=============================================================================
BUG kmalloc-192 (Tainted: G E ): kasan: bad access detected
-----------------------------------------------------------------------------
Disabling lock debugging due to kernel taint
INFO: Allocated in vhci_open+0x50/0x330 [hci_vhci] age=260 cpu=3 pid=32040
...
kmem_cache_alloc_trace+0x150/0x190
vhci_open+0x50/0x330 [hci_vhci]
misc_open+0x35b/0x4e0
chrdev_open+0x23b/0x510
...
INFO: Freed in vhci_release+0xa4/0xd0 [hci_vhci] age=9 cpu=2 pid=32040
...
__slab_free+0x204/0x310
vhci_release+0xa4/0xd0 [hci_vhci]
...
INFO: Slab 0xffffea0001ac3000 objects=16 used=13 fp=0xffff88006b0c1e00 flags=0x5fffff80004080
INFO: Object 0xffff88006b0c1200 @offset=4608 fp=0xffff88006b0c0600
Bytes b4 ffff88006b0c11f0: 09 df 00 00 01 00 00 00 00 00 00 00 00 00 00 00 ................
Object ffff88006b0c1200: 00 06 0c 6b 00 88 ff ff 00 00 00 00 00 00 00 00 ...k............
Object ffff88006b0c1210: 10 12 0c 6b 00 88 ff ff 10 12 0c 6b 00 88 ff ff ...k.......k....
Object ffff88006b0c1220: c0 46 c2 6b 00 88 ff ff c0 46 c2 6b 00 88 ff ff .F.k.....F.k....
Object ffff88006b0c1230: 01 00 00 00 01 00 00 00 e0 ff ff ff 0f 00 00 00 ................
Object ffff88006b0c1240: 40 12 0c 6b 00 88 ff ff 40 12 0c 6b 00 88 ff ff @..k....@..k....
Object ffff88006b0c1250: 50 0d 6e a0 ff ff ff ff 00 02 00 00 00 00 ad de P.n.............
Object ffff88006b0c1260: 00 00 00 00 00 00 00 00 ab 62 02 00 01 00 00 00 .........b......
Object ffff88006b0c1270: 90 b9 19 81 ff ff ff ff 38 12 0c 6b 00 88 ff ff ........8..k....
Object ffff88006b0c1280: 03 00 20 00 ff ff ff ff ff ff ff ff 00 00 00 00 .. .............
Object ffff88006b0c1290: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
Object ffff88006b0c12a0: 00 00 00 00 00 00 00 00 00 80 cd 3d 00 88 ff ff ...........=....
Object ffff88006b0c12b0: 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 . ..............
Redzone ffff88006b0c12c0: bb bb bb bb bb bb bb bb ........
Padding ffff88006b0c13f8: 00 00 00 00 00 00 00 00 ........
CPU: 3 PID: 32068 Comm: kworker/u13:1 Tainted: G B E 4.4.6-0-default #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20151112_172657-sheep25 04/01/2014
Workqueue: hci0 hci_cmd_work [bluetooth]
00000000ffffffff ffffffff81926cfa ffff88006be37c68 ffff88006bc27180
ffff88006b0c1200 ffff88006b0c1234 ffffffff81577993 ffffffff82489320
ffff88006bc24240 0000000000000046 ffff88006a100000 000000026e51eb80
Call Trace:
...
[<ffffffff81ec8ebe>] ? skb_queue_tail+0x13e/0x150
[<ffffffffa06e027c>] ? vhci_send_frame+0xac/0x100 [hci_vhci]
[<ffffffffa0c61268>] ? hci_send_frame+0x188/0x320 [bluetooth]
[<ffffffffa0c61515>] ? hci_cmd_work+0x115/0x310 [bluetooth]
[<ffffffff811a1375>] ? process_one_work+0x815/0x1340
[<ffffffff811a1f85>] ? worker_thread+0xe5/0x11f0
[<ffffffff811a1ea0>] ? process_one_work+0x1340/0x1340
[<ffffffff811b3c68>] ? kthread+0x1c8/0x230
...
Memory state around the buggy address:
ffff88006b0c1100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88006b0c1180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88006b0c1200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88006b0c1280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88006b0c1300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
Fixes: 23424c0d31 (Bluetooth: Add support creating virtual AMP controllers)
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
drivers/bluetooth/hci_vhci.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
@@ -197,13 +197,13 @@ static inline ssize_t vhci_get_user(struct vhci_data *data,
break;
case HCI_VENDOR_PKT:
+ cancel_delayed_work_sync(&data->open_timeout);
+
if (data->hdev) {
kfree_skb(skb);
return -EBADFD;
}
- cancel_delayed_work_sync(&data->open_timeout);
-
opcode = *((__u8 *) skb->data);
skb_pull(skb, 1);
@@ -341,10 +341,12 @@ static int vhci_open(struct inode *inode, struct file *file)
static int vhci_release(struct inode *inode, struct file *file)
{
struct vhci_data *data = file->private_data;
- struct hci_dev *hdev = data->hdev;
+ struct hci_dev *hdev;
cancel_delayed_work_sync(&data->open_timeout);
+ hdev = data->hdev;
+
if (hdev) {
hci_unregister_dev(hdev);
hci_free_dev(hdev);
This is a note to let you know that I have just added a patch titled Bluetooth: vhci: fix open_timeout vs. hdev race to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt12. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 485c519c60268fce922a0334574a94ef78ace789 Mon Sep 17 00:00:00 2001 From: Jiri Slaby <jslaby@suse.cz> Date: Sat, 19 Mar 2016 11:05:18 +0100 Subject: Bluetooth: vhci: fix open_timeout vs. hdev race commit 373a32c848ae3a1c03618517cce85f9211a6facf upstream. Both vhci_get_user and vhci_release race with open_timeout work. They both contain cancel_delayed_work_sync, but do not test whether the work actually created hdev or not. Since the work can be in progress and _sync will wait for finishing it, we can have data->hdev allocated when cancel_delayed_work_sync returns. But the call sites do 'if (data->hdev)' *before* cancel_delayed_work_sync. As a result: * vhci_get_user allocates a second hdev and puts it into data->hdev. The former is leaked. * vhci_release does not release data->hdev properly as it thinks there is none. Fix both cases by moving the actual test *after* the call to cancel_delayed_work_sync. This can be hit by this program: #include <err.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <time.h> #include <unistd.h> #include <sys/stat.h> #include <sys/types.h> int main(int argc, char **argv) { int fd; srand(time(NULL)); while (1) { const int delta = (rand() % 200 - 100) * 100; fd = open("/dev/vhci", O_RDWR); if (fd < 0) err(1, "open"); usleep(1000000 + delta); close(fd); } return 0; } And the result is: BUG: KASAN: use-after-free in skb_queue_tail+0x13e/0x150 at addr ffff88006b0c1228 Read of size 8 by task kworker/u13:1/32068 -- 2.7.4