *offset)
*size += n + 1;
else
break;
*buf = (char *) safe_realloc(*buf, *size);
}
*offset += n;
return n;
}
/* Return true if the given address is a local one. */
int addr_is_local(const union sockaddr_u *su)
{
struct addrinfo hints = { 0 }, *addrs, *addr;
char hostname[128];
/* Check loopback addresses. */
if (su->storage.ss_family == AF_INET) {
if ((ntohl(su->in.sin_addr.s_addr) & 0xFF000000UL) == 0x7F000000UL)
return 1;
if (ntohl(su->in.sin_addr.s_addr) == 0x00000000UL)
return 1;
}
#ifdef HAVE_IPV6
else if (su->storage.ss_family == AF_INET6) {
if (memcmp(&su->in6.sin6_addr, &in6addr_any, sizeof(su->in6.sin6_addr)) == 0
|| memcmp(&su->in6.sin6_addr, &in6addr_loopback, sizeof(su->in6.sin6_addr)) == 0)
return 1;
}
#endif
/* Check addresses assigned to the local host name. */
if (gethostname(hostname, sizeof(hostname)) == -1)
return 0;
hints.ai_family = su->storage.ss_family;
if (getaddrinfo(hostname, NULL, &hints, &addrs) != 0)
return 0;
for (addr = addrs; addr != NULL; addr = addr->ai_next) {
union sockaddr_u addr_su;
if (addr->ai_family != su->storage.ss_family)
continue;
if (addr->ai_addrlen > sizeof(addr_su)) {
bye("getaddrinfo returned oversized address (%lu > %lu)",
(unsigned long) addr->ai_addrlen, (unsigned long) sizeof(addr_su));
}
memcpy(&addr_su, addr->ai_addr, addr->ai_addrlen);
if (su->storage.ss_family == AF_INET) {
if (su->in.sin_addr.s_addr == addr_su.in.sin_addr.s_addr)
break;
} else if (su->storage.ss_family == AF_INET6) {
if (memcmp(&su->in6.sin6_addr, &addr_su.in6.sin6_addr, sizeof(su->in6.sin6_addr)) == 0)
break;
}
}
if (addr != NULL) {
freeaddrinfo(addrs);
return 1;
} else {
return 0;
}
}
/* Converts an IP address given in a sockaddr_u to an IPv4 or
IPv6 IP address string. Since a static buffer is returned, this is
not thread-safe and can only be used once in calls like printf()
*/
const char *inet_socktop(const union sockaddr_u *su)
{
static char buf[INET6_ADDRSTRLEN + 1];
void *addr;
if (su->storage.ss_family == AF_INET)
addr = (void *) &su->in.sin_addr;
#if HAVE_IPV6
else if (su->storage.ss_family == AF_INET6)
addr = (void *) &su->in6.sin6_addr;
#endif
else
addr = NULL;
if (inet_ntop(su->storage.ss_family, addr, buf, sizeof(buf)) == NULL) {
bye("Failed to convert address to presentation format! Error: %s.",
strerror(socket_errno()));
}
return buf;
}
/* Returns the port number in HOST BYTE ORDER based on the su's family */
unsigned short inet_port(const union sockaddr_u *su)
{
if (su->storage.ss_family == AF_INET)
return ntohs(su->in.sin_port);
#if HAVE_IPV6
else if (su->storage.ss_family == AF_INET6)
return ntohs(su->in6.sin6_port);
#endif
bye("Invalid address family passed to inet_port().");
return 0;
}
/* Return a listening socket after setting various characteristics on it.
Returns -1 on error. */
int do_listen(int type, int proto, const union sockaddr_u *srcaddr_u)
{
int sock = 0, option_on = 1;
size_t sa_len;
if (type != SOCK_STREAM && type != SOCK_DGRAM)
return -1;
/* We need a socket that can be inherited by child processes in
ncat_exec_win.c, for --exec and --sh-exec. inheritable_socket is from
nbase. */
sock = inheritable_socket(srcaddr_u->storage.ss_family, type, proto);
if (sock < 0)
return -1;
Setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &option_on, sizeof(int));
/* IPPROTO_IPV6 is defined in Visual C++ only when _WIN32_WINNT >= 0x501.
Nbase's nbase_winunix.h defines _WIN32_WINNT to a lower value for
compatibility with older versions of Windows. This code disables IPv6 sockets
that also receive IPv4 connections. This is the default on Windows anyway so
it doesn't make a difference.
http://support.microsoft.com/kb/950688
http://msdn.microsoft.com/en-us/library/bb513665
*/
#ifdef IPPROTO_IPV6
#ifdef IPV6_V6ONLY
if (srcaddr_u->storage.ss_family == AF_INET6) {
int set = 1;
/* Tell it to not try and bind to IPV4 */
if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &set, sizeof(set)) == -1)
die("Unable to set IPV6 socket to bind only to IPV6");
}
#endif
#endif
#ifdef HAVE_SYS_UN_H
if (srcaddr_u->storage.ss_family == AF_UNIX)
sa_len = SUN_LEN(&srcaddr_u->un);
else
#endif
#ifdef HAVE_SOCKADDR_SA_LEN
sa_len = srcaddr_u->sockaddr.sa_len;
#else
sa_len = sizeof(*srcaddr_u);
#endif
if (bind(sock, &srcaddr_u->sockaddr, sa_len) < 0) {
#ifdef HAVE_SYS_UN_H
if (srcaddr_u->storage.ss_family == AF_UNIX)
bye("bind to %s: %s.", srcaddr_u->un.sun_path,
socket_strerror(socket_errno()));
else
#endif
bye("bind to %s:%hu: %s.", inet_socktop(srcaddr_u),
inet_port(srcaddr_u), socket_strerror(socket_errno()));
}
if (type == SOCK_STREAM)
Listen(sock, BACKLOG);
if (o.verbose) {
#ifdef HAVE_SYS_UN_H
if (srcaddr_u->storage.ss_family == AF_UNIX)
loguser("Listening on %s\n", srcaddr_u->un.sun_path);
else
#endif
loguser("Listening on %s:%hu\n", inet_socktop(srcaddr_u), inet_port(srcaddr_u));
}
if (o.test)
logtest("LISTEN\n");
return sock;
}
int do_connect(int type)
{
int sock = 0;
if (type != SOCK_STREAM && type != SOCK_DGRAM)
return -1;
/* We need a socket that can be inherited by child processes in
ncat_exec_win.c, for --exec and --sh-exec. inheritable_socket is from
nbase. */
sock = inheritable_socket(targetss.storage.ss_family, type, 0);
if (srcaddr.storage.ss_family != AF_UNSPEC) {
size_t sa_len;
#ifdef HAVE_SOCKADDR_SA_LEN
sa_len = srcaddr.sockaddr.sa_len;
#else
sa_len = sizeof(srcaddr);
#endif
if (bind(sock, &srcaddr.sockaddr, sa_len) < 0) {
bye("bind to %s:%hu: %s.", inet_socktop(&srcaddr),
inet_port(&srcaddr), socket_strerror(socket_errno()));
}
}
if (sock != -1) {
if (connect(sock, &targetss.sockaddr, (int) targetsslen) != -1)
return sock;
else if (socket_errno() == EINPROGRESS || socket_errno() == EAGAIN)
return sock;
}
return -1;
}
unsigned char *buildsrcrte(struct in_addr dstaddr, struct in_addr routes[],
int numroutes, int ptr, size_t *len)
{
int x;
unsigned char *opts, *p;
*len = (numroutes + 1) * sizeof(struct in_addr) + 4;
if (numroutes > 8)
bye("Bad number of routes passed to buildsrcrte().");
opts = (unsigned char *) safe_malloc(*len);
p = opts;
zmem(opts, *len);
*p++ = 0x01; /* IPOPT_NOP, for alignment */
*p++ = 0x83; /* IPOPT_LSRR */
*p++ = (char) (*len - 1); /* subtract nop */
*p++ = (char) ptr;
for (x = 0; x < numroutes; x++) {
memcpy(p, &routes[x], sizeof(routes[x]));
p += sizeof(routes[x]);
}
memcpy(p, &dstaddr, sizeof(dstaddr));
return opts;
}
int allow_access(const union sockaddr_u *su)
{
/* A host not in the allow set is denied, but only if the --allow or
--allowfile option was given. */
if (o.allow && !addrset_contains(&o.allowset, &su->sockaddr))
return 0;
if (addrset_contains(&o.denyset, &su->sockaddr))
return 0;
return 1;
}
/*
* Fills the given timeval struct with proper
* values based on the given time in milliseconds.
* The pointer to timeval struct must NOT be NULL.
*/
void ms_to_timeval(struct timeval *tv, long ms)
{
tv->tv_sec = ms / 1000;
tv->tv_usec = (ms - (tv->tv_sec * 1000)) * 1000;
}
/*
* ugly code to maintain our list of fds so we can have proper fdmax for
* select(). really this should be generic list code, not this silly bit of
* stupidity. -sean
*/
/* add an fdinfo to our list */
int add_fdinfo(fd_list_t *fdl, struct fdinfo *s)
{
if (fdl->nfds >= fdl->maxfds)
return -1;
fdl->fds[fdl->nfds] = *s;
fdl->nfds++;
if (s->fd > fdl->fdmax)
fdl->fdmax = s->fd;
if (o.debug > 1)
logdebug("Added fd %d to list, nfds %d, maxfd %d\n", s->fd, fdl->nfds, fdl->fdmax);
return 0;
}
/* Add a descriptor to the list. Use this when you are only adding to the list
* for the side effect of increasing fdmax, and don't care about fdinfo
* members. */
int add_fd(fd_list_t *fdl, int fd)
{
struct fdinfo info = { 0 };
info.fd = fd;
return add_fdinfo(fdl, &info);
}
/* remove a descriptor from our list */
int rm_fd(fd_list_t *fdl, int fd)
{
int x = 0, last = fdl->nfds;
/* make sure we have a list */
if (last == 0)
bye("Program bug: Trying to remove fd from list with no fds.");
/* find the fd in the list */
for (x = 0; x < last; x++)
if (fdl->fds[x].fd == fd)
break;
/* make sure we found it */
if (x == last)
bye("Program bug: fd (%d) not on list.", fd);
/* remove it, does nothing if (last == 1) */
if (o.debug > 1)
logdebug("Swapping fd[%d] (%d) with fd[%d] (%d)\n",
x, fdl->fds[x].fd, last - 1, fdl->fds[last - 1].fd);
fdl->fds[x] = fdl->fds[last - 1];
fdl->nfds--;
/* was it the max */
if (fd == fdl->fdmax)
fdl->fdmax = get_maxfd(fdl);
if (o.debug > 1)
logdebug("Removed fd %d from list, nfds %d, maxfd %d\n", fd, fdl->nfds, fdl->fdmax);
return 0;
}
/* find the max descriptor in our list */
int get_maxfd(fd_list_t *fdl)
{
int x = 0, max = -1, nfds = fdl->nfds;
for (x = 0; x < nfds; x++)
if (fdl->fds[x].fd > max)
max = fdl->fds[x].fd;
return max;
}
struct fdinfo *get_fdinfo(const fd_list_t *fdl, int fd)
{
int x;
for (x = 0; x < fdl->nfds; x++)
if (fdl->fds[x].fd == fd)
return &fdl->fds[x];
return NULL;
}
void init_fdlist(fd_list_t *fdl, int maxfds)
{
fdl->fds = (struct fdinfo *) Calloc(maxfds, sizeof(struct fdinfo));
fdl->nfds = 0;
fdl->fdmax = -1;
fdl->maxfds = maxfds;
if (o.debug > 1)
logdebug("Initialized fdlist with %d maxfds\n", maxfds);
}
void free_fdlist(fd_list_t *fdl)
{
free(fdl->fds);
fdl->nfds = 0;
fdl->fdmax = -1;
}
/* If any changes need to be made to EOL sequences to comply with --crlf
* then dst will be populated with the modified src, len will be adjusted
* accordingly and the return will be non-zero.
*
* state is used to keep track of line endings that span more than one call to
* this function. On the first call, state should be a pointer to a int
* containing 0. Thereafter, keep passing the same pointer. Separate logical
* streams should use separate state pointers.
*
* Returns 0 if changes were not made - len and dst will remain untouched.
*/
int fix_line_endings(char *src, int *len, char **dst, int *state)
{
int fix_count;
int i, j;
int num_bytes = *len;
int prev_state = *state;
/* *state is true iff the last byte of the previous block was \r. */
if (num_bytes > 0)
*state = (src[num_bytes - 1] == '\r');
/* get count of \n without matching \r */
fix_count = 0;
for (i = 0; i < num_bytes; i++) {
if (src[i] == '\n' && ((i == 0) ? !prev_state : src[i - 1] != '\r'))
fix_count++;
}
if (fix_count <= 0)
return 0;
/* now insert matching \r */
*dst = (char *) safe_malloc(num_bytes + fix_count);
j = 0;
for (i = 0; i < num_bytes; i++) {
if (src[i] == '\n' && ((i == 0) ? !prev_state : src[i - 1] != '\r')) {
memcpy(*dst + j, "\r\n", 2);
j += 2;
} else {
memcpy(*dst + j, src + i, 1);
j++;
}
}
*len += fix_count;
return 1;
}
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