From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/2684 Path: news.gmane.org!not-for-mail From: Szabolcs Nagy Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCH] Add support for mkostemp, mkstemps and mkostemps Date: Mon, 28 Jan 2013 10:37:55 +0100 Message-ID: <20130128093755.GI10600@port70.net> References: <1359349583-3643-1-git-send-email-basile@opensource.dyc.edu> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1359365887 9038 80.91.229.3 (28 Jan 2013 09:38:07 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 28 Jan 2013 09:38:07 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-2685-gllmg-musl=m.gmane.org@lists.openwall.com Mon Jan 28 10:38:27 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 1TzlAZ-00040K-DU for gllmg-musl@plane.gmane.org; Mon, 28 Jan 2013 10:38:27 +0100 Original-Received: (qmail 26150 invoked by uid 550); 28 Jan 2013 09:38:08 -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 26135 invoked from network); 28 Jan 2013 09:38:07 -0000 Content-Disposition: inline In-Reply-To: <1359349583-3643-1-git-send-email-basile@opensource.dyc.edu> User-Agent: Mutt/1.5.21 (2010-09-15) Xref: news.gmane.org gmane.linux.lib.musl.general:2684 Archived-At: * Anthony G. Basile [2013-01-28 00:06:23 -0500]: > +#include > +#include > +#include > +#include > +#include > +#include "libc.h" libc.h, errno.h, unistd.h are not used > + > +char *__randname(char *template) > +{ > + struct timespec ts; > + size_t i, l = strlen(template); > + unsigned long r; can be unsigned char r; > + > + /* This assumes that a check for the template > + size has alrady been made */ > + clock_gettime(CLOCK_REALTIME, &ts); > + r = ts.tv_nsec + (uintptr_t)&ts / 16 + (uintptr_t)template; > + for (i=1; i<=6; i++, r>>=4) > + template[l-i] = 'A'+(r&15); it seems to use only 4bit entropy based on clock (and fixed addresses) and (uintptr_t)template does not give much entropy if it's malloced and if the clock source is bad for some reason (eg cpu clock mod 16ns is even) then this might not even give different result for each retry (may be it helps if retry count is included) > + > + return template; > +} > diff --git a/src/temp/tempfile.c b/src/temp/tempfile.c i'd use different name, eg __tempfile.c to signify that it's internal > new file mode 100644 > index 0000000..93808a6 > --- /dev/null > +++ b/src/temp/tempfile.c > @@ -0,0 +1,42 @@ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include "libc.h" stdlib.h, limits.h are not used libc.h is not used (in the other files it is needed for weak_alias) > + > +char *__randname(char *); > + > +int __open_tempfile (char *template, int len, int flags) > +{ > + if (len < 0) return EINVAL; > + > + int l = strlen(template)-len; int vs size_t problem > + if (l < 6 || strncmp(template+l-6, "XXXXXX",6)) { > + errno = EINVAL; > + *template = 0; > + return -1; > + } > + > + /* Null terminate the template before the suffix, > + and save the char for adding back the suffix */ > + char suffix = template[l]; > + template[l] = '\0'; > + i'd do __randname(template, length-suffix) so pass the template len as an argument then no suffix saving is needed > + int fd, retries = 100, t0 = *template; 100 retries does not make sense if only 4bit entropy is used (there are 16 different names for the given addresses) > + while (retries--) { > + if (!*__randname(template)) return -1; > + /* Add back the suffix */ > + template[l] = suffix; > + if ((fd = open(template, flags | O_CREAT | O_EXCL, 0600))>=0) > + return fd; > + if (errno != EEXIST) return -1; > + /* this is safe because mktemp verified > + * that we have a valid template string */ > + template[0] = t0; i dont understand why template[0] gets clobbered > + strcpy(template+l-6, "XXXXXX"); i'd use memcpy or memset to avoid suffix saving > + } > + return -1; > +} > -- > 1.7.12.4