Author: pjd
Date: Tue Nov 11 04:48:09 2014
New Revision: 274366
URL: https://svnweb.freebsd.org/changeset/base/274366
Log:
Add missing privilege check when setting the dump device. Before that change
it
was possible for a regular user to setup the dump device if he had write
access
to the given device. In theory it is a security issue as user might get access
to kernel's memory after provoking kernel crash, but in practise it is not
recommended to give regular users direct access to storage devices.
Rework the code so that we do privileges check within the set_dumper()
function
to avoid similar problems in the future.
Discussed with: secteam
Modified:
head/sys/dev/null/null.c
head/sys/geom/geom_dev.c
head/sys/kern/kern_shutdown.c
head/sys/sys/conf.h
Modified: head/sys/dev/null/null.c
==============================================================================
--- head/sys/dev/null/null.c Tue Nov 11 04:07:41 2014 (r274365)
+++ head/sys/dev/null/null.c Tue Nov 11 04:48:09 2014 (r274366)
@@ -37,7 +37,6 @@ __FBSDID("$FreeBSD$");
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
-#include <sys/priv.h>
#include <sys/disk.h>
#include <sys/bus.h>
#include <sys/filio.h>
@@ -110,9 +109,7 @@ null_ioctl(struct cdev *dev __unused, u_
switch (cmd) {
case DIOCSKERNELDUMP:
- error = priv_check(td, PRIV_SETDUMPER);
- if (error == 0)
- error = set_dumper(NULL, NULL);
+ error = set_dumper(NULL, NULL, td);
break;
case FIONBIO:
break;
Modified: head/sys/geom/geom_dev.c
==============================================================================
--- head/sys/geom/geom_dev.c Tue Nov 11 04:07:41 2014 (r274365)
+++ head/sys/geom/geom_dev.c Tue Nov 11 04:48:09 2014 (r274366)
@@ -127,14 +127,14 @@ g_dev_fini(struct g_class *mp)
}
static int
-g_dev_setdumpdev(struct cdev *dev)
+g_dev_setdumpdev(struct cdev *dev, struct thread *td)
{
struct g_kerneldump kd;
struct g_consumer *cp;
int error, len;
if (dev == NULL)
- return (set_dumper(NULL, NULL));
+ return (set_dumper(NULL, NULL, td));
cp = dev->si_drv2;
len = sizeof(kd);
@@ -142,7 +142,7 @@ g_dev_setdumpdev(struct cdev *dev)
kd.length = OFF_MAX;
error = g_io_getattr("GEOM::kerneldump", cp, &len, &kd);
if (error == 0) {
- error = set_dumper(&kd.di, devtoname(dev));
+ error = set_dumper(&kd.di, devtoname(dev), td);
if (error == 0)
dev->si_flags |= SI_DUMPDEV;
}
@@ -157,7 +157,7 @@ init_dumpdev(struct cdev *dev)
return;
if (strcmp(devtoname(dev), dumpdev) != 0)
return;
- if (g_dev_setdumpdev(dev) == 0) {
+ if (g_dev_setdumpdev(dev, curthread) == 0) {
freeenv(dumpdev);
dumpdev = NULL;
}
@@ -453,9 +453,9 @@ g_dev_ioctl(struct cdev *dev, u_long cmd
break;
case DIOCSKERNELDUMP:
if (*(u_int *)data == 0)
- error = g_dev_setdumpdev(NULL);
+ error = g_dev_setdumpdev(NULL, td);
else
- error = g_dev_setdumpdev(dev);
+ error = g_dev_setdumpdev(dev, td);
break;
case DIOCGFLUSH:
error = g_io_flush(cp);
@@ -673,7 +673,7 @@ g_dev_orphan(struct g_consumer *cp)
/* Reset any dump-area set on this device */
if (dev->si_flags & SI_DUMPDEV)
- (void)set_dumper(NULL, NULL);
+ (void)set_dumper(NULL, NULL, curthread);
/* Destroy the struct cdev *so we get no more requests */
destroy_dev_sched_cb(dev, g_dev_callback, cp);
Modified: head/sys/kern/kern_shutdown.c
==============================================================================
--- head/sys/kern/kern_shutdown.c Tue Nov 11 04:07:41 2014
(r274365)
+++ head/sys/kern/kern_shutdown.c Tue Nov 11 04:48:09 2014
(r274366)
@@ -827,9 +827,14 @@ SYSCTL_STRING(_kern_shutdown, OID_AUTO,
/* Registration of dumpers */
int
-set_dumper(struct dumperinfo *di, const char *devname)
+set_dumper(struct dumperinfo *di, const char *devname, struct thread *td)
{
size_t wantcopy;
+ int error;
+
+ error = priv_check(td, PRIV_SETDUMPER);
+ if (error != 0)
+ return (error);
if (di == NULL) {
bzero(&dumper, sizeof dumper);
Modified: head/sys/sys/conf.h
==============================================================================
--- head/sys/sys/conf.h Tue Nov 11 04:07:41 2014 (r274365)
+++ head/sys/sys/conf.h Tue Nov 11 04:48:09 2014 (r274366)
@@ -336,7 +336,7 @@ struct dumperinfo {
off_t mediasize; /* Space available in bytes. */
};
-int set_dumper(struct dumperinfo *, const char *_devname);
+int set_dumper(struct dumperinfo *, const char *_devname, struct thread *td);
int dump_write(struct dumperinfo *, void *, vm_offset_t, off_t, size_t);
int dumpsys(struct dumperinfo *);
int doadump(boolean_t);
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