Module Name: src Committed By: bouyer Date: Wed Jul 1 07:18:37 UTC 2015
Modified Files: src/usr.bin/calendar [netbsd-5-1]: calendar.c Log Message: Pull up following revision(s) (requested by dholland in ticket #1971): usr.bin/calendar/calendar.c: revision 1.51 Correct privilege handling problems in calendar -a (which runs as root from /etc/daily); do not exec other programs while the real uid is still 0. Also, clear the supplementary groups list up front and call initgroups when becoming another user, to avoid leaking any extra group privileges that we might have. And finally, don't silently ignore errors changing uid and gid; those are serious if they happen. To generate a diff of this commit: cvs rdiff -u -r1.47 -r1.47.12.1 src/usr.bin/calendar/calendar.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/usr.bin/calendar/calendar.c diff -u src/usr.bin/calendar/calendar.c:1.47 src/usr.bin/calendar/calendar.c:1.47.12.1 --- src/usr.bin/calendar/calendar.c:1.47 Tue Sep 30 05:51:41 2008 +++ src/usr.bin/calendar/calendar.c Wed Jul 1 07:18:37 2015 @@ -1,4 +1,4 @@ -/* $NetBSD: calendar.c,v 1.47 2008/09/30 05:51:41 dholland Exp $ */ +/* $NetBSD: calendar.c,v 1.47.12.1 2015/07/01 07:18:37 bouyer Exp $ */ /* * Copyright (c) 1989, 1993, 1994 @@ -39,7 +39,7 @@ __COPYRIGHT("@(#) Copyright (c) 1989, 19 #if 0 static char sccsid[] = "@(#)calendar.c 8.4 (Berkeley) 1/7/95"; #endif -__RCSID("$NetBSD: calendar.c,v 1.47 2008/09/30 05:51:41 dholland Exp $"); +__RCSID("$NetBSD: calendar.c,v 1.47.12.1 2015/07/01 07:18:37 bouyer Exp $"); #endif /* not lint */ #include <sys/param.h> @@ -48,6 +48,7 @@ __RCSID("$NetBSD: calendar.c,v 1.47 2008 #include <sys/uio.h> #include <sys/wait.h> +#include <assert.h> #include <ctype.h> #include <err.h> #include <errno.h> @@ -105,6 +106,7 @@ static const char *months[] = { static void atodays(int, char *, unsigned short *); static void cal(void); static void closecal(FILE *); +static void changeuser(void); static int getday(char *); static int getfield(char *, char **, int *); static void getmmdd(struct tm *, char *); @@ -164,12 +166,24 @@ main(int argc, char **argv) * XXX - This ignores the user's CALENDAR_DIR variable. * Run under user's login shell? */ + if (setgroups(0, NULL) == -1) { + err(EXIT_FAILURE, "setgroups"); + } while ((pw = getpwent()) != NULL) { - (void)setegid(pw->pw_gid); - (void)seteuid(pw->pw_uid); - if (chdir(pw->pw_dir) != -1) + if (setegid(pw->pw_gid) == -1) { + warn("%s: setegid", pw->pw_name); + continue; + } + if (seteuid(pw->pw_uid) == -1) { + warn("%s: seteuid", pw->pw_name); + continue; + } + if (chdir(pw->pw_dir) != -1) { cal(); - (void)seteuid(0); + } + if (seteuid(0) == -1) { + warn("%s: seteuid back to 0", pw->pw_name); + } } } else if ((caldir = getenv("CALENDAR_DIR")) != NULL) { if (chdir(caldir) != -1) @@ -405,6 +419,10 @@ opencal(void) (void)close(pdes[1]); } (void)close(pdes[0]); + if (doall) { + /* become the user properly */ + changeuser(); + } /* tell CPP to only open regular files */ if(!cpp_restricted && setenv("CPP_RESTRICTED", "", 1) == -1) err(EXIT_FAILURE, "Cannot restrict cpp"); @@ -469,6 +487,10 @@ closecal(FILE *fp) (void)close(pdes[0]); } (void)close(pdes[1]); + if (doall) { + /* become the user properly */ + changeuser(); + } (void)execl(_PATH_SENDMAIL, "sendmail", "-i", "-t", "-F", "\"Reminder Service\"", "-f", "root", NULL); err(EXIT_FAILURE, "Cannot exec `%s'", _PATH_SENDMAIL); @@ -492,6 +514,34 @@ done: (void)fclose(fp); continue; } +static void +changeuser(void) +{ + uid_t uid; + gid_t gid; + + uid = geteuid(); + gid = getegid(); + assert(uid == pw->pw_uid); + assert(gid == pw->pw_gid); + + if (seteuid(0) == -1) { + err(EXIT_FAILURE, "%s: changing user: cannot reassert uid 0", + pw->pw_name); + } + if (setgid(gid) == -1) { + err(EXIT_FAILURE, "%s: cannot assume gid %d", + pw->pw_name, (int)gid); + } + if (initgroups(pw->pw_name, gid) == -1) { + err(EXIT_FAILURE, "%s: cannot initgroups", pw->pw_name); + } + if (setuid(uid) == -1) { + err(EXIT_FAILURE, "%s: cannot assume uid %d", + pw->pw_name, (int)uid); + } +} + static int getmonth(char *s) {