Aren
/
NetBSD
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Repair accidental regression in -r1.49: for -a mode, don't allow 

calendars to be other than regular files unless the -x option is in
effect.

(If not in -a mode, we're running purely as the user whose calendar it
is and if they want to DoS themselves with named pipes it's their own
lookout.)
This commit is contained in:
dholland 2015-07-01 06:48:25 +00:00
parent c1180ac6a1
commit 3b1701b0a5
1 changed files with 74 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
usr.bin/calendar/calendar.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: calendar.c,v 1.51 2015/07/01 06:45:51 dholland Exp $ */
/* $NetBSD: calendar.c,v 1.52 2015/07/01 06:48:25 dholland Exp $ */
/*
* Copyright (c) 1989, 1993, 1994
@ -39,10 +39,11 @@ __COPYRIGHT("@(#) Copyright (c) 1989, 1993\
#if 0
static char sccsid[] = "@(#)calendar.c 8.4 (Berkeley) 1/7/95";
#endif
__RCSID("$NetBSD: calendar.c,v 1.51 2015/07/01 06:45:51 dholland Exp $");
__RCSID("$NetBSD: calendar.c,v 1.52 2015/07/01 06:48:25 dholland Exp $");
#endif /* not lint */
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/uio.h>
@ -120,6 +121,7 @@ static void getmmdd(struct tm *, char *);
static int getmonth(char *);
static bool isnow(char *);
static FILE *opencal(FILE **);
static int tryopen(const char *, int);
static void settime(void);
static void usage(void) __dead;
@ -403,7 +405,7 @@ opencal(FILE **in)
/* open up calendar file as stdin */
if (fname == NULL) {
for (const char **name = defaultnames; *name != NULL; name++) {
if ((fd = open(*name, O_RDONLY)) == -1)
if ((fd = tryopen(*name, O_RDONLY)) == -1)
continue;
else
break;
@ -413,7 +415,7 @@ opencal(FILE **in)
return NULL;
err(EXIT_FAILURE, "Cannot open calendar file");
}
} else if ((fd = open(fname, O_RDONLY)) == -1) {
} else if ((fd = tryopen(fname, O_RDONLY)) == -1) {
if (doall)
return NULL;
err(EXIT_FAILURE, "Cannot open `%s'", fname);
@ -482,6 +484,74 @@ opencal(FILE **in)
/*NOTREACHED*/
}
static int
tryopen(const char *pathname, int flags)
{
int fd, serrno, zero;
struct stat st;
/*
* XXX: cpp_restricted has inverted sense; it is false by default,
* and -x sets it to true. CPP_RESTRICTED is set in the environment
* if cpp_restricted is false... go figure. This should be fixed
* later.
*/
if (doall && cpp_restricted == false) {
/*
* We are running with the user's euid, so they can't
* cause any mayhem (e.g. opening rewinding tape
* devices) that they couldn't do easily enough on
* their own. All we really need to worry about is opens
* that hang, because that would DoS the calendar run.
*/
fd = open(pathname, flags | O_NONBLOCK);
if (fd == -1) {
return -1;
}
if (fstat(fd, &st) == -1) {
serrno = errno;
close(fd);
errno = serrno;
return -1;
}
if (S_ISCHR(st.st_mode) ||
S_ISBLK(st.st_mode) ||
S_ISFIFO(st.st_mode)) {
close(fd);
/* Call shenanigans in the daily output */
errno = EPERM;
warn("%s: %s", pw->pw_name, pathname);
errno = EPERM;
return -1;
}
if (S_ISDIR(st.st_mode)) {
/* Don't warn about this */
close(fd);
errno = EISDIR;
return -1;
}
if (!S_ISREG(st.st_mode)) {
/* There shouldn't be other cases to go here */
close(fd);
errno = EINVAL;
return -1;
}
zero = 0;
if (ioctl(fd, FIONBIO, &zero) == -1) {
serrno = errno;
warn("%s: %s: FIONBIO", pw->pw_name, pathname);
close(fd);
errno = serrno;
return -1;
}
return fd;
} else {
return open(pathname, flags);
}
}
static void
closecal(FILE *fp)
{