Revision 2172fa709ab32ca60e86179dc67d0857be8e2c98 authored by Stephen Smalley on 30 January 2014, 16:26:59 UTC, committed by Paul Moore on 05 February 2014, 17:20:51 UTC
Setting an empty security context (length=0) on a file will lead to incorrectly dereferencing the type and other fields of the security context structure, yielding a kernel BUG. As a zero-length security context is never valid, just reject all such security contexts whether coming from userspace via setxattr or coming from the filesystem upon a getxattr request by SELinux. Setting a security context value (empty or otherwise) unknown to SELinux in the first place is only possible for a root process (CAP_MAC_ADMIN), and, if running SELinux in enforcing mode, only if the corresponding SELinux mac_admin permission is also granted to the domain by policy. In Fedora policies, this is only allowed for specific domains such as livecd for setting down security contexts that are not defined in the build host policy. Reproducer: su setenforce 0 touch foo setfattr -n security.selinux foo Caveat: Relabeling or removing foo after doing the above may not be possible without booting with SELinux disabled. Any subsequent access to foo after doing the above will also trigger the BUG. BUG output from Matthew Thode: [ 473.893141] ------------[ cut here ]------------ [ 473.962110] kernel BUG at security/selinux/ss/services.c:654! [ 473.995314] invalid opcode: 0000 [#6] SMP [ 474.027196] Modules linked in: [ 474.058118] CPU: 0 PID: 8138 Comm: ls Tainted: G D I 3.13.0-grsec #1 [ 474.116637] Hardware name: Supermicro X8ST3/X8ST3, BIOS 2.0 07/29/10 [ 474.149768] task: ffff8805f50cd010 ti: ffff8805f50cd488 task.ti: ffff8805f50cd488 [ 474.183707] RIP: 0010:[<ffffffff814681c7>] [<ffffffff814681c7>] context_struct_compute_av+0xce/0x308 [ 474.219954] RSP: 0018:ffff8805c0ac3c38 EFLAGS: 00010246 [ 474.252253] RAX: 0000000000000000 RBX: ffff8805c0ac3d94 RCX: 0000000000000100 [ 474.287018] RDX: ffff8805e8aac000 RSI: 00000000ffffffff RDI: ffff8805e8aaa000 [ 474.321199] RBP: ffff8805c0ac3cb8 R08: 0000000000000010 R09: 0000000000000006 [ 474.357446] R10: 0000000000000000 R11: ffff8805c567a000 R12: 0000000000000006 [ 474.419191] R13: ffff8805c2b74e88 R14: 00000000000001da R15: 0000000000000000 [ 474.453816] FS: 00007f2e75220800(0000) GS:ffff88061fc00000(0000) knlGS:0000000000000000 [ 474.489254] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 474.522215] CR2: 00007f2e74716090 CR3: 00000005c085e000 CR4: 00000000000207f0 [ 474.556058] Stack: [ 474.584325] ffff8805c0ac3c98 ffffffff811b549b ffff8805c0ac3c98 ffff8805f1190a40 [ 474.618913] ffff8805a6202f08 ffff8805c2b74e88 00068800d0464990 ffff8805e8aac860 [ 474.653955] ffff8805c0ac3cb8 000700068113833a ffff880606c75060 ffff8805c0ac3d94 [ 474.690461] Call Trace: [ 474.723779] [<ffffffff811b549b>] ? lookup_fast+0x1cd/0x22a [ 474.778049] [<ffffffff81468824>] security_compute_av+0xf4/0x20b [ 474.811398] [<ffffffff8196f419>] avc_compute_av+0x2a/0x179 [ 474.843813] [<ffffffff8145727b>] avc_has_perm+0x45/0xf4 [ 474.875694] [<ffffffff81457d0e>] inode_has_perm+0x2a/0x31 [ 474.907370] [<ffffffff81457e76>] selinux_inode_getattr+0x3c/0x3e [ 474.938726] [<ffffffff81455cf6>] security_inode_getattr+0x1b/0x22 [ 474.970036] [<ffffffff811b057d>] vfs_getattr+0x19/0x2d [ 475.000618] [<ffffffff811b05e5>] vfs_fstatat+0x54/0x91 [ 475.030402] [<ffffffff811b063b>] vfs_lstat+0x19/0x1b [ 475.061097] [<ffffffff811b077e>] SyS_newlstat+0x15/0x30 [ 475.094595] [<ffffffff8113c5c1>] ? __audit_syscall_entry+0xa1/0xc3 [ 475.148405] [<ffffffff8197791e>] system_call_fastpath+0x16/0x1b [ 475.179201] Code: 00 48 85 c0 48 89 45 b8 75 02 0f 0b 48 8b 45 a0 48 8b 3d 45 d0 b6 00 8b 40 08 89 c6 ff ce e8 d1 b0 06 00 48 85 c0 49 89 c7 75 02 <0f> 0b 48 8b 45 b8 4c 8b 28 eb 1e 49 8d 7d 08 be 80 01 00 00 e8 [ 475.255884] RIP [<ffffffff814681c7>] context_struct_compute_av+0xce/0x308 [ 475.296120] RSP <ffff8805c0ac3c38> [ 475.328734] ---[ end trace f076482e9d754adc ]--- Reported-by: Matthew Thode <mthode@mthode.org> Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Cc: stable@vger.kernel.org Signed-off-by: Paul Moore <pmoore@redhat.com>
1 parent 6a96e15
gpio-tps6586x.c
/*
* TI TPS6586x GPIO driver
*
* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
* Author: Laxman dewangan <ldewangan@nvidia.com>
*
* Based on tps6586x.c
* Copyright (c) 2010 CompuLab Ltd.
* Mike Rapoport <mike@compulab.co.il>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mfd/tps6586x.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
/* GPIO control registers */
#define TPS6586X_GPIOSET1 0x5d
#define TPS6586X_GPIOSET2 0x5e
struct tps6586x_gpio {
struct gpio_chip gpio_chip;
struct device *parent;
};
static inline struct tps6586x_gpio *to_tps6586x_gpio(struct gpio_chip *chip)
{
return container_of(chip, struct tps6586x_gpio, gpio_chip);
}
static int tps6586x_gpio_get(struct gpio_chip *gc, unsigned offset)
{
struct tps6586x_gpio *tps6586x_gpio = to_tps6586x_gpio(gc);
uint8_t val;
int ret;
ret = tps6586x_read(tps6586x_gpio->parent, TPS6586X_GPIOSET2, &val);
if (ret)
return ret;
return !!(val & (1 << offset));
}
static void tps6586x_gpio_set(struct gpio_chip *gc, unsigned offset,
int value)
{
struct tps6586x_gpio *tps6586x_gpio = to_tps6586x_gpio(gc);
tps6586x_update(tps6586x_gpio->parent, TPS6586X_GPIOSET2,
value << offset, 1 << offset);
}
static int tps6586x_gpio_output(struct gpio_chip *gc, unsigned offset,
int value)
{
struct tps6586x_gpio *tps6586x_gpio = to_tps6586x_gpio(gc);
uint8_t val, mask;
tps6586x_gpio_set(gc, offset, value);
val = 0x1 << (offset * 2);
mask = 0x3 << (offset * 2);
return tps6586x_update(tps6586x_gpio->parent, TPS6586X_GPIOSET1,
val, mask);
}
static int tps6586x_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
{
struct tps6586x_gpio *tps6586x_gpio = to_tps6586x_gpio(gc);
return tps6586x_irq_get_virq(tps6586x_gpio->parent,
TPS6586X_INT_PLDO_0 + offset);
}
static int tps6586x_gpio_probe(struct platform_device *pdev)
{
struct tps6586x_platform_data *pdata;
struct tps6586x_gpio *tps6586x_gpio;
int ret;
pdata = dev_get_platdata(pdev->dev.parent);
tps6586x_gpio = devm_kzalloc(&pdev->dev,
sizeof(*tps6586x_gpio), GFP_KERNEL);
if (!tps6586x_gpio) {
dev_err(&pdev->dev, "Could not allocate tps6586x_gpio\n");
return -ENOMEM;
}
tps6586x_gpio->parent = pdev->dev.parent;
tps6586x_gpio->gpio_chip.owner = THIS_MODULE;
tps6586x_gpio->gpio_chip.label = pdev->name;
tps6586x_gpio->gpio_chip.dev = &pdev->dev;
tps6586x_gpio->gpio_chip.ngpio = 4;
tps6586x_gpio->gpio_chip.can_sleep = 1;
/* FIXME: add handling of GPIOs as dedicated inputs */
tps6586x_gpio->gpio_chip.direction_output = tps6586x_gpio_output;
tps6586x_gpio->gpio_chip.set = tps6586x_gpio_set;
tps6586x_gpio->gpio_chip.get = tps6586x_gpio_get;
tps6586x_gpio->gpio_chip.to_irq = tps6586x_gpio_to_irq;
#ifdef CONFIG_OF_GPIO
tps6586x_gpio->gpio_chip.of_node = pdev->dev.parent->of_node;
#endif
if (pdata && pdata->gpio_base)
tps6586x_gpio->gpio_chip.base = pdata->gpio_base;
else
tps6586x_gpio->gpio_chip.base = -1;
ret = gpiochip_add(&tps6586x_gpio->gpio_chip);
if (ret < 0) {
dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, tps6586x_gpio);
return ret;
}
static int tps6586x_gpio_remove(struct platform_device *pdev)
{
struct tps6586x_gpio *tps6586x_gpio = platform_get_drvdata(pdev);
return gpiochip_remove(&tps6586x_gpio->gpio_chip);
}
static struct platform_driver tps6586x_gpio_driver = {
.driver.name = "tps6586x-gpio",
.driver.owner = THIS_MODULE,
.probe = tps6586x_gpio_probe,
.remove = tps6586x_gpio_remove,
};
static int __init tps6586x_gpio_init(void)
{
return platform_driver_register(&tps6586x_gpio_driver);
}
subsys_initcall(tps6586x_gpio_init);
static void __exit tps6586x_gpio_exit(void)
{
platform_driver_unregister(&tps6586x_gpio_driver);
}
module_exit(tps6586x_gpio_exit);
MODULE_ALIAS("platform:tps6586x-gpio");
MODULE_DESCRIPTION("GPIO interface for TPS6586X PMIC");
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_LICENSE("GPL");
![swh spinner](/static/img/swh-spinner.gif)
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