/*************************************************************************** * Buf.cc -- The Buf class is reponsible for I/O buffer manipulation * * and is based on the buffer code used in OpenSSH. * * * ***********************IMPORTANT NMAP LICENSE TERMS************************ * * * The Nmap Security Scanner is (C) 1996-2011 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 with the clarifications and exceptions described * * below. 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@insecure.com). Dozens of software vendors already * * license Nmap technology such as host discovery, port scanning, OS * * detection, and version detection. * * * * Note that the GPL places important restrictions on "derived works", yet * * it does not provide a detailed definition of that term. To avoid * * misunderstandings, we consider an application to constitute a * * "derivative work" for the purpose of this license if it does any of the * * following: * * o Integrates source code from Nmap * * o Reads or includes Nmap copyrighted data files, such as * * nmap-os-db or nmap-service-probes. * * o Executes Nmap and parses the results (as opposed to typical shell or * * execution-menu apps, which simply display raw Nmap output and so are * * not derivative works.) * * o Integrates/includes/aggregates Nmap into a proprietary executable * * installer, such as those produced by InstallShield. * * o Links to a library or executes a program that does any of the above * * * * The term "Nmap" should be taken to also include any portions or derived * * works of Nmap. This list is not exclusive, but is meant to clarify our * * interpretation of derived works with some common examples. Our * * interpretation applies only to Nmap--we don't speak for other people's * * GPL works. * * * * If you have any questions about the GPL licensing restrictions on using * * Nmap in non-GPL works, we would be 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 as well as helping to * * fund the continued development of Nmap technology. Please email * * sales@insecure.com for further information. * * * * As a 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. You must obey the GNU GPL in all * * respects for all of the code used other than OpenSSL. If you modify * * this file, you may extend this exception to your version of the file, * * but you are not obligated to do so. * * * * If you received these files with a written license agreement or * * contract stating terms other than the terms above, then that * * alternative license agreement takes precedence over these comments. * * * * 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 nmap-dev@insecure.org for possible incorporation into the main * * distribution. By sending these changes to Fyodor or one of the * * Insecure.Org development mailing lists, it is assumed 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 GNU * * General Public License v2.0 for more details at * * http://www.gnu.org/licenses/gpl-2.0.html , or in the COPYING file * * included with Nmap. * * * ***************************************************************************/ #include "Buf.h" Buf::Buf() { const u_int len = DEFAULT_BUF_SIZE; alloc = 0; buf = (u_char *)safe_malloc(len); alloc = len; offset = 0; end = 0; } /* Frees any memory used for the buffer. */ Buf::~Buf() { if (alloc > 0) { free(buf); buf = NULL; } } /* * Clears any data from the buffer, making it empty. This does not actually * zero the memory. */ void Buf::clear(void) { offset = 0; end = 0; } /* * Similar to way snprintf works, but data get saved inside the buffer. * Warning: data won't get null terminated * the len argument is the real length of the _actual_ data */ void Buf::snprintf(u_int len, const void *fmt, ...) { void *p; va_list ap; /* Since vsnprintf always null terminates the data, we * allocate one extra byte for the trailing '\0' and then * drop it by decreasing 'end' by 1 */ p = append_space(len + 1); va_start(ap, fmt); vsnprintf((char *)p, len + 1, (char *)fmt, ap); va_end(ap); end--; //memcpy(p, data, len); } /* Appends data to the buffer, expanding it if necessary. */ void Buf::append(const void *data, u_int len) { void *p; p = append_space(len); memcpy(p, data, len); } /* * Appends space to the buffer, expanding the buffer if necessary. This does * not actually copy the data into the buffer, but instead returns a pointer * to the allocated region. */ void * Buf::append_space(u_int len) { u_int newlen; void *p; if (len > BUFFER_MAX_CHUNK) fatal("%s: len %u not supported", __func__, len); /* If the buffer is empty, start using it from the beginning. */ if (offset == end) { offset = 0; end = 0; } restart: /* If there is enough space to store all data, store it now. */ if (end + len < alloc) { p = buf + end; end += len; return p; } /* Compact data back to the start of the buffer if necessary */ if (compact()) goto restart; /* Increase the size of the buffer and retry. */ newlen = roundup(alloc + len, BUFFER_ALLOCSZ); if (newlen > BUFFER_MAX_LEN) fatal("%s: alloc %u not supported", __func__, newlen); buf = (u_char *)safe_realloc(buf, newlen); alloc = newlen; goto restart; /* NOTREACHED */ } /* * Check whether an allocation of 'len' will fit in the buffer * This must follow the same math as buffer_append_space */ int Buf::check_alloc(u_int len) { if (offset == end) { offset = 0; end = 0; } restart: if (end + len < alloc) return (1); if (compact()) goto restart; if (roundup(alloc + len, BUFFER_ALLOCSZ) <= BUFFER_MAX_LEN) return (1); return (0); } /* Returns the number of bytes of data in the buffer. */ u_int Buf::get_len(void) { return end - offset; } /* Gets data from the beginning of the buffer. */ int Buf::get_data(void *dst, u_int len) { if (len > end - offset) { error("%s: trying to get more bytes %d than in buffer %d", __func__, len, end - offset); return (-1); } /* If dst is NULL then don't copy anything */ if (dst) memcpy(dst, buf + offset, len); offset += len; return (0); } int Buf::compact(void) { /* * If the buffer is quite empty, but all data is at the end, move the * data to the beginning. */ if (offset > MIN(alloc, BUFFER_MAX_CHUNK)) { memmove(buf, buf + offset, end - offset); end -= offset; offset = 0; return (1); } return (0); } /* Returns a pointer to the first used byte in the buffer. */ void * Buf::get_dataptr(void) { return buf + offset; } /* Dumps the contents of the buffer to stderr. */ void Buf::data_dump(void) { u_int i; u_char *ucp = buf; for (i = offset; i < end; i++) { fprintf(stderr, "%02x", ucp[i]); if ((i-offset)%16==15) fprintf(stderr, "\r\n"); else if ((i-offset)%2==1) fprintf(stderr, " "); } fprintf(stderr, "\r\n"); } /* Consumes the given number of bytes from the beginning of the buffer. */ #if 0 int buffer_consume_ret(Buffer *buffer, u_int bytes) { if (bytes > buffer->end - buffer->offset) { error("buffer_consume_ret: trying to get more bytes than in buffer"); return (-1); } buffer->offset += bytes; return (0); } void buffer_consume(Buffer *buffer, u_int bytes) { if (buffer_consume_ret(buffer, bytes) == -1) fatal("buffer_consume: buffer error"); } /* Consumes the given number of bytes from the end of the buffer. */ int buffer_consume_end_ret(Buffer *buffer, u_int bytes) { if (bytes > buffer->end - buffer->offset) return (-1); buffer->end -= bytes; return (0); } void buffer_consume_end(Buffer *buffer, u_int bytes) { if (buffer_consume_end_ret(buffer, bytes) == -1) fatal("buffer_consume_end: trying to get more bytes than in buffer"); } #endif