From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/2718 Path: news.gmane.org!not-for-mail From: "Anthony G. Basile" Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCH] Add support for mkostemp, mkstemps and mkostemps Date: Sat, 02 Feb 2013 15:38:43 -0500 Message-ID: <510D7953.50308@opensource.dyc.edu> References: <1359830731-24717-1-git-send-email-basile@opensource.dyc.edu> <20130202201429.GL6181@port70.net> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1359837544 29264 80.91.229.3 (2 Feb 2013 20:39:04 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 2 Feb 2013 20:39:04 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-2719-gllmg-musl=m.gmane.org@lists.openwall.com Sat Feb 02 21:39:22 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1U1jrq-0000Ls-He for gllmg-musl@plane.gmane.org; Sat, 02 Feb 2013 21:39:18 +0100 Original-Received: (qmail 18398 invoked by uid 550); 2 Feb 2013 20:39:00 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 18390 invoked from network); 2 Feb 2013 20:38:59 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130121 Thunderbird/17.0.2 In-Reply-To: <20130202201429.GL6181@port70.net> Xref: news.gmane.org gmane.linux.lib.musl.general:2718 Archived-At: Okay let me try those fixes. Some points: 1. I forgot to remove a group of headers when I refactorized. So mkostemp.c mkostemps.c mkstemp.c and mkstemps.c only need #include #include "libc.h" or #define _GNU_SOURCE #include "libc.h" 2. This is from uclibc. Clearly, static is critical here, but still they never initialize a value of 'value' on first entry into the function, so that memory is dirty to start. Mine is worse, but I wonder if this is still a bug there. static void brain_damaged_fillrand(unsigned char *buf, unsigned int len) { ... static uint64_t value; gettimeofday(&tv, NULL); value += ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid(); ... 3. I retested your address approach. I like it but it only maps to upper and lower case letters, no numbers which uclibc and glibc do. clock_gettime(CLOCK_REALTIME, &ts); r = ts.tv_nsec*65537 ^ (uintptr_t)&ts / 16 + (uintptr_t)template; for (i=0; i<6; i++, r>>=5) template[i] = 'A'+(r&15)+(r&16)*2; On 02/02/2013 03:14 PM, Szabolcs Nagy wrote: > * Anthony G. Basile [2013-02-02 13:45:31 -0500]: >> + /* Null terminate the template before the suffix, >> + and save the char for adding back the suffix */ >> + char suffix = template[l]; >> + template[l] = '\0'; > > if you set only the XXXXXX part in __randname, then the \0 is unnecessary > >> + int fd, retries = 100; >> + while (retries--) { >> + if (!*__randname(template)) return -1; > > __randname cannot fail, so the check is unnecessary > >> +/* This assumes that a check for the >> + template size has alrady been made */ >> +char *__randname(char *template) >> +{ >> + struct timespec ts; >> + size_t i, l = strlen(template); >> + >> + /* r is intentially uninialized and 'dirty' */ >> + unsigned long r; >> + > > it's undefined behaviour so the compiler is allowed to > completely remove the code of this function > > if you seen this kind of code somewhere, that's a critical > bug that should be reported > > the original address based entropy source was ok > >> + clock_gettime(CLOCK_REALTIME, &ts); >> + r += ((uint64_t) ts.tv_nsec << 16) ^ ts.tv_sec; >> + for (i=1; i<=6; i++, r>>=6) >> + template[l-i] = __map_letter(r); >> + >> + return template; >> +} -- Anthony G. Basile, Ph. D. Chair of Information Technology D'Youville College Buffalo, NY 14201 (716) 829-8197