+/*
+ * Platform-independent routines shared between all PuTTY programs.
+ */
+
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
+#include <limits.h>
#include <ctype.h>
#include <assert.h>
#include "putty.h"
+/*
+ * Parse a string block size specification. This is approximately a
+ * subset of the block size specs supported by GNU fileutils:
+ * "nk" = n kilobytes
+ * "nM" = n megabytes
+ * "nG" = n gigabytes
+ * All numbers are decimal, and suffixes refer to powers of two.
+ * Case-insensitive.
+ */
+unsigned long parse_blocksize(const char *bs)
+{
+ char *suf;
+ unsigned long r = strtoul(bs, &suf, 10);
+ if (*suf != '\0') {
+ while (*suf && isspace((unsigned char)*suf)) suf++;
+ switch (*suf) {
+ case 'k': case 'K':
+ r *= 1024ul;
+ break;
+ case 'm': case 'M':
+ r *= 1024ul * 1024ul;
+ break;
+ case 'g': case 'G':
+ r *= 1024ul * 1024ul * 1024ul;
+ break;
+ case '\0':
+ default:
+ break;
+ }
+ }
+ return r;
+}
+
+/*
+ * Parse a ^C style character specification.
+ * Returns NULL in `next' if we didn't recognise it as a control character,
+ * in which case `c' should be ignored.
+ * The precise current parsing is an oddity inherited from the terminal
+ * answerback-string parsing code. All sequences start with ^; all except
+ * ^<123> are two characters. The ones that are worth keeping are probably:
+ * ^? 127
+ * ^@A-Z[\]^_ 0-31
+ * a-z 1-26
+ * <num> specified by number (decimal, 0octal, 0xHEX)
+ * ~ ^ escape
+ */
+char ctrlparse(char *s, char **next)
+{
+ char c = 0;
+ if (*s != '^') {
+ *next = NULL;
+ } else {
+ s++;
+ if (*s == '\0') {
+ *next = NULL;
+ } else if (*s == '<') {
+ s++;
+ c = (char)strtol(s, next, 0);
+ if ((*next == s) || (**next != '>')) {
+ c = 0;
+ *next = NULL;
+ } else
+ (*next)++;
+ } else if (*s >= 'a' && *s <= 'z') {
+ c = (*s - ('a' - 1));
+ *next = s+1;
+ } else if ((*s >= '@' && *s <= '_') || *s == '?' || (*s & 0x80)) {
+ c = ('@' ^ *s);
+ *next = s+1;
+ } else if (*s == '~') {
+ c = '^';
+ *next = s+1;
+ }
+ }
+ return c;
+}
+
+prompts_t *new_prompts(void *frontend)
+{
+ prompts_t *p = snew(prompts_t);
+ p->prompts = NULL;
+ p->n_prompts = 0;
+ p->frontend = frontend;
+ p->data = NULL;
+ p->to_server = TRUE; /* to be on the safe side */
+ p->name = p->instruction = NULL;
+ p->name_reqd = p->instr_reqd = FALSE;
+ return p;
+}
+void add_prompt(prompts_t *p, char *promptstr, int echo)
+{
+ prompt_t *pr = snew(prompt_t);
+ pr->prompt = promptstr;
+ pr->echo = echo;
+ pr->result = NULL;
+ pr->resultsize = 0;
+ p->n_prompts++;
+ p->prompts = sresize(p->prompts, p->n_prompts, prompt_t *);
+ p->prompts[p->n_prompts-1] = pr;
+}
+void prompt_ensure_result_size(prompt_t *pr, int newlen)
+{
+ if ((int)pr->resultsize < newlen) {
+ char *newbuf;
+ newlen = newlen * 5 / 4 + 512; /* avoid too many small allocs */
+
+ /*
+ * We don't use sresize / realloc here, because we will be
+ * storing sensitive stuff like passwords in here, and we want
+ * to make sure that the data doesn't get copied around in
+ * memory without the old copy being destroyed.
+ */
+ newbuf = snewn(newlen, char);
+ memcpy(newbuf, pr->result, pr->resultsize);
+ smemclr(pr->result, pr->resultsize);
+ sfree(pr->result);
+ pr->result = newbuf;
+ pr->resultsize = newlen;
+ }
+}
+void prompt_set_result(prompt_t *pr, const char *newstr)
+{
+ prompt_ensure_result_size(pr, strlen(newstr) + 1);
+ strcpy(pr->result, newstr);
+}
+void free_prompts(prompts_t *p)
+{
+ size_t i;
+ for (i=0; i < p->n_prompts; i++) {
+ prompt_t *pr = p->prompts[i];
+ smemclr(pr->result, pr->resultsize); /* burn the evidence */
+ sfree(pr->result);
+ sfree(pr->prompt);
+ sfree(pr);
+ }
+ sfree(p->prompts);
+ sfree(p->name);
+ sfree(p->instruction);
+ sfree(p);
+}
+
/* ----------------------------------------------------------------------
* String handling routines.
*/
return p;
}
+void burnstr(char *string) /* sfree(str), only clear it first */
+{
+ if (string) {
+ smemclr(string, strlen(string));
+ sfree(string);
+ }
+}
+
+int toint(unsigned u)
+{
+ /*
+ * Convert an unsigned to an int, without running into the
+ * undefined behaviour which happens by the strict C standard if
+ * the value overflows. You'd hope that sensible compilers would
+ * do the sensible thing in response to a cast, but actually I
+ * don't trust modern compilers not to do silly things like
+ * assuming that _obviously_ you wouldn't have caused an overflow
+ * and so they can elide an 'if (i < 0)' test immediately after
+ * the cast.
+ *
+ * Sensible compilers ought of course to optimise this entire
+ * function into 'just return the input value'!
+ */
+ if (u <= (unsigned)INT_MAX)
+ return (int)u;
+ else if (u >= (unsigned)INT_MIN) /* wrap in cast _to_ unsigned is OK */
+ return INT_MIN + (int)(u - (unsigned)INT_MIN);
+ else
+ return INT_MIN; /* fallback; should never occur on binary machines */
+}
+
/*
* Do an sprintf(), but into a custom-allocated buffer.
*
- * Irritatingly, we don't seem to be able to do this portably using
- * vsnprintf(), because there appear to be issues with re-using the
- * same va_list for two calls, and the excellent C99 va_copy is not
- * yet widespread. Bah. Instead I'm going to do a horrid, horrid
- * hack, in which I trawl the format string myself, work out the
- * maximum length of each format component, and resize the buffer
- * before printing it.
+ * Currently I'm doing this via vsnprintf. This has worked so far,
+ * but it's not good, because vsnprintf is not available on all
+ * platforms. There's an ifdef to use `_vsnprintf', which seems
+ * to be the local name for it on Windows. Other platforms may
+ * lack it completely, in which case it'll be time to rewrite
+ * this function in a totally different way.
+ *
+ * The only `properly' portable solution I can think of is to
+ * implement my own format string scanner, which figures out an
+ * upper bound for the length of each formatting directive,
+ * allocates the buffer as it goes along, and calls sprintf() to
+ * actually process each directive. If I ever need to actually do
+ * this, some caveats:
+ *
+ * - It's very hard to find a reliable upper bound for
+ * floating-point values. %f, in particular, when supplied with
+ * a number near to the upper or lower limit of representable
+ * numbers, could easily take several hundred characters. It's
+ * probably feasible to predict this statically using the
+ * constants in <float.h>, or even to predict it dynamically by
+ * looking at the exponent of the specific float provided, but
+ * it won't be fun.
+ *
+ * - Don't forget to _check_, after calling sprintf, that it's
+ * used at most the amount of space we had available.
+ *
+ * - Fault any formatting directive we don't fully understand. The
+ * aim here is to _guarantee_ that we never overflow the buffer,
+ * because this is a security-critical function. If we see a
+ * directive we don't know about, we should panic and die rather
+ * than run any risk.
*/
char *dupprintf(const char *fmt, ...)
{
#ifdef _WINDOWS
#define vsnprintf _vsnprintf
#endif
+#ifdef va_copy
+ /* Use the `va_copy' macro mandated by C99, if present.
+ * XXX some environments may have this as __va_copy() */
+ va_list aq;
+ va_copy(aq, ap);
+ len = vsnprintf(buf, size, fmt, aq);
+ va_end(aq);
+#else
+ /* Ugh. No va_copy macro, so do something nasty.
+ * Technically, you can't reuse a va_list like this: it is left
+ * unspecified whether advancing a va_list pointer modifies its
+ * value or something it points to, so on some platforms calling
+ * vsnprintf twice on the same va_list might fail hideously
+ * (indeed, it has been observed to).
+ * XXX the autoconf manual suggests that using memcpy() will give
+ * "maximum portability". */
len = vsnprintf(buf, size, fmt, ap);
+#endif
if (len >= 0 && len < size) {
/* This is the C99-specified criterion for snprintf to have
* been completely successful. */
}
}
+/*
+ * Read an entire line of text from a file. Return a buffer
+ * malloced to be as big as necessary (caller must free).
+ */
+char *fgetline(FILE *fp)
+{
+ char *ret = snewn(512, char);
+ int size = 512, len = 0;
+ while (fgets(ret + len, size - len, fp)) {
+ len += strlen(ret + len);
+ if (ret[len-1] == '\n')
+ break; /* got a newline, we're done */
+ size = len + 512;
+ ret = sresize(ret, size, char);
+ }
+ if (len == 0) { /* first fgets returned NULL */
+ sfree(ret);
+ return NULL;
+ }
+ ret[len] = '\0';
+ return ret;
+}
+
/* ----------------------------------------------------------------------
* Base64 encoding routine. This is required in public-key writing
* but also in HTTP proxy handling, so it's centralised here.
* - return the current size of the buffer chain in bytes
*/
-#define BUFFER_GRANULE 512
+#define BUFFER_MIN_GRANULE 512
struct bufchain_granule {
struct bufchain_granule *next;
- int buflen, bufpos;
- char buf[BUFFER_GRANULE];
+ char *bufpos, *bufend, *bufmax;
};
void bufchain_init(bufchain *ch)
{
const char *buf = (const char *)data;
+ if (len == 0) return;
+
ch->buffersize += len;
- if (ch->tail && ch->tail->buflen < BUFFER_GRANULE) {
- int copylen = min(len, BUFFER_GRANULE - ch->tail->buflen);
- memcpy(ch->tail->buf + ch->tail->buflen, buf, copylen);
- buf += copylen;
- len -= copylen;
- ch->tail->buflen += copylen;
- }
while (len > 0) {
- int grainlen = min(len, BUFFER_GRANULE);
- struct bufchain_granule *newbuf;
- newbuf = snew(struct bufchain_granule);
- newbuf->bufpos = 0;
- newbuf->buflen = grainlen;
- memcpy(newbuf->buf, buf, grainlen);
- buf += grainlen;
- len -= grainlen;
- if (ch->tail)
- ch->tail->next = newbuf;
- else
- ch->head = ch->tail = newbuf;
- newbuf->next = NULL;
- ch->tail = newbuf;
+ if (ch->tail && ch->tail->bufend < ch->tail->bufmax) {
+ int copylen = min(len, ch->tail->bufmax - ch->tail->bufend);
+ memcpy(ch->tail->bufend, buf, copylen);
+ buf += copylen;
+ len -= copylen;
+ ch->tail->bufend += copylen;
+ }
+ if (len > 0) {
+ int grainlen =
+ max(sizeof(struct bufchain_granule) + len, BUFFER_MIN_GRANULE);
+ struct bufchain_granule *newbuf;
+ newbuf = smalloc(grainlen);
+ newbuf->bufpos = newbuf->bufend =
+ (char *)newbuf + sizeof(struct bufchain_granule);
+ newbuf->bufmax = (char *)newbuf + grainlen;
+ newbuf->next = NULL;
+ if (ch->tail)
+ ch->tail->next = newbuf;
+ else
+ ch->head = newbuf;
+ ch->tail = newbuf;
+ }
}
}
while (len > 0) {
int remlen = len;
assert(ch->head != NULL);
- if (remlen >= ch->head->buflen - ch->head->bufpos) {
- remlen = ch->head->buflen - ch->head->bufpos;
+ if (remlen >= ch->head->bufend - ch->head->bufpos) {
+ remlen = ch->head->bufend - ch->head->bufpos;
tmp = ch->head;
ch->head = tmp->next;
- sfree(tmp);
if (!ch->head)
ch->tail = NULL;
+ sfree(tmp);
} else
ch->head->bufpos += remlen;
ch->buffersize -= remlen;
void bufchain_prefix(bufchain *ch, void **data, int *len)
{
- *len = ch->head->buflen - ch->head->bufpos;
- *data = ch->head->buf + ch->head->bufpos;
+ *len = ch->head->bufend - ch->head->bufpos;
+ *data = ch->head->bufpos;
}
void bufchain_fetch(bufchain *ch, void *data, int len)
int remlen = len;
assert(tmp != NULL);
- if (remlen >= tmp->buflen - tmp->bufpos)
- remlen = tmp->buflen - tmp->bufpos;
- memcpy(data_c, tmp->buf + tmp->bufpos, remlen);
+ if (remlen >= tmp->bufend - tmp->bufpos)
+ remlen = tmp->bufend - tmp->bufpos;
+ memcpy(data_c, tmp->bufpos, remlen);
tmp = tmp->next;
len -= remlen;
}
#endif
-void *safemalloc(size_t size)
+void *safemalloc(size_t n, size_t size)
{
void *p;
+
+ if (n > INT_MAX / size) {
+ p = NULL;
+ } else {
+ size *= n;
+ if (size == 0) size = 1;
#ifdef MINEFIELD
- p = minefield_c_malloc(size);
+ p = minefield_c_malloc(size);
#else
- p = malloc(size);
+ p = malloc(size);
#endif
+ }
+
if (!p) {
char str[200];
#ifdef MALLOC_LOG
return p;
}
-void *saferealloc(void *ptr, size_t size)
+void *saferealloc(void *ptr, size_t n, size_t size)
{
void *p;
- if (!ptr) {
+
+ if (n > INT_MAX / size) {
+ p = NULL;
+ } else {
+ size *= n;
+ if (!ptr) {
#ifdef MINEFIELD
- p = minefield_c_malloc(size);
+ p = minefield_c_malloc(size);
#else
- p = malloc(size);
+ p = malloc(size);
#endif
- } else {
+ } else {
#ifdef MINEFIELD
- p = minefield_c_realloc(ptr, size);
+ p = minefield_c_realloc(ptr, size);
#else
- p = realloc(ptr, size);
+ p = realloc(ptr, size);
#endif
+ }
}
+
if (!p) {
char str[200];
#ifdef MALLOC_LOG
if (L) {
int delta;
debug_printf("\t%d (0x%x) bytes:\n", len, len);
- delta = 15 & (int) p;
+ delta = 15 & (unsigned long int) p;
p -= delta;
len += delta;
}
}
#endif /* def DEBUG */
+
+/*
+ * Determine whether or not a Conf represents a session which can
+ * sensibly be launched right now.
+ */
+int conf_launchable(Conf *conf)
+{
+ if (conf_get_int(conf, CONF_protocol) == PROT_SERIAL)
+ return conf_get_str(conf, CONF_serline)[0] != 0;
+ else
+ return conf_get_str(conf, CONF_host)[0] != 0;
+}
+
+char const *conf_dest(Conf *conf)
+{
+ if (conf_get_int(conf, CONF_protocol) == PROT_SERIAL)
+ return conf_get_str(conf, CONF_serline);
+ else
+ return conf_get_str(conf, CONF_host);
+}
+
+#ifndef PLATFORM_HAS_SMEMCLR
+/*
+ * Securely wipe memory.
+ *
+ * The actual wiping is no different from what memset would do: the
+ * point of 'securely' is to try to be sure over-clever compilers
+ * won't optimise away memsets on variables that are about to be freed
+ * or go out of scope. See
+ * https://buildsecurityin.us-cert.gov/bsi-rules/home/g1/771-BSI.html
+ *
+ * Some platforms (e.g. Windows) may provide their own version of this
+ * function.
+ */
+void smemclr(void *b, size_t n) {
+ volatile char *vp;
+
+ if (b && n > 0) {
+ /*
+ * Zero out the memory.
+ */
+ memset(b, 0, n);
+
+ /*
+ * Perform a volatile access to the object, forcing the
+ * compiler to admit that the previous memset was important.
+ *
+ * This while loop should in practice run for zero iterations
+ * (since we know we just zeroed the object out), but in
+ * theory (as far as the compiler knows) it might range over
+ * the whole object. (If we had just written, say, '*vp =
+ * *vp;', a compiler could in principle have 'helpfully'
+ * optimised the memset into only zeroing out the first byte.
+ * This should be robust.)
+ */
+ vp = b;
+ while (*vp) vp++;
+ }
+}
+#endif
projects / u / mdw / putty / blobdiff