2 * Platform-independent routines shared between all PuTTY programs.
\r
14 * Parse a string block size specification. This is approximately a
\r
15 * subset of the block size specs supported by GNU fileutils:
\r
16 * "nk" = n kilobytes
\r
17 * "nM" = n megabytes
\r
18 * "nG" = n gigabytes
\r
19 * All numbers are decimal, and suffixes refer to powers of two.
\r
22 unsigned long parse_blocksize(const char *bs)
\r
25 unsigned long r = strtoul(bs, &suf, 10);
\r
27 while (*suf && isspace((unsigned char)*suf)) suf++;
\r
33 r *= 1024ul * 1024ul;
\r
36 r *= 1024ul * 1024ul * 1024ul;
\r
47 * Parse a ^C style character specification.
\r
48 * Returns NULL in `next' if we didn't recognise it as a control character,
\r
49 * in which case `c' should be ignored.
\r
50 * The precise current parsing is an oddity inherited from the terminal
\r
51 * answerback-string parsing code. All sequences start with ^; all except
\r
52 * ^<123> are two characters. The ones that are worth keeping are probably:
\r
56 * <num> specified by number (decimal, 0octal, 0xHEX)
\r
59 char ctrlparse(char *s, char **next)
\r
68 } else if (*s == '<') {
\r
70 c = (char)strtol(s, next, 0);
\r
71 if ((*next == s) || (**next != '>')) {
\r
76 } else if (*s >= 'a' && *s <= 'z') {
\r
77 c = (*s - ('a' - 1));
\r
79 } else if ((*s >= '@' && *s <= '_') || *s == '?' || (*s & 0x80)) {
\r
82 } else if (*s == '~') {
\r
90 prompts_t *new_prompts(void *frontend)
\r
92 prompts_t *p = snew(prompts_t);
\r
95 p->frontend = frontend;
\r
97 p->to_server = TRUE; /* to be on the safe side */
\r
98 p->name = p->instruction = NULL;
\r
99 p->name_reqd = p->instr_reqd = FALSE;
\r
102 void add_prompt(prompts_t *p, char *promptstr, int echo)
\r
104 prompt_t *pr = snew(prompt_t);
\r
105 pr->prompt = promptstr;
\r
108 pr->resultsize = 0;
\r
110 p->prompts = sresize(p->prompts, p->n_prompts, prompt_t *);
\r
111 p->prompts[p->n_prompts-1] = pr;
\r
113 void prompt_ensure_result_size(prompt_t *pr, int newlen)
\r
115 if ((int)pr->resultsize < newlen) {
\r
117 newlen = newlen * 5 / 4 + 512; /* avoid too many small allocs */
\r
120 * We don't use sresize / realloc here, because we will be
\r
121 * storing sensitive stuff like passwords in here, and we want
\r
122 * to make sure that the data doesn't get copied around in
\r
123 * memory without the old copy being destroyed.
\r
125 newbuf = snewn(newlen, char);
\r
126 memcpy(newbuf, pr->result, pr->resultsize);
\r
127 smemclr(pr->result, pr->resultsize);
\r
129 pr->result = newbuf;
\r
130 pr->resultsize = newlen;
\r
133 void prompt_set_result(prompt_t *pr, const char *newstr)
\r
135 prompt_ensure_result_size(pr, strlen(newstr) + 1);
\r
136 strcpy(pr->result, newstr);
\r
138 void free_prompts(prompts_t *p)
\r
141 for (i=0; i < p->n_prompts; i++) {
\r
142 prompt_t *pr = p->prompts[i];
\r
143 smemclr(pr->result, pr->resultsize); /* burn the evidence */
\r
150 sfree(p->instruction);
\r
154 /* ----------------------------------------------------------------------
\r
155 * String handling routines.
\r
158 char *dupstr(const char *s)
\r
162 int len = strlen(s);
\r
163 p = snewn(len + 1, char);
\r
169 /* Allocate the concatenation of N strings. Terminate arg list with NULL. */
\r
170 char *dupcat(const char *s1, ...)
\r
179 sn = va_arg(ap, char *);
\r
186 p = snewn(len + 1, char);
\r
192 sn = va_arg(ap, char *);
\r
203 void burnstr(char *string) /* sfree(str), only clear it first */
\r
206 smemclr(string, strlen(string));
\r
211 int toint(unsigned u)
\r
214 * Convert an unsigned to an int, without running into the
\r
215 * undefined behaviour which happens by the strict C standard if
\r
216 * the value overflows. You'd hope that sensible compilers would
\r
217 * do the sensible thing in response to a cast, but actually I
\r
218 * don't trust modern compilers not to do silly things like
\r
219 * assuming that _obviously_ you wouldn't have caused an overflow
\r
220 * and so they can elide an 'if (i < 0)' test immediately after
\r
223 * Sensible compilers ought of course to optimise this entire
\r
224 * function into 'just return the input value'!
\r
226 if (u <= (unsigned)INT_MAX)
\r
228 else if (u >= (unsigned)INT_MIN) /* wrap in cast _to_ unsigned is OK */
\r
229 return INT_MIN + (int)(u - (unsigned)INT_MIN);
\r
231 return INT_MIN; /* fallback; should never occur on binary machines */
\r
235 * Do an sprintf(), but into a custom-allocated buffer.
\r
237 * Currently I'm doing this via vsnprintf. This has worked so far,
\r
238 * but it's not good, because vsnprintf is not available on all
\r
239 * platforms. There's an ifdef to use `_vsnprintf', which seems
\r
240 * to be the local name for it on Windows. Other platforms may
\r
241 * lack it completely, in which case it'll be time to rewrite
\r
242 * this function in a totally different way.
\r
244 * The only `properly' portable solution I can think of is to
\r
245 * implement my own format string scanner, which figures out an
\r
246 * upper bound for the length of each formatting directive,
\r
247 * allocates the buffer as it goes along, and calls sprintf() to
\r
248 * actually process each directive. If I ever need to actually do
\r
249 * this, some caveats:
\r
251 * - It's very hard to find a reliable upper bound for
\r
252 * floating-point values. %f, in particular, when supplied with
\r
253 * a number near to the upper or lower limit of representable
\r
254 * numbers, could easily take several hundred characters. It's
\r
255 * probably feasible to predict this statically using the
\r
256 * constants in <float.h>, or even to predict it dynamically by
\r
257 * looking at the exponent of the specific float provided, but
\r
260 * - Don't forget to _check_, after calling sprintf, that it's
\r
261 * used at most the amount of space we had available.
\r
263 * - Fault any formatting directive we don't fully understand. The
\r
264 * aim here is to _guarantee_ that we never overflow the buffer,
\r
265 * because this is a security-critical function. If we see a
\r
266 * directive we don't know about, we should panic and die rather
\r
267 * than run any risk.
\r
269 char *dupprintf(const char *fmt, ...)
\r
274 ret = dupvprintf(fmt, ap);
\r
278 char *dupvprintf(const char *fmt, va_list ap)
\r
283 buf = snewn(512, char);
\r
288 #define vsnprintf _vsnprintf
\r
291 /* Use the `va_copy' macro mandated by C99, if present.
\r
292 * XXX some environments may have this as __va_copy() */
\r
295 len = vsnprintf(buf, size, fmt, aq);
\r
298 /* Ugh. No va_copy macro, so do something nasty.
\r
299 * Technically, you can't reuse a va_list like this: it is left
\r
300 * unspecified whether advancing a va_list pointer modifies its
\r
301 * value or something it points to, so on some platforms calling
\r
302 * vsnprintf twice on the same va_list might fail hideously
\r
303 * (indeed, it has been observed to).
\r
304 * XXX the autoconf manual suggests that using memcpy() will give
\r
305 * "maximum portability". */
\r
306 len = vsnprintf(buf, size, fmt, ap);
\r
308 if (len >= 0 && len < size) {
\r
309 /* This is the C99-specified criterion for snprintf to have
\r
310 * been completely successful. */
\r
312 } else if (len > 0) {
\r
313 /* This is the C99 error condition: the returned length is
\r
314 * the required buffer size not counting the NUL. */
\r
317 /* This is the pre-C99 glibc error condition: <0 means the
\r
318 * buffer wasn't big enough, so we enlarge it a bit and hope. */
\r
321 buf = sresize(buf, size, char);
\r
326 * Read an entire line of text from a file. Return a buffer
\r
327 * malloced to be as big as necessary (caller must free).
\r
329 char *fgetline(FILE *fp)
\r
331 char *ret = snewn(512, char);
\r
332 int size = 512, len = 0;
\r
333 while (fgets(ret + len, size - len, fp)) {
\r
334 len += strlen(ret + len);
\r
335 if (ret[len-1] == '\n')
\r
336 break; /* got a newline, we're done */
\r
338 ret = sresize(ret, size, char);
\r
340 if (len == 0) { /* first fgets returned NULL */
\r
348 /* ----------------------------------------------------------------------
\r
349 * Base64 encoding routine. This is required in public-key writing
\r
350 * but also in HTTP proxy handling, so it's centralised here.
\r
353 void base64_encode_atom(unsigned char *data, int n, char *out)
\r
355 static const char base64_chars[] =
\r
356 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
\r
360 word = data[0] << 16;
\r
362 word |= data[1] << 8;
\r
365 out[0] = base64_chars[(word >> 18) & 0x3F];
\r
366 out[1] = base64_chars[(word >> 12) & 0x3F];
\r
368 out[2] = base64_chars[(word >> 6) & 0x3F];
\r
372 out[3] = base64_chars[word & 0x3F];
\r
377 /* ----------------------------------------------------------------------
\r
378 * Generic routines to deal with send buffers: a linked list of
\r
379 * smallish blocks, with the operations
\r
381 * - add an arbitrary amount of data to the end of the list
\r
382 * - remove the first N bytes from the list
\r
383 * - return a (pointer,length) pair giving some initial data in
\r
384 * the list, suitable for passing to a send or write system
\r
386 * - retrieve a larger amount of initial data from the list
\r
387 * - return the current size of the buffer chain in bytes
\r
390 #define BUFFER_MIN_GRANULE 512
\r
392 struct bufchain_granule {
\r
393 struct bufchain_granule *next;
\r
394 char *bufpos, *bufend, *bufmax;
\r
397 void bufchain_init(bufchain *ch)
\r
399 ch->head = ch->tail = NULL;
\r
400 ch->buffersize = 0;
\r
403 void bufchain_clear(bufchain *ch)
\r
405 struct bufchain_granule *b;
\r
408 ch->head = ch->head->next;
\r
412 ch->buffersize = 0;
\r
415 int bufchain_size(bufchain *ch)
\r
417 return ch->buffersize;
\r
420 void bufchain_add(bufchain *ch, const void *data, int len)
\r
422 const char *buf = (const char *)data;
\r
424 if (len == 0) return;
\r
426 ch->buffersize += len;
\r
429 if (ch->tail && ch->tail->bufend < ch->tail->bufmax) {
\r
430 int copylen = min(len, ch->tail->bufmax - ch->tail->bufend);
\r
431 memcpy(ch->tail->bufend, buf, copylen);
\r
434 ch->tail->bufend += copylen;
\r
438 max(sizeof(struct bufchain_granule) + len, BUFFER_MIN_GRANULE);
\r
439 struct bufchain_granule *newbuf;
\r
440 newbuf = smalloc(grainlen);
\r
441 newbuf->bufpos = newbuf->bufend =
\r
442 (char *)newbuf + sizeof(struct bufchain_granule);
\r
443 newbuf->bufmax = (char *)newbuf + grainlen;
\r
444 newbuf->next = NULL;
\r
446 ch->tail->next = newbuf;
\r
454 void bufchain_consume(bufchain *ch, int len)
\r
456 struct bufchain_granule *tmp;
\r
458 assert(ch->buffersize >= len);
\r
461 assert(ch->head != NULL);
\r
462 if (remlen >= ch->head->bufend - ch->head->bufpos) {
\r
463 remlen = ch->head->bufend - ch->head->bufpos;
\r
465 ch->head = tmp->next;
\r
470 ch->head->bufpos += remlen;
\r
471 ch->buffersize -= remlen;
\r
476 void bufchain_prefix(bufchain *ch, void **data, int *len)
\r
478 *len = ch->head->bufend - ch->head->bufpos;
\r
479 *data = ch->head->bufpos;
\r
482 void bufchain_fetch(bufchain *ch, void *data, int len)
\r
484 struct bufchain_granule *tmp;
\r
485 char *data_c = (char *)data;
\r
489 assert(ch->buffersize >= len);
\r
493 assert(tmp != NULL);
\r
494 if (remlen >= tmp->bufend - tmp->bufpos)
\r
495 remlen = tmp->bufend - tmp->bufpos;
\r
496 memcpy(data_c, tmp->bufpos, remlen);
\r
504 /* ----------------------------------------------------------------------
\r
505 * My own versions of malloc, realloc and free. Because I want
\r
506 * malloc and realloc to bomb out and exit the program if they run
\r
507 * out of memory, realloc to reliably call malloc if passed a NULL
\r
508 * pointer, and free to reliably do nothing if passed a NULL
\r
509 * pointer. We can also put trace printouts in, if we need to; and
\r
510 * we can also replace the allocator with an ElectricFence-like
\r
515 void *minefield_c_malloc(size_t size);
\r
516 void minefield_c_free(void *p);
\r
517 void *minefield_c_realloc(void *p, size_t size);
\r
521 static FILE *fp = NULL;
\r
523 static char *mlog_file = NULL;
\r
524 static int mlog_line = 0;
\r
526 void mlog(char *file, int line)
\r
531 fp = fopen("putty_mem.log", "w");
\r
532 setvbuf(fp, NULL, _IONBF, BUFSIZ);
\r
535 fprintf(fp, "%s:%d: ", file, line);
\r
539 void *safemalloc(size_t n, size_t size)
\r
543 if (n > INT_MAX / size) {
\r
547 if (size == 0) size = 1;
\r
549 p = minefield_c_malloc(size);
\r
558 sprintf(str, "Out of memory! (%s:%d, size=%d)",
\r
559 mlog_file, mlog_line, size);
\r
560 fprintf(fp, "*** %s\n", str);
\r
563 strcpy(str, "Out of memory!");
\r
565 modalfatalbox(str);
\r
569 fprintf(fp, "malloc(%d) returns %p\n", size, p);
\r
574 void *saferealloc(void *ptr, size_t n, size_t size)
\r
578 if (n > INT_MAX / size) {
\r
584 p = minefield_c_malloc(size);
\r
590 p = minefield_c_realloc(ptr, size);
\r
592 p = realloc(ptr, size);
\r
600 sprintf(str, "Out of memory! (%s:%d, size=%d)",
\r
601 mlog_file, mlog_line, size);
\r
602 fprintf(fp, "*** %s\n", str);
\r
605 strcpy(str, "Out of memory!");
\r
607 modalfatalbox(str);
\r
611 fprintf(fp, "realloc(%p,%d) returns %p\n", ptr, size, p);
\r
616 void safefree(void *ptr)
\r
621 fprintf(fp, "free(%p)\n", ptr);
\r
624 minefield_c_free(ptr);
\r
631 fprintf(fp, "freeing null pointer - no action taken\n");
\r
635 /* ----------------------------------------------------------------------
\r
636 * Debugging routines.
\r
640 extern void dputs(char *); /* defined in per-platform *misc.c */
\r
642 void debug_printf(char *fmt, ...)
\r
648 buf = dupvprintf(fmt, ap);
\r
655 void debug_memdump(void *buf, int len, int L)
\r
658 unsigned char *p = buf;
\r
662 debug_printf("\t%d (0x%x) bytes:\n", len, len);
\r
663 delta = 15 & (unsigned long int) p;
\r
667 for (; 0 < len; p += 16, len -= 16) {
\r
670 debug_printf("%p: ", p);
\r
671 strcpy(foo, "................"); /* sixteen dots */
\r
672 for (i = 0; i < 16 && i < len; ++i) {
\r
673 if (&p[i] < (unsigned char *) buf) {
\r
674 dputs(" "); /* 3 spaces */
\r
677 debug_printf("%c%02.2x",
\r
678 &p[i] != (unsigned char *) buf
\r
679 && i % 4 ? '.' : ' ', p[i]
\r
681 if (p[i] >= ' ' && p[i] <= '~')
\r
682 foo[i] = (char) p[i];
\r
686 debug_printf("%*s%s\n", (16 - i) * 3 + 2, "", foo);
\r
690 #endif /* def DEBUG */
\r
693 * Determine whether or not a Conf represents a session which can
\r
694 * sensibly be launched right now.
\r
696 int conf_launchable(Conf *conf)
\r
698 if (conf_get_int(conf, CONF_protocol) == PROT_SERIAL)
\r
699 return conf_get_str(conf, CONF_serline)[0] != 0;
\r
701 return conf_get_str(conf, CONF_host)[0] != 0;
\r
704 char const *conf_dest(Conf *conf)
\r
706 if (conf_get_int(conf, CONF_protocol) == PROT_SERIAL)
\r
707 return conf_get_str(conf, CONF_serline);
\r
709 return conf_get_str(conf, CONF_host);
\r
712 #ifndef PLATFORM_HAS_SMEMCLR
\r
714 * Securely wipe memory.
\r
716 * The actual wiping is no different from what memset would do: the
\r
717 * point of 'securely' is to try to be sure over-clever compilers
\r
718 * won't optimise away memsets on variables that are about to be freed
\r
719 * or go out of scope. See
\r
720 * https://buildsecurityin.us-cert.gov/bsi-rules/home/g1/771-BSI.html
\r
722 * Some platforms (e.g. Windows) may provide their own version of this
\r
725 void smemclr(void *b, size_t n) {
\r
730 * Zero out the memory.
\r
735 * Perform a volatile access to the object, forcing the
\r
736 * compiler to admit that the previous memset was important.
\r
738 * This while loop should in practice run for zero iterations
\r
739 * (since we know we just zeroed the object out), but in
\r
740 * theory (as far as the compiler knows) it might range over
\r
741 * the whole object. (If we had just written, say, '*vp =
\r
742 * *vp;', a compiler could in principle have 'helpfully'
\r
743 * optimised the memset into only zeroing out the first byte.
\r
744 * This should be robust.)
\r