| /* |
| * Dropbear - a SSH2 server |
| * |
| * Copyright (c) 2002,2003 Matt Johnston |
| * All rights reserved. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| * SOFTWARE. |
| * |
| * strlcat() is copyright as follows: |
| * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com> |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, |
| * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY |
| * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL |
| * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ |
| |
| #include "includes.h" |
| #include "dbutil.h" |
| #include "buffer.h" |
| #include "session.h" |
| #include "atomicio.h" |
| |
| #define MAX_FMT 100 |
| |
| static void generic_dropbear_exit(int exitcode, const char* format, |
| va_list param); |
| static void generic_dropbear_log(int priority, const char* format, |
| va_list param); |
| |
| void (*_dropbear_exit)(int exitcode, const char* format, va_list param) |
| = generic_dropbear_exit; |
| void (*_dropbear_log)(int priority, const char* format, va_list param) |
| = generic_dropbear_log; |
| |
| #ifdef DEBUG_TRACE |
| int debug_trace = 0; |
| #endif |
| |
| #ifndef DISABLE_SYSLOG |
| void startsyslog() { |
| |
| openlog(PROGNAME, LOG_PID, LOG_AUTHPRIV); |
| |
| } |
| #endif /* DISABLE_SYSLOG */ |
| |
| /* the "format" string must be <= 100 characters */ |
| void dropbear_close(const char* format, ...) { |
| |
| va_list param; |
| |
| va_start(param, format); |
| _dropbear_exit(EXIT_SUCCESS, format, param); |
| va_end(param); |
| |
| } |
| |
| void dropbear_exit(const char* format, ...) { |
| |
| va_list param; |
| |
| va_start(param, format); |
| _dropbear_exit(EXIT_FAILURE, format, param); |
| va_end(param); |
| } |
| |
| static void generic_dropbear_exit(int exitcode, const char* format, |
| va_list param) { |
| |
| char fmtbuf[300]; |
| |
| snprintf(fmtbuf, sizeof(fmtbuf), "Exited: %s", format); |
| |
| _dropbear_log(LOG_INFO, fmtbuf, param); |
| |
| exit(exitcode); |
| } |
| |
| void fail_assert(const char* expr, const char* file, int line) { |
| dropbear_exit("failed assertion (%s:%d): `%s'", file, line, expr); |
| } |
| |
| static void generic_dropbear_log(int UNUSED(priority), const char* format, |
| va_list param) { |
| |
| char printbuf[1024]; |
| |
| vsnprintf(printbuf, sizeof(printbuf), format, param); |
| |
| fprintf(stderr, "%s\n", printbuf); |
| |
| } |
| |
| /* this is what can be called to write arbitrary log messages */ |
| void dropbear_log(int priority, const char* format, ...) { |
| |
| va_list param; |
| |
| va_start(param, format); |
| _dropbear_log(priority, format, param); |
| va_end(param); |
| } |
| |
| |
| #ifdef DEBUG_TRACE |
| void dropbear_trace(const char* format, ...) { |
| |
| va_list param; |
| |
| if (!debug_trace) { |
| return; |
| } |
| |
| va_start(param, format); |
| fprintf(stderr, "TRACE: "); |
| vfprintf(stderr, format, param); |
| fprintf(stderr, "\n"); |
| va_end(param); |
| } |
| #endif /* DEBUG_TRACE */ |
| |
| static void set_sock_priority(int sock) { |
| |
| int val; |
| |
| /* disable nagle */ |
| val = 1; |
| setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void*)&val, sizeof(val)); |
| |
| /* set the TOS bit. note that this will fail for ipv6, I can't find any |
| * equivalent. */ |
| #ifdef IPTOS_LOWDELAY |
| val = IPTOS_LOWDELAY; |
| setsockopt(sock, IPPROTO_IP, IP_TOS, (void*)&val, sizeof(val)); |
| #endif |
| |
| #ifdef SO_PRIORITY |
| /* linux specific, sets QoS class. |
| * 6 looks to be optimal for interactive traffic (see tc-prio(8) ). */ |
| val = 6; |
| setsockopt(sock, SOL_SOCKET, SO_PRIORITY, (void*) &val, sizeof(val)); |
| #endif |
| |
| } |
| |
| /* Listen on address:port. |
| * Special cases are address of "" listening on everything, |
| * and address of NULL listening on localhost only. |
| * Returns the number of sockets bound on success, or -1 on failure. On |
| * failure, if errstring wasn't NULL, it'll be a newly malloced error |
| * string.*/ |
| int dropbear_listen(const char* address, const char* port, |
| int *socks, unsigned int sockcount, char **errstring, int *maxfd) { |
| |
| struct addrinfo hints, *res = NULL, *res0 = NULL; |
| int err; |
| unsigned int nsock; |
| struct linger linger; |
| int val; |
| int sock; |
| |
| TRACE(("enter dropbear_listen")) |
| |
| memset(&hints, 0, sizeof(hints)); |
| hints.ai_family = AF_UNSPEC; /* TODO: let them flag v4 only etc */ |
| hints.ai_socktype = SOCK_STREAM; |
| |
| // for calling getaddrinfo: |
| // address == NULL and !AI_PASSIVE: local loopback |
| // address == NULL and AI_PASSIVE: all interfaces |
| // address != NULL: whatever the address says |
| if (!address) { |
| TRACE(("dropbear_listen: local loopback")) |
| } else { |
| if (address[0] == '\0') { |
| TRACE(("dropbear_listen: all interfaces")) |
| address = NULL; |
| } |
| hints.ai_flags = AI_PASSIVE; |
| } |
| err = getaddrinfo(address, port, &hints, &res0); |
| |
| if (err) { |
| if (errstring != NULL && *errstring == NULL) { |
| int len; |
| len = 20 + strlen(gai_strerror(err)); |
| *errstring = (char*)m_malloc(len); |
| snprintf(*errstring, len, "Error resolving: %s", gai_strerror(err)); |
| } |
| if (res0) { |
| freeaddrinfo(res0); |
| res0 = NULL; |
| } |
| TRACE(("leave dropbear_listen: failed resolving")) |
| return -1; |
| } |
| |
| |
| nsock = 0; |
| for (res = res0; res != NULL && nsock < sockcount; |
| res = res->ai_next) { |
| |
| /* Get a socket */ |
| socks[nsock] = socket(res->ai_family, res->ai_socktype, |
| res->ai_protocol); |
| |
| sock = socks[nsock]; /* For clarity */ |
| |
| if (sock < 0) { |
| err = errno; |
| TRACE(("socket() failed")) |
| continue; |
| } |
| |
| /* Various useful socket options */ |
| val = 1; |
| /* set to reuse, quick timeout */ |
| setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void*) &val, sizeof(val)); |
| linger.l_onoff = 1; |
| linger.l_linger = 5; |
| setsockopt(sock, SOL_SOCKET, SO_LINGER, (void*)&linger, sizeof(linger)); |
| |
| set_sock_priority(sock); |
| |
| if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) { |
| err = errno; |
| close(sock); |
| TRACE(("bind(%s) failed", port)) |
| continue; |
| } |
| |
| if (listen(sock, 20) < 0) { |
| err = errno; |
| close(sock); |
| TRACE(("listen() failed")) |
| continue; |
| } |
| |
| *maxfd = MAX(*maxfd, sock); |
| |
| nsock++; |
| } |
| |
| if (res0) { |
| freeaddrinfo(res0); |
| res0 = NULL; |
| } |
| |
| if (nsock == 0) { |
| if (errstring != NULL && *errstring == NULL) { |
| int len; |
| len = 20 + strlen(strerror(err)); |
| *errstring = (char*)m_malloc(len); |
| snprintf(*errstring, len, "Error listening: %s", strerror(err)); |
| TRACE(("leave dropbear_listen: failure, %s", strerror(err))) |
| return -1; |
| } |
| } |
| |
| TRACE(("leave dropbear_listen: success, %d socks bound", nsock)) |
| return nsock; |
| } |
| |
| /* Connect via TCP to a host. Connection will try ipv4 or ipv6, will |
| * return immediately if nonblocking is set. On failure, if errstring |
| * wasn't null, it will be a newly malloced error message */ |
| |
| /* TODO: maxfd */ |
| int connect_remote(const char* remotehost, const char* remoteport, |
| int nonblocking, char ** errstring) { |
| |
| struct addrinfo *res0 = NULL, *res = NULL, hints; |
| int sock; |
| int err; |
| |
| TRACE(("enter connect_remote")) |
| |
| if (errstring != NULL) { |
| *errstring = NULL; |
| } |
| |
| memset(&hints, 0, sizeof(hints)); |
| hints.ai_socktype = SOCK_STREAM; |
| hints.ai_family = PF_UNSPEC; |
| |
| err = getaddrinfo(remotehost, remoteport, &hints, &res0); |
| if (err) { |
| if (errstring != NULL && *errstring == NULL) { |
| int len; |
| len = 20 + strlen(gai_strerror(err)); |
| *errstring = (char*)m_malloc(len); |
| snprintf(*errstring, len, "Error resolving: %s", gai_strerror(err)); |
| } |
| TRACE(("Error resolving: %s", gai_strerror(err))) |
| return -1; |
| } |
| |
| sock = -1; |
| err = EADDRNOTAVAIL; |
| for (res = res0; res; res = res->ai_next) { |
| |
| sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol); |
| if (sock < 0) { |
| err = errno; |
| continue; |
| } |
| |
| if (nonblocking) { |
| if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0) { |
| close(sock); |
| sock = -1; |
| if (errstring != NULL && *errstring == NULL) { |
| *errstring = m_strdup("Failed non-blocking"); |
| } |
| TRACE(("Failed non-blocking: %s", strerror(errno))) |
| continue; |
| } |
| } |
| |
| if (connect(sock, res->ai_addr, res->ai_addrlen) < 0) { |
| if (errno == EINPROGRESS && nonblocking) { |
| TRACE(("Connect in progress")) |
| break; |
| } else { |
| err = errno; |
| close(sock); |
| sock = -1; |
| continue; |
| } |
| } |
| |
| break; /* Success */ |
| } |
| |
| if (sock < 0 && !(errno == EINPROGRESS && nonblocking)) { |
| /* Failed */ |
| if (errstring != NULL && *errstring == NULL) { |
| int len; |
| len = 20 + strlen(strerror(err)); |
| *errstring = (char*)m_malloc(len); |
| snprintf(*errstring, len, "Error connecting: %s", strerror(err)); |
| } |
| TRACE(("Error connecting: %s", strerror(err))) |
| } else { |
| /* Success */ |
| set_sock_priority(sock); |
| } |
| |
| freeaddrinfo(res0); |
| if (sock > 0 && errstring != NULL && *errstring != NULL) { |
| m_free(*errstring); |
| } |
| |
| TRACE(("leave connect_remote: sock %d\n", sock)) |
| return sock; |
| } |
| |
| /* Return a string representation of the socket address passed. The return |
| * value is allocated with malloc() */ |
| unsigned char * getaddrstring(struct sockaddr_storage* addr, int withport) { |
| |
| char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV]; |
| char *retstring = NULL; |
| int ret; |
| unsigned int len; |
| |
| len = sizeof(struct sockaddr_storage); |
| /* Some platforms such as Solaris 8 require that len is the length |
| * of the specific structure. */ |
| if (addr->ss_family == AF_INET) { |
| len = sizeof(struct sockaddr_in); |
| } |
| #ifdef AF_INET6 |
| if (addr->ss_family == AF_INET6) { |
| len = sizeof(struct sockaddr_in6); |
| } |
| #endif |
| |
| ret = getnameinfo((struct sockaddr*)addr, len, hbuf, sizeof(hbuf), |
| sbuf, sizeof(sbuf), NI_NUMERICSERV | NI_NUMERICHOST); |
| |
| if (ret != 0) { |
| /* This is a fairly bad failure - it'll fallback to IP if it |
| * just can't resolve */ |
| dropbear_exit("failed lookup (%d, %d)", ret, errno); |
| } |
| |
| if (withport) { |
| len = strlen(hbuf) + 2 + strlen(sbuf); |
| retstring = (char*)m_malloc(len); |
| snprintf(retstring, len, "%s:%s", hbuf, sbuf); |
| } else { |
| retstring = m_strdup(hbuf); |
| } |
| |
| return retstring; |
| |
| } |
| |
| /* Get the hostname corresponding to the address addr. On failure, the IP |
| * address is returned. The return value is allocated with strdup() */ |
| char* getaddrhostname(struct sockaddr_storage * addr) { |
| |
| char hbuf[NI_MAXHOST]; |
| char sbuf[NI_MAXSERV]; |
| int ret; |
| unsigned int len; |
| #ifdef DO_HOST_LOOKUP |
| const int flags = NI_NUMERICSERV; |
| #else |
| const int flags = NI_NUMERICHOST | NI_NUMERICSERV; |
| #endif |
| |
| len = sizeof(struct sockaddr_storage); |
| /* Some platforms such as Solaris 8 require that len is the length |
| * of the specific structure. */ |
| if (addr->ss_family == AF_INET) { |
| len = sizeof(struct sockaddr_in); |
| } |
| #ifdef AF_INET6 |
| if (addr->ss_family == AF_INET6) { |
| len = sizeof(struct sockaddr_in6); |
| } |
| #endif |
| |
| |
| ret = getnameinfo((struct sockaddr*)addr, len, hbuf, sizeof(hbuf), |
| sbuf, sizeof(sbuf), flags); |
| |
| if (ret != 0) { |
| /* On some systems (Darwin does it) we get EINTR from getnameinfo |
| * somehow. Eew. So we'll just return the IP, since that doesn't seem |
| * to exhibit that behaviour. */ |
| return getaddrstring(addr, 0); |
| } |
| |
| return m_strdup(hbuf); |
| } |
| |
| #ifdef DEBUG_TRACE |
| void printhex(const char * label, const unsigned char * buf, int len) { |
| |
| int i; |
| |
| fprintf(stderr, "%s\n", label); |
| for (i = 0; i < len; i++) { |
| fprintf(stderr, "%02x", buf[i]); |
| if (i % 16 == 15) { |
| fprintf(stderr, "\n"); |
| } |
| else if (i % 2 == 1) { |
| fprintf(stderr, " "); |
| } |
| } |
| fprintf(stderr, "\n"); |
| } |
| #endif |
| |
| /* Strip all control characters from text (a null-terminated string), except |
| * for '\n', '\r' and '\t'. |
| * The result returned is a newly allocated string, this must be free()d after |
| * use */ |
| char * stripcontrol(const char * text) { |
| |
| char * ret; |
| int len, pos; |
| int i; |
| |
| len = strlen(text); |
| ret = m_malloc(len+1); |
| |
| pos = 0; |
| for (i = 0; i < len; i++) { |
| if ((text[i] <= '~' && text[i] >= ' ') /* normal printable range */ |
| || text[i] == '\n' || text[i] == '\r' || text[i] == '\t') { |
| ret[pos] = text[i]; |
| pos++; |
| } |
| } |
| ret[pos] = 0x0; |
| return ret; |
| } |
| |
| |
| /* reads the contents of filename into the buffer buf, from the current |
| * position, either to the end of the file, or the buffer being full. |
| * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */ |
| int buf_readfile(buffer* buf, const char* filename) { |
| |
| int fd; |
| int len; |
| int maxlen; |
| |
| fd = open(filename, O_RDONLY); |
| |
| if (fd < 0) { |
| close(fd); |
| return DROPBEAR_FAILURE; |
| } |
| |
| do { |
| maxlen = buf->size - buf->pos; |
| len = read(fd, buf_getwriteptr(buf, maxlen), |
| maxlen); |
| buf_incrwritepos(buf, len); |
| } while (len < maxlen && len > 0); |
| |
| close(fd); |
| return DROPBEAR_SUCCESS; |
| } |
| |
| /* get a line from the file into buffer in the style expected for an |
| * authkeys file. |
| * Will return DROPBEAR_SUCCESS if data is read, or DROPBEAR_FAILURE on EOF.*/ |
| /* Only used for ~/.ssh/known_hosts and ~/.ssh/authorized_keys */ |
| #if defined(DROPBEAR_CLIENT) || defined(ENABLE_SVR_PUBKEY_AUTH) |
| int buf_getline(buffer * line, FILE * authfile) { |
| |
| int c = EOF; |
| |
| TRACE(("enter buf_getline")) |
| |
| buf_setpos(line, 0); |
| buf_setlen(line, 0); |
| |
| while (line->pos < line->size) { |
| |
| c = fgetc(authfile); /*getc() is weird with some uClibc systems*/ |
| if (c == EOF || c == '\n' || c == '\r') { |
| goto out; |
| } |
| |
| buf_putbyte(line, (unsigned char)c); |
| } |
| |
| TRACE(("leave getauthline: line too long")) |
| /* We return success, but the line length will be zeroed - ie we just |
| * ignore that line */ |
| buf_setlen(line, 0); |
| |
| out: |
| |
| |
| /* if we didn't read anything before EOF or error, exit */ |
| if (c == EOF && line->pos == 0) { |
| TRACE(("leave buf_getline: failure")) |
| return DROPBEAR_FAILURE; |
| } else { |
| TRACE(("leave buf_getline: success")) |
| buf_setpos(line, 0); |
| return DROPBEAR_SUCCESS; |
| } |
| |
| } |
| #endif |
| |
| /* loop until the socket is closed (in case of EINTR) or |
| * we get and error. |
| * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */ |
| int m_close(int fd) { |
| |
| int val; |
| do { |
| val = close(fd); |
| } while (val < 0 && errno == EINTR); |
| |
| if (val == 0 || errno == EBADF) { |
| return DROPBEAR_SUCCESS; |
| } else { |
| return DROPBEAR_FAILURE; |
| } |
| } |
| |
| void * m_malloc(size_t size) { |
| |
| void* ret; |
| |
| if (size == 0) { |
| dropbear_exit("m_malloc failed"); |
| } |
| ret = calloc(1, size); |
| if (ret == NULL) { |
| dropbear_exit("m_malloc failed"); |
| } |
| return ret; |
| |
| } |
| |
| void * m_strdup(const char * str) { |
| char* ret; |
| |
| ret = strdup(str); |
| if (ret == NULL) { |
| dropbear_exit("m_strdup failed"); |
| } |
| return ret; |
| } |
| |
| void __m_free(void* ptr) { |
| if (ptr != NULL) { |
| free(ptr); |
| } |
| } |
| |
| void * m_realloc(void* ptr, size_t size) { |
| |
| void *ret; |
| |
| if (size == 0) { |
| dropbear_exit("m_realloc failed"); |
| } |
| ret = realloc(ptr, size); |
| if (ret == NULL) { |
| dropbear_exit("m_realloc failed"); |
| } |
| return ret; |
| } |
| |
| /* Clear the data, based on the method in David Wheeler's |
| * "Secure Programming for Linux and Unix HOWTO" */ |
| /* Beware of calling this from within dbutil.c - things might get |
| * optimised away */ |
| void m_burn(void *data, unsigned int len) { |
| volatile char *p = data; |
| |
| if (data == NULL) |
| return; |
| while (len--) { |
| *p++ = 0x66; |
| } |
| } |
| |
| |
| void setnonblocking(int fd) { |
| |
| TRACE(("setnonblocking: %d", fd)) |
| |
| if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) { |
| if (errno == ENODEV) { |
| /* Some devices (like /dev/null redirected in) |
| * can't be set to non-blocking */ |
| TRACE(("ignoring ENODEV for setnonblocking")) |
| } else { |
| dropbear_exit("Couldn't set nonblocking"); |
| } |
| } |
| TRACE(("leave setnonblocking")) |
| } |