1
0
mirror of git://anongit.mindrot.org/openssh.git synced 2024-12-23 10:22:39 +00:00
openssh/utf8.c
deraadt@openbsd.org 9e509d4ec9 upstream commit
Switch to recallocarray() for a few operations.  Both
growth and shrinkage are handled safely, and there also is no need for
preallocation dances. Future changes in this area will be less error prone.
Review and one bug found by markus

Upstream-ID: 822d664d6a5a1d10eccb23acdd53578a679d5065
2017-06-01 14:55:22 +10:00

336 lines
7.9 KiB
C

/* $OpenBSD: utf8.c,v 1.7 2017/05/31 09:15:42 deraadt Exp $ */
/*
* Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Utility functions for multibyte-character handling,
* in particular to sanitize untrusted strings for terminal output.
*/
#include "includes.h"
#include <sys/types.h>
#ifdef HAVE_LANGINFO_H
# include <langinfo.h>
#endif
#include <limits.h>
#include <locale.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS)
# include <vis.h>
#endif
#ifdef HAVE_WCHAR_H
# include <wchar.h>
#endif
#include "utf8.h"
static int dangerous_locale(void);
static int grow_dst(char **, size_t *, size_t, char **, size_t);
static int vasnmprintf(char **, size_t, int *, const char *, va_list);
/*
* For US-ASCII and UTF-8 encodings, we can safely recover from
* encoding errors and from non-printable characters. For any
* other encodings, err to the side of caution and abort parsing:
* For state-dependent encodings, recovery is impossible.
* For arbitrary encodings, replacement of non-printable
* characters would be non-trivial and too fragile.
*/
static int
dangerous_locale(void) {
char *loc;
loc = nl_langinfo(CODESET);
return strcmp(loc, "US-ASCII") != 0 && strcmp(loc, "UTF-8") != 0 &&
strcmp(loc, "ANSI_X3.4-1968") != 0 && strcmp(loc, "646") != 0 &&
strcmp(loc, "") != 0;
}
static int
grow_dst(char **dst, size_t *sz, size_t maxsz, char **dp, size_t need)
{
char *tp;
size_t tsz;
if (*dp + need < *dst + *sz)
return 0;
tsz = *sz + 128;
if (tsz > maxsz)
tsz = maxsz;
if ((tp = recallocarray(*dst, *sz, tsz, 1)) == NULL)
return -1;
*dp = tp + (*dp - *dst);
*dst = tp;
*sz = tsz;
return 0;
}
/*
* The following two functions limit the number of bytes written,
* including the terminating '\0', to sz. Unless wp is NULL,
* they limit the number of display columns occupied to *wp.
* Whichever is reached first terminates the output string.
* To stay close to the standard interfaces, they return the number of
* non-NUL bytes that would have been written if both were unlimited.
* If wp is NULL, newline, carriage return, and tab are allowed;
* otherwise, the actual number of columns occupied by what was
* written is returned in *wp.
*/
static int
vasnmprintf(char **str, size_t maxsz, int *wp, const char *fmt, va_list ap)
{
char *src; /* Source string returned from vasprintf. */
char *sp; /* Pointer into src. */
char *dst; /* Destination string to be returned. */
char *dp; /* Pointer into dst. */
char *tp; /* Temporary pointer for dst. */
size_t sz; /* Number of bytes allocated for dst. */
wchar_t wc; /* Wide character at sp. */
int len; /* Number of bytes in the character at sp. */
int ret; /* Number of bytes needed to format src. */
int width; /* Display width of the character wc. */
int total_width, max_width, print;
src = NULL;
if ((ret = vasprintf(&src, fmt, ap)) <= 0)
goto fail;
sz = strlen(src) + 1;
if ((dst = malloc(sz)) == NULL) {
free(src);
ret = -1;
goto fail;
}
if (maxsz > INT_MAX)
maxsz = INT_MAX;
sp = src;
dp = dst;
ret = 0;
print = 1;
total_width = 0;
max_width = wp == NULL ? INT_MAX : *wp;
while (*sp != '\0') {
if ((len = mbtowc(&wc, sp, MB_CUR_MAX)) == -1) {
(void)mbtowc(NULL, NULL, MB_CUR_MAX);
if (dangerous_locale()) {
ret = -1;
break;
}
len = 1;
width = -1;
} else if (wp == NULL &&
(wc == L'\n' || wc == L'\r' || wc == L'\t')) {
/*
* Don't use width uninitialized; the actual
* value doesn't matter because total_width
* is only returned for wp != NULL.
*/
width = 0;
} else if ((width = wcwidth(wc)) == -1 &&
dangerous_locale()) {
ret = -1;
break;
}
/* Valid, printable character. */
if (width >= 0) {
if (print && (dp - dst >= (int)maxsz - len ||
total_width > max_width - width))
print = 0;
if (print) {
if (grow_dst(&dst, &sz, maxsz,
&dp, len) == -1) {
ret = -1;
break;
}
total_width += width;
memcpy(dp, sp, len);
dp += len;
}
sp += len;
if (ret >= 0)
ret += len;
continue;
}
/* Escaping required. */
while (len > 0) {
if (print && (dp - dst >= (int)maxsz - 4 ||
total_width > max_width - 4))
print = 0;
if (print) {
if (grow_dst(&dst, &sz, maxsz,
&dp, 4) == -1) {
ret = -1;
break;
}
tp = vis(dp, *sp, VIS_OCTAL | VIS_ALL, 0);
width = tp - dp;
total_width += width;
dp = tp;
} else
width = 4;
len--;
sp++;
if (ret >= 0)
ret += width;
}
if (len > 0)
break;
}
free(src);
*dp = '\0';
*str = dst;
if (wp != NULL)
*wp = total_width;
/*
* If the string was truncated by the width limit but
* would have fit into the size limit, the only sane way
* to report the problem is using the return value, such
* that the usual idiom "if (ret < 0 || ret >= sz) error"
* works as expected.
*/
if (ret < (int)maxsz && !print)
ret = -1;
return ret;
fail:
if (wp != NULL)
*wp = 0;
if (ret == 0) {
*str = src;
return 0;
} else {
*str = NULL;
return -1;
}
}
int
snmprintf(char *str, size_t sz, int *wp, const char *fmt, ...)
{
va_list ap;
char *cp;
int ret;
va_start(ap, fmt);
ret = vasnmprintf(&cp, sz, wp, fmt, ap);
va_end(ap);
if (cp != NULL) {
(void)strlcpy(str, cp, sz);
free(cp);
} else
*str = '\0';
return ret;
}
/*
* To stay close to the standard interfaces, the following functions
* return the number of non-NUL bytes written.
*/
int
vfmprintf(FILE *stream, const char *fmt, va_list ap)
{
char *str;
int ret;
if ((ret = vasnmprintf(&str, INT_MAX, NULL, fmt, ap)) < 0)
return -1;
if (fputs(str, stream) == EOF)
ret = -1;
free(str);
return ret;
}
int
fmprintf(FILE *stream, const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = vfmprintf(stream, fmt, ap);
va_end(ap);
return ret;
}
int
mprintf(const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = vfmprintf(stdout, fmt, ap);
va_end(ap);
return ret;
}
/*
* Set up libc for multibyte output in the user's chosen locale.
*
* XXX: we are known to have problems with Turkish (i/I confusion) so we
* deliberately fall back to the C locale for now. Longer term we should
* always prefer to select C.[encoding] if possible, but there's no
* standardisation in locales between systems, so we'll need to survey
* what's out there first.
*/
void
msetlocale(void)
{
const char *vars[] = { "LC_ALL", "LC_CTYPE", "LANG", NULL };
char *cp;
int i;
/*
* We can't yet cope with dotless/dotted I in Turkish locales,
* so fall back to the C locale for these.
*/
for (i = 0; vars[i] != NULL; i++) {
if ((cp = getenv(vars[i])) == NULL)
continue;
if (strncasecmp(cp, "TR", 2) != 0)
break;
/*
* If we're in a UTF-8 locale then prefer to use
* the C.UTF-8 locale (or equivalent) if it exists.
*/
if ((strcasestr(cp, "UTF-8") != NULL ||
strcasestr(cp, "UTF8") != NULL) &&
(setlocale(LC_CTYPE, "C.UTF-8") != NULL ||
setlocale(LC_CTYPE, "POSIX.UTF-8") != NULL))
return;
setlocale(LC_CTYPE, "C");
return;
}
/* We can handle this locale */
setlocale(LC_CTYPE, "");
}