Date: Fri, 18 Jan 2002 12:46:51 +0100 (CET) From: Hartmut Brandt <brandt@fokus.gmd.de> To: FreeBSD-gnats-submit@freebsd.org Subject: bin/34022: syslog(3) clobbers static storage used by ctime(3) Message-ID: <200201181146.g0IBkp672380@fokus.gmd.de>
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>Number: 34022
>Category: bin
>Synopsis: syslog(3) clobbers static storage used by ctime(3)
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Jan 18 03:50:02 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Hartmut Brandt
>Release: FreeBSD 5.0-CURRENT i386
>Organization:
Fraunhofer FOKUS
>Environment:
System: FreeBSD beagle.fokus.gmd.de 5.0-CURRENT FreeBSD 5.0-CURRENT #7: Fri Jan 11 13:15:44 CET 2002 hbb@beagle.fokus.gmd.de:/opt/obj/usr/src/sys/BEAGLE i386
>Description:
syslog(3) calls ctime() to put a timestamp into the line
that is to be logged. ctime() in turn calls localtime() and
so ctime() clobbers the static storage used for the string by
itself and the static storage used by localtime() for a struct tm.
>How-To-Repeat:
put the line
syslog(LOG_ERR, "timestamp %s", ctime(&t));
into a program using syslog(3) with a value of t that is different
from the current time. Observe, that the two times printed in the
log file are the same.
>Fix:
Apply the following fix to /usr/src/lib/libc/gen/syslog.c:
Index: syslog.c
===================================================================
RCS file: /usr/ncvs/src/lib/libc/gen/syslog.c,v
retrieving revision 1.22
diff -c -r1.22 syslog.c
*** syslog.c 24 Jan 2001 12:59:24 -0000 1.22
--- syslog.c 18 Jan 2002 11:18:32 -0000
***************
*** 143,149 ****
register char ch, *p;
time_t now;
int fd, saved_errno;
! char *stdp, tbuf[2048], fmt_cpy[1024];
FILE *fp, *fmt_fp;
struct bufcookie tbuf_cookie;
struct bufcookie fmt_cookie;
--- 143,149 ----
register char ch, *p;
time_t now;
int fd, saved_errno;
! char *stdp, tbuf[2048], fmt_cpy[1024], timbuf[26];
FILE *fp, *fmt_fp;
struct bufcookie tbuf_cookie;
struct bufcookie fmt_cookie;
***************
*** 176,182 ****
/* Build the message. */
(void)time(&now);
(void)fprintf(fp, "<%d>", pri);
! (void)fprintf(fp, "%.15s ", ctime(&now) + 4);
if (LogStat & LOG_PERROR) {
/* Transfer to string buffer */
(void)fflush(fp);
--- 176,182 ----
/* Build the message. */
(void)time(&now);
(void)fprintf(fp, "<%d>", pri);
! (void)fprintf(fp, "%.15s ", ctime_r(&now, timbuf) + 4);
if (LogStat & LOG_PERROR) {
/* Transfer to string buffer */
(void)fflush(fp);
>Release-Note:
>Audit-Trail:
>Unformatted:
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