From patchwork Mon Feb 2 19:52:18 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Pluzhnikov X-Patchwork-Id: 4886 Received: (qmail 959 invoked by alias); 2 Feb 2015 19:52:52 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 932 invoked by uid 89); 2 Feb 2015 19:52:52 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=AWL, BAYES_00, RCVD_IN_DNSWL_LOW, SPF_PASS, T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mail-vc0-f177.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-type; bh=y2x6W7UniC3oyXr3LkafgjDlZgAu8sN1KpBBYi/PHmA=; b=QXJuIowePlJXF3jy3lUYvWpnqbl8oO7mMQt3GFKtNCSWFmaIMTT5ukXgG+xWEnPyux xN0dZC2zv9eftENB4dJE2PJhm0BsH1Dp3xmdQL3F9mQIdBFx9CPRiEGCndzy3mMKlu9m esSGZK3p42zygjTj97DZMmppTHVPul6YLOrsGotyum85fNkoCa8jL9Wde8zOELlY4mW+ 0Wmtw7tbAsydfY8fn3t1vOsguyqKoOknigFoZMWKE8R2h/lBR10wdQsa9NF3Y2kC/oVA Ot38lG3x1bJchO3TKrHg3vXGIEZO8/MuWgPx4GTNwBBeHvGkKSdUfwQyiNa9V3tVppTe 7KmA== X-Gm-Message-State: ALoCoQmdTm7pcaYrNYVNpJWLFBI58sjAh657cJDYRP60yJ0XzgRPtgUAUC55DeY4yz2cg3bu16Mv X-Received: by 10.53.13.204 with SMTP id fa12mr11300208vdd.16.1422906768518; Mon, 02 Feb 2015 11:52:48 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <54CFCEB1.8090301@cs.ucla.edu> References: <20150202050906.GF23507@brightrain.aerifal.cx> <54CFCEB1.8090301@cs.ucla.edu> From: Paul Pluzhnikov Date: Mon, 2 Feb 2015 11:52:18 -0800 Message-ID: Subject: Re: [patch] Fix for heap overflow in wscanf (BZ 16618) To: Paul Eggert Cc: Andreas Schwab , Rich Felker , libc-alpha@sourceware.org On Mon, Feb 2, 2015 at 11:23 AM, Paul Eggert wrote: > So, how about the attached (untested) patch to vfscanf.c instead? It's > simpler. It does rely on realloc (wp, SIZE_MAX) returning NULL, but that's > safe in glibc. I like it. Re-tested. Combined patch attached. Thanks, diff --git a/NEWS b/NEWS index c91b9fc..85b2948 100644 --- a/NEWS +++ b/NEWS @@ -10,15 +10,16 @@ Version 2.21 * The following bugs are resolved with this release: 6652, 10672, 12674, 12847, 12926, 13862, 14132, 14138, 14171, 14498, - 15215, 15378, 15884, 16009, 16418, 16191, 16469, 16576, 16617, 16619, - 16657, 16740, 16857, 17192, 17266, 17273, 17344, 17363, 17370, 17371, - 17411, 17460, 17475, 17485, 17501, 17506, 17508, 17522, 17555, 17570, - 17571, 17572, 17573, 17574, 17582, 17583, 17584, 17585, 17589, 17594, - 17601, 17608, 17616, 17625, 17630, 17633, 17634, 17635, 17647, 17653, - 17657, 17658, 17664, 17665, 17668, 17682, 17702, 17717, 17719, 17722, - 17723, 17724, 17725, 17732, 17733, 17744, 17745, 17746, 17747, 17748, - 17775, 17777, 17780, 17781, 17782, 17791, 17793, 17796, 17797, 17801, - 17803, 17806, 17834, 17844, 17848, 17868, 17869, 17870, 17885, 17892. + 15215, 15378, 15884, 16009, 16418, 16191, 16469, 16576, 16617, 16618, + 16619, 16657, 16740, 16857, 17192, 17266, 17273, 17344, 17363, 17370, + 17371, 17411, 17460, 17475, 17485, 17501, 17506, 17508, 17522, 17555, + 17570, 17571, 17572, 17573, 17574, 17582, 17583, 17584, 17585, 17589, + 17594, 17601, 17608, 17616, 17625, 17630, 17633, 17634, 17635, 17647, + 17653, 17657, 17658, 17664, 17665, 17668, 17682, 17702, 17717, 17719, + 17722, 17723, 17724, 17725, 17732, 17733, 17744, 17745, 17746, 17747, + 17748, 17775, 17777, 17780, 17781, 17782, 17791, 17793, 17796, 17797, + 17801, 17803, 17806, 17834, 17844, 17848, 17868, 17869, 17870, 17885, + 17892. * A new semaphore algorithm has been implemented in generic C code for all machines. Previous custom assembly implementations of semaphore were diff --git a/stdio-common/tst-sscanf.c b/stdio-common/tst-sscanf.c index aece3f2..a12333c 100644 --- a/stdio-common/tst-sscanf.c +++ b/stdio-common/tst-sscanf.c @@ -233,5 +233,23 @@ main (void) } } + /* BZ 16618 */ + { +#define SIZE 131072 + CHAR *s = malloc ((SIZE + 1) * sizeof (*s)); + if (s == NULL) + abort (); + for (size_t i = 0; i < SIZE; i++) + s[i] = L('0'); + s[SIZE] = L('\0'); + int i = 42; + if (SSCANF (s, L("%d"), &i) != 1) + result = 1; + if (i != 0) + result = 1; + free (s); +#undef SIZE + } + return result; } diff --git a/stdio-common/vfscanf.c b/stdio-common/vfscanf.c index cd129a8..0e204e7 100644 --- a/stdio-common/vfscanf.c +++ b/stdio-common/vfscanf.c @@ -272,9 +272,10 @@ _IO_vfscanf_internal (_IO_FILE *s, const char *format, _IO_va_list argptr, if (__glibc_unlikely (wpsize == wpmax)) \ { \ CHAR_T *old = wp; \ - size_t newsize = (UCHAR_MAX + 1 > 2 * wpmax \ - ? UCHAR_MAX + 1 : 2 * wpmax); \ - if (use_malloc || !__libc_use_alloca (newsize)) \ + bool fits = __glibc_likely (wpmax <= SIZE_MAX / sizeof (CHAR_T) / 2); \ + size_t wpneed = MAX (UCHAR_MAX + 1, 2 * wpmax); \ + size_t newsize = fits ? wpneed * sizeof (CHAR_T) : SIZE_MAX; \ + if (!__libc_use_alloca (newsize)) \ { \ wp = realloc (use_malloc ? wp : NULL, newsize); \ if (wp == NULL) \ @@ -286,14 +287,13 @@ _IO_vfscanf_internal (_IO_FILE *s, const char *format, _IO_va_list argptr, } \ if (! use_malloc) \ MEMCPY (wp, old, wpsize); \ - wpmax = newsize; \ + wpmax = wpneed; \ use_malloc = true; \ } \ else \ { \ size_t s = wpmax * sizeof (CHAR_T); \ - wp = (CHAR_T *) extend_alloca (wp, s, \ - newsize * sizeof (CHAR_T)); \ + wp = (CHAR_T *) extend_alloca (wp, s, newsize); \ wpmax = s / sizeof (CHAR_T); \ if (old != NULL) \ MEMCPY (wp, old, wpsize); \