diff options
Diffstat (limited to 'vis.c')
| -rw-r--r-- | vis.c | 116 |
1 files changed, 101 insertions, 15 deletions
@@ -1,4 +1,4 @@ -/* $NetBSD: vis.c,v 1.74 2017/11/27 16:37:21 christos Exp $ */ +/* $NetBSD: vis.c,v 1.83 2023/08/12 12:48:52 riastradh Exp $ */ /*- * Copyright (c) 1989, 1993 @@ -57,7 +57,7 @@ #include <sys/cdefs.h> #if defined(LIBC_SCCS) && !defined(lint) -__RCSID("$NetBSD: vis.c,v 1.74 2017/11/27 16:37:21 christos Exp $"); +__RCSID("$NetBSD: vis.c,v 1.83 2023/08/12 12:48:52 riastradh Exp $"); #endif /* LIBC_SCCS and not lint */ #ifdef __FBSDID __FBSDID("$FreeBSD$"); @@ -353,12 +353,15 @@ 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 +396,23 @@ 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 +433,14 @@ 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 +472,18 @@ 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 +497,20 @@ 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 +568,49 @@ 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 +625,27 @@ 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 +655,7 @@ 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) { |