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Pull up following revision(s) (requested by riastradh in ticket #1923): 

lib/libc/gen/vis.c: revision 1.75-1.86
	tests/lib/libc/gen/t_vis.c: revision 1.10-1.14

PR 56260: fix out-of-bounds stack read.

vis(3): Avoid nonportable MIN in portable code.

vis(3) tests: Add xfail test for encoding overflow.

From Kyle Evans <kevans%FreeBSD.org@localhost>.
PR lib/57573

vis(3) tests: Expand tests and diagnostic outputs on failure.
PR lib/57573

vis(3) tests: Test another overflow edge case.
Related to PR lib/57573.

vis(3): Make maxolen unsigned size_t, not ssize_t.
It is initialized once either to *dlen, which is unsigned size_t, or
to wcslen(start) * MB_MAX_LEN + 1, and wcslen returns unsigned size_t
too.  So there appears to have never been any reason for this to be
signed.
Part of PR lib/57573.

vis(3): Make mbslength unsigned.
Sprinkle assertions and comments justifying the proposition that it
would never go negative if signed.
Obviates need to worry about mblength > SSIZE_MAX.
Prompted by PR lib/57573.

vis(3): Avoid arithmetic overflow before calloc(3).
Prompted by PR lib/57573.

vis(3): Call wcslen(start) only once.
It had better not change between these two times!
Prompted by PR lib/57573.

vis(3): Avoid potential arithmetic overflow in maxolen.
Can't easily prove that this overflow is impossible, so let's add a
check.
Prompted by PR lib/57573.

vis(3): Fix main part of PR lib/57573.
From Kyle Evans <kevans%FreeBSD.org@localhost>.

vis(3): Fix one more buffer overrun in an edge case.
PR lib/57573

vis(3): Sort includes.  No functional change intended.
Prompted by PR lib/57573.

vis(3): Need <stdint.h> for SIZE_MAX, per C standard.
From Kyle Evans <kevans%FreeBSD.org@localhost>.
Followup to PR lib/57573.

vis(3): Per KNF, sys/param.h comes before sys/types.h.
Which is nice because that's also lexicographic.
This commit is contained in:
martin 2023-12-09 13:10:16 +00:00
parent ab514538ad
commit b5e98a79d9
2 changed files with 202 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

122
lib/libc/gen/vis.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: vis.c,v 1.73.4.1 2018/01/16 14:15:50 martin Exp $ */
/* $NetBSD: vis.c,v 1.73.4.2 2023/12/09 13:10:16 martin Exp $ */
/*-
* Copyright (c) 1989, 1993
@ -57,7 +57,7 @@
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: vis.c,v 1.73.4.1 2018/01/16 14:15:50 martin Exp $");
__RCSID("$NetBSD: vis.c,v 1.73.4.2 2023/12/09 13:10:16 martin Exp $");
#endif /* LIBC_SCCS and not lint */
#ifdef __FBSDID
__FBSDID("$FreeBSD$");
@ -65,13 +65,15 @@ __FBSDID("$FreeBSD$");
#endif
#include "namespace.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/types.h>
#include <assert.h>
#include <vis.h>
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <vis.h>
#include <wchar.h>
#include <wctype.h>
@ -353,12 +355,15 @@ makeextralist(int flags, const char *src)
wchar_t *dst, *d;
size_t len;
const wchar_t *s;
mbstate_t mbstate;
len = strlen(src);
if ((dst = calloc(len + MAXEXTRAS, sizeof(*dst))) == NULL)
return NULL;
if ((flags & VIS_NOLOCALE) || mbstowcs(dst, src, len) == (size_t)-1) {
memset(&mbstate, 0, sizeof(mbstate));
if ((flags & VIS_NOLOCALE)
|| mbsrtowcs(dst, &src, len, &mbstate) == (size_t)-1) {
size_t i;
for (i = 0; i < len; i++)
dst[i] = (wchar_t)(u_char)src[i];
@ -393,20 +398,23 @@ static int
istrsenvisx(char **mbdstp, size_t *dlen, const char *mbsrc, size_t mblength,
int flags, const char *mbextra, int *cerr_ptr)
{
char mbbuf[MB_LEN_MAX];
wchar_t *dst, *src, *pdst, *psrc, *start, *extra;
size_t len, olen;
uint64_t bmsk, wmsk;
wint_t c;
visfun_t f;
int clen = 0, cerr, error = -1, i, shft;
char *mbdst, *mdst;
ssize_t mbslength, maxolen;
char *mbdst, *mbwrite, *mdst;
size_t mbslength;
size_t maxolen;
mbstate_t mbstate;
_DIAGASSERT(mbdstp != NULL);
_DIAGASSERT(mbsrc != NULL || mblength == 0);
_DIAGASSERT(mbextra != NULL);
mbslength = (ssize_t)mblength;
mbslength = mblength;
/*
* When inputing a single character, must also read in the
* next character for nextc, the look-ahead character.
@ -427,6 +435,14 @@ istrsenvisx(char **mbdstp, size_t *dlen, const char *mbsrc, size_t mblength,
* return to the caller.
*/
/*
* Guarantee the arithmetic on input to calloc won't overflow.
*/
if (mbslength > (SIZE_MAX - 1)/16) {
errno = ENOMEM;
return -1;
}
/* Allocate space for the wide char strings */
psrc = pdst = extra = NULL;
mdst = NULL;
@ -458,10 +474,18 @@ istrsenvisx(char **mbdstp, size_t *dlen, const char *mbsrc, size_t mblength,
* stop at NULs because we may be processing a block of data
* that includes NULs.
*/
memset(&mbstate, 0, sizeof(mbstate));
while (mbslength > 0) {
/* Convert one multibyte character to wchar_t. */
if (!cerr)
clen = mbtowc(src, mbsrc, MB_LEN_MAX);
if (!cerr) {
clen = mbrtowc(src, mbsrc,
(mbslength < MB_LEN_MAX
? mbslength
: MB_LEN_MAX),
&mbstate);
assert(clen < 0 || (size_t)clen <= mbslength);
assert(clen <= MB_LEN_MAX);
}
if (cerr || clen < 0) {
/* Conversion error, process as a byte instead. */
*src = (wint_t)(u_char)*mbsrc;
@ -475,6 +499,20 @@ istrsenvisx(char **mbdstp, size_t *dlen, const char *mbsrc, size_t mblength,
*/
clen = 1;
}
/*
* Let n := MIN(mbslength, MB_LEN_MAX). We have:
*
* mbslength >= 1
* mbrtowc(..., n, &mbstate) <= n,
* by the contract of mbrtowc
*
* clen is either
* (a) mbrtowc(..., n, &mbstate), in which case
* clen <= n <= mbslength; or
* (b) 1, in which case clen = 1 <= mbslength.
*/
assert(clen > 0);
assert((size_t)clen <= mbslength);
/* Advance buffer character pointer. */
src++;
/* Advance input pointer by number of bytes read. */
@ -532,11 +570,49 @@ istrsenvisx(char **mbdstp, size_t *dlen, const char *mbsrc, size_t mblength,
* output byte-by-byte here. Else use wctomb().
*/
len = wcslen(start);
maxolen = dlen ? *dlen : (wcslen(start) * MB_LEN_MAX + 1);
if (dlen) {
maxolen = *dlen;
if (maxolen == 0) {
errno = ENOSPC;
goto out;
}
} else {
if (len > (SIZE_MAX - 1)/MB_LEN_MAX) {
errno = ENOSPC;
goto out;
}
maxolen = len*MB_LEN_MAX + 1;
}
olen = 0;
memset(&mbstate, 0, sizeof(mbstate));
for (dst = start; len > 0; len--) {
if (!cerr)
clen = wctomb(mbdst, *dst);
if (!cerr) {
/*
* If we have at least MB_CUR_MAX bytes in the buffer,
* we'll just do the conversion in-place into mbdst. We
* need to be a little more conservative when we get to
* the end of the buffer, as we may not have MB_CUR_MAX
* bytes but we may not need it.
*/
if (maxolen - olen > MB_CUR_MAX)
mbwrite = mbdst;
else
mbwrite = mbbuf;
clen = wcrtomb(mbwrite, *dst, &mbstate);
if (clen > 0 && mbwrite != mbdst) {
/*
* Don't break past our output limit, noting
* that maxolen includes the nul terminator so
* we can't write past maxolen - 1 here.
*/
if (olen + clen >= maxolen) {
errno = ENOSPC;
goto out;
}
memcpy(mbdst, mbwrite, clen);
}
}
if (cerr || clen < 0) {
/*
* Conversion error, process as a byte(s) instead.
@ -551,16 +627,27 @@ istrsenvisx(char **mbdstp, size_t *dlen, const char *mbsrc, size_t mblength,
shft = i * NBBY;
bmsk = (uint64_t)0xffLL << shft;
wmsk |= bmsk;
if ((*dst & wmsk) || i == 0)
if ((*dst & wmsk) || i == 0) {
if (olen + clen + 1 >= maxolen) {
errno = ENOSPC;
goto out;
}
mbdst[clen++] = (char)(
(uint64_t)(*dst & bmsk) >>
shft);
}
}
cerr = 1;
}
/* If this character would exceed our output limit, stop. */
if (olen + clen > (size_t)maxolen)
break;
/*
* We'll be dereferencing mbdst[clen] after this to write the
* nul terminator; the above paths should have checked for a
* possible overflow already.
*/
assert(olen + clen < maxolen);
/* Advance output pointer by number of bytes written. */
mbdst += clen;
/* Advance buffer character pointer. */
@ -570,6 +657,7 @@ istrsenvisx(char **mbdstp, size_t *dlen, const char *mbsrc, size_t mblength,
}
/* Terminate the output string. */
assert(olen < maxolen);
*mbdst = '\0';
if (flags & VIS_NOLOCALE) {

98
tests/lib/libc/gen/t_vis.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: t_vis.c,v 1.9 2017/01/10 15:16:57 christos Exp $ */
/* $NetBSD: t_vis.c,v 1.9.6.1 2023/12/09 13:10:16 martin Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
@ -116,6 +116,23 @@ ATF_TC_BODY(strvis_empty, tc)
ATF_REQUIRE(dst[0] == '\0' && dst[1] == 'a');
}
ATF_TC(strnvis_empty_empty);
ATF_TC_HEAD(strnvis_empty_empty, tc)
{
atf_tc_set_md_var(tc, "descr",
"Test strnvis(3) with empty source and destination");
}
ATF_TC_BODY(strnvis_empty_empty, tc)
{
char dst[] = "fail";
int n;
n = strnvis(dst, 0, "", VIS_SAFE);
ATF_CHECK(memcmp(dst, "fail", sizeof(dst)) == 0);
ATF_CHECK_EQ_MSG(n, -1, "n=%d", n);
}
ATF_TC(strunvis_hex);
ATF_TC_HEAD(strunvis_hex, tc)
{
@ -175,16 +192,95 @@ ATF_TC_BODY(strvis_locale, tc)
}
#endif /* VIS_NOLOCALE */
#define STRVIS_OVERFLOW_MARKER ((char)0xff) /* Arbitrary */
#ifdef VIS_NOLOCALE
ATF_TC(strvis_overflow_mb);
ATF_TC_HEAD(strvis_overflow_mb, tc)
{
atf_tc_set_md_var(tc, "descr", "Test strvis(3) multi-byte overflow");
}
ATF_TC_BODY(strvis_overflow_mb, tc)
{
const char src[] = "\xf0\x9f\xa5\x91";
/* Extra byte to detect overflow */
char dst[sizeof(src) + 1];
unsigned i;
int n;
setlocale(LC_CTYPE, "en_US.UTF-8");
for (i = 0; i < sizeof(dst) - 1; i++) {
memset(dst, STRVIS_OVERFLOW_MARKER, sizeof(dst));
n = strnvis(dst, i, src, VIS_SAFE);
ATF_CHECK_EQ_MSG(dst[i], STRVIS_OVERFLOW_MARKER,
"[%u] dst=[%02hhx %02hhx %02hhx %02hhx %02hhx]"
" STRVIS_OVERFLOW_MARKER=%02hhx",
i, dst[0], dst[1], dst[2], dst[3], dst[4],
STRVIS_OVERFLOW_MARKER);
ATF_CHECK_EQ_MSG(n, -1, "[%u] n=%d", i, n);
}
memset(dst, STRVIS_OVERFLOW_MARKER, sizeof(dst));
n = strnvis(dst, sizeof(dst) - 1, src, VIS_SAFE);
ATF_CHECK_EQ_MSG(dst[sizeof(dst) - 1], STRVIS_OVERFLOW_MARKER,
"[%u] dst=[%02hhx %02hhx %02hhx %02hhx %02hhx %02hhx]"
" STRVIS_OVERFLOW_MARKER=%02hhx",
i, dst[0], dst[1], dst[2], dst[3], dst[4], dst[5],
STRVIS_OVERFLOW_MARKER);
ATF_CHECK_EQ_MSG(n, (int)sizeof(dst) - 2, "n=%d", n);
}
#endif
ATF_TC(strvis_overflow_c);
ATF_TC_HEAD(strvis_overflow_c, tc)
{
atf_tc_set_md_var(tc, "descr", "Test strvis(3) C locale overflow");
}
ATF_TC_BODY(strvis_overflow_c, tc)
{
const char src[] = "AAAA";
/* Extra byte to detect overflow */
char dst[sizeof(src) + 1];
unsigned i;
int n;
for (i = 0; i < sizeof(dst) - 1; i++) {
memset(dst, STRVIS_OVERFLOW_MARKER, sizeof(dst));
n = strnvis(dst, i, src, VIS_SAFE | VIS_NOLOCALE);
ATF_CHECK_EQ_MSG(dst[i], STRVIS_OVERFLOW_MARKER,
"[%u] dst=[%02hhx %02hhx %02hhx %02hhx %02hhx]"
" STRVIS_OVERFLOW_MARKER=%02hhx",
i, dst[0], dst[1], dst[2], dst[3], dst[4],
STRVIS_OVERFLOW_MARKER);
ATF_CHECK_EQ_MSG(n, -1, "[%u] n=%d", i, n);
}
memset(dst, STRVIS_OVERFLOW_MARKER, sizeof(dst));
n = strnvis(dst, sizeof(dst) - 1, src, VIS_SAFE | VIS_NOLOCALE);
ATF_CHECK_EQ_MSG(dst[sizeof(dst) - 1], STRVIS_OVERFLOW_MARKER,
"[%u] dst=[%02hhx %02hhx %02hhx %02hhx %02hhx %02hhx]"
" STRVIS_OVERFLOW_MARKER=%02hhx",
i, dst[0], dst[1], dst[2], dst[3], dst[4], dst[5],
STRVIS_OVERFLOW_MARKER);
ATF_CHECK_EQ_MSG(n, (int)sizeof(dst) - 2, "n=%d", n);
}
ATF_TP_ADD_TCS(tp)
{
ATF_TP_ADD_TC(tp, strvis_basic);
ATF_TP_ADD_TC(tp, strvis_null);
ATF_TP_ADD_TC(tp, strvis_empty);
ATF_TP_ADD_TC(tp, strnvis_empty_empty);
ATF_TP_ADD_TC(tp, strunvis_hex);
#ifdef VIS_NOLOCALE
ATF_TP_ADD_TC(tp, strvis_locale);
ATF_TP_ADD_TC(tp, strvis_overflow_mb);
#endif /* VIS_NOLOCALE */
ATF_TP_ADD_TC(tp, strvis_overflow_c);
return atf_no_error();
}