Date: Tue, 17 Feb 2015 19:14:17 +0000 (UTC) From: Xin LI <delphij@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r278910 - stable/10/lib/libc/regex Message-ID: <201502171914.t1HJEH57082916@svn.freebsd.org>
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Author: delphij Date: Tue Feb 17 19:14:16 2015 New Revision: 278910 URL: https://svnweb.freebsd.org/changeset/base/278910 Log: MFC r278739: Disallow pattern spaces which would cause intermediate calculations to overflow size_t. Obtained from: DragonFly (2841837793bd095a82f477e9c370cfe6cfb3862c dillon) Security: CERT VU#695940 Modified: stable/10/lib/libc/regex/regcomp.c Directory Properties: stable/10/ (props changed) Modified: stable/10/lib/libc/regex/regcomp.c ============================================================================== --- stable/10/lib/libc/regex/regcomp.c Tue Feb 17 18:33:17 2015 (r278909) +++ stable/10/lib/libc/regex/regcomp.c Tue Feb 17 19:14:16 2015 (r278910) @@ -192,6 +192,7 @@ regcomp(regex_t * __restrict preg, struct parse *p = &pa; int i; size_t len; + size_t maxlen; #ifdef REDEBUG # define GOODFLAGS(f) (f) #else @@ -213,7 +214,23 @@ regcomp(regex_t * __restrict preg, g = (struct re_guts *)malloc(sizeof(struct re_guts)); if (g == NULL) return(REG_ESPACE); + /* + * Limit the pattern space to avoid a 32-bit overflow on buffer + * extension. Also avoid any signed overflow in case of conversion + * so make the real limit based on a 31-bit overflow. + * + * Likely not applicable on 64-bit systems but handle the case + * generically (who are we to stop people from using ~715MB+ + * patterns?). + */ + maxlen = ((size_t)-1 >> 1) / sizeof(sop) * 2 / 3; + if (len >= maxlen) { + free((char *)g); + return(REG_ESPACE); + } p->ssize = len/(size_t)2*(size_t)3 + (size_t)1; /* ugh */ + assert(p->ssize >= len); + p->strip = (sop *)malloc(p->ssize * sizeof(sop)); p->slen = 0; if (p->strip == NULL) {
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