From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
syzbot+582e66e5edf36a22c7b0@syzkaller.appspotmail.com,
Nikolay Borisov <nborisov@suse.com>,
Anand Jain <anand.jain@oracle.com>,
Johannes Thumshirn <johannes.thumshirn@wdc.com>,
David Sterba <dsterba@suse.com>
Subject: [PATCH 4.19 03/57] btrfs: dont access possibly stale fs_info data for printing duplicate device
Date: Tue, 1 Dec 2020 09:53:08 +0100 [thread overview]
Message-ID: <20201201084648.130524023@linuxfoundation.org> (raw)
In-Reply-To: <20201201084647.751612010@linuxfoundation.org>
From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
commit 0697d9a610998b8bdee6b2390836cb2391d8fd1a upstream.
Syzbot reported a possible use-after-free when printing a duplicate device
warning device_list_add().
At this point it can happen that a btrfs_device::fs_info is not correctly
setup yet, so we're accessing stale data, when printing the warning
message using the btrfs_printk() wrappers.
==================================================================
BUG: KASAN: use-after-free in btrfs_printk+0x3eb/0x435 fs/btrfs/super.c:245
Read of size 8 at addr ffff8880878e06a8 by task syz-executor225/7068
CPU: 1 PID: 7068 Comm: syz-executor225 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1d6/0x29e lib/dump_stack.c:118
print_address_description+0x66/0x620 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report+0x132/0x1d0 mm/kasan/report.c:530
btrfs_printk+0x3eb/0x435 fs/btrfs/super.c:245
device_list_add+0x1a88/0x1d60 fs/btrfs/volumes.c:943
btrfs_scan_one_device+0x196/0x490 fs/btrfs/volumes.c:1359
btrfs_mount_root+0x48f/0xb60 fs/btrfs/super.c:1634
legacy_get_tree+0xea/0x180 fs/fs_context.c:592
vfs_get_tree+0x88/0x270 fs/super.c:1547
fc_mount fs/namespace.c:978 [inline]
vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008
btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732
legacy_get_tree+0xea/0x180 fs/fs_context.c:592
vfs_get_tree+0x88/0x270 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x179d/0x29e0 fs/namespace.c:3192
do_mount fs/namespace.c:3205 [inline]
__do_sys_mount fs/namespace.c:3413 [inline]
__se_sys_mount+0x126/0x180 fs/namespace.c:3390
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x44840a
RSP: 002b:00007ffedfffd608 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffedfffd670 RCX: 000000000044840a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffedfffd630
RBP: 00007ffedfffd630 R08: 00007ffedfffd670 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000001a
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003
Allocated by task 6945:
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461
kmalloc_node include/linux/slab.h:577 [inline]
kvmalloc_node+0x81/0x110 mm/util.c:574
kvmalloc include/linux/mm.h:757 [inline]
kvzalloc include/linux/mm.h:765 [inline]
btrfs_mount_root+0xd0/0xb60 fs/btrfs/super.c:1613
legacy_get_tree+0xea/0x180 fs/fs_context.c:592
vfs_get_tree+0x88/0x270 fs/super.c:1547
fc_mount fs/namespace.c:978 [inline]
vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008
btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732
legacy_get_tree+0xea/0x180 fs/fs_context.c:592
vfs_get_tree+0x88/0x270 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x179d/0x29e0 fs/namespace.c:3192
do_mount fs/namespace.c:3205 [inline]
__do_sys_mount fs/namespace.c:3413 [inline]
__se_sys_mount+0x126/0x180 fs/namespace.c:3390
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 6945:
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_set_track+0x3d/0x70 mm/kasan/common.c:56
kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355
__kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422
__cache_free mm/slab.c:3418 [inline]
kfree+0x113/0x200 mm/slab.c:3756
deactivate_locked_super+0xa7/0xf0 fs/super.c:335
btrfs_mount_root+0x72b/0xb60 fs/btrfs/super.c:1678
legacy_get_tree+0xea/0x180 fs/fs_context.c:592
vfs_get_tree+0x88/0x270 fs/super.c:1547
fc_mount fs/namespace.c:978 [inline]
vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008
btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732
legacy_get_tree+0xea/0x180 fs/fs_context.c:592
vfs_get_tree+0x88/0x270 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x179d/0x29e0 fs/namespace.c:3192
do_mount fs/namespace.c:3205 [inline]
__do_sys_mount fs/namespace.c:3413 [inline]
__se_sys_mount+0x126/0x180 fs/namespace.c:3390
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff8880878e0000
which belongs to the cache kmalloc-16k of size 16384
The buggy address is located 1704 bytes inside of
16384-byte region [ffff8880878e0000, ffff8880878e4000)
The buggy address belongs to the page:
page:0000000060704f30 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x878e0
head:0000000060704f30 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00028e9a08 ffffea00021e3608 ffff8880aa440b00
raw: 0000000000000000 ffff8880878e0000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8880878e0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880878e0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880878e0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880878e0700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880878e0780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
The syzkaller reproducer for this use-after-free crafts a filesystem image
and loop mounts it twice in a loop. The mount will fail as the crafted
image has an invalid chunk tree. When this happens btrfs_mount_root() will
call deactivate_locked_super(), which then cleans up fs_info and
fs_info::sb. If a second thread now adds the same block-device to the
filesystem, it will get detected as a duplicate device and
device_list_add() will reject the duplicate and print a warning. But as
the fs_info pointer passed in is non-NULL this will result in a
use-after-free.
Instead of printing possibly uninitialized or already freed memory in
btrfs_printk(), explicitly pass in a NULL fs_info so the printing of the
device name will be skipped altogether.
There was a slightly different approach discussed in
https://lore.kernel.org/linux-btrfs/20200114060920.4527-1-anand.jain@oracle.com/t/#u
Link: https://lore.kernel.org/linux-btrfs/000000000000c9e14b05afcc41ba@google.com
Reported-by: syzbot+582e66e5edf36a22c7b0@syzkaller.appspotmail.com
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/volumes.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -857,7 +857,13 @@ static noinline struct btrfs_device *dev
if (device->bdev != path_bdev) {
bdput(path_bdev);
mutex_unlock(&fs_devices->device_list_mutex);
- btrfs_warn_in_rcu(device->fs_info,
+ /*
+ * device->fs_info may not be reliable here, so
+ * pass in a NULL instead. This avoids a
+ * possible use-after-free when the fs_info and
+ * fs_info->sb are already torn down.
+ */
+ btrfs_warn_in_rcu(NULL,
"duplicate device %s devid %llu generation %llu scanned by %s (%d)",
path, devid, found_transid,
current->comm,
next prev parent reply other threads:[~2020-12-01 9:28 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 8:53 [PATCH 4.19 00/57] 4.19.161-rc1 review Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 01/57] perf event: Check ref_reloc_sym before using it Greg Kroah-Hartman
2020-12-01 8:53 ` Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 02/57] netfilter: clear skb->next in NF_HOOK_LIST() Greg Kroah-Hartman
2020-12-01 8:53 ` Greg Kroah-Hartman [this message]
2020-12-01 8:53 ` [PATCH 4.19 04/57] btrfs: fix lockdep splat when reading qgroup config on mount Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 05/57] wireless: Use linux/stddef.h instead of stddef.h Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 06/57] KVM: arm64: vgic-v3: Drop the reporting of GICR_TYPER.Last for userspace Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 07/57] KVM: x86: handle !lapic_in_kernel case in kvm_cpu_*_extint Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 08/57] KVM: x86: Fix split-irqchip vs interrupt injection window request Greg Kroah-Hartman
2020-12-01 9:06 ` Paolo Bonzini
2020-12-01 9:57 ` Greg Kroah-Hartman
2020-12-01 10:03 ` Paolo Bonzini
2020-12-01 10:20 ` Greg Kroah-Hartman
2020-12-01 10:55 ` Paolo Bonzini
2020-12-01 11:13 ` Greg Kroah-Hartman
2020-12-01 12:07 ` Paolo Bonzini
2020-12-01 15:33 ` Pavel Machek
2020-12-01 15:47 ` Paolo Bonzini
2020-12-01 8:53 ` [PATCH 4.19 09/57] arm64: pgtable: Fix pte_accessible() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 10/57] arm64: pgtable: Ensure dirty bit is preserved across pte_wrprotect() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 11/57] drm/atomic_helper: Stop modesets on unregistered connectors harder Greg Kroah-Hartman
2020-12-01 15:43 ` Pavel Machek
2020-12-01 16:47 ` Daniel Vetter
2020-12-01 8:53 ` [PATCH 4.19 12/57] ALSA: hda/hdmi: fix incorrect locking in hdmi_pcm_close Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 13/57] HID: cypress: Support Varmilo Keyboards media hotkeys Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 14/57] HID: add support for Sega Saturn Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 15/57] Input: i8042 - allow insmod to succeed on devices without an i8042 controller Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 16/57] HID: hid-sensor-hub: Fix issue with devices with no report ID Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 17/57] HID: add HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE for Gamevice devices Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 18/57] dmaengine: xilinx_dma: use readl_poll_timeout_atomic variant Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 19/57] x86/xen: dont unbind uninitialized lock_kicker_irq Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 20/57] HID: Add Logitech Dinovo Edge battery quirk Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 21/57] proc: dont allow async path resolution of /proc/self components Greg Kroah-Hartman
2021-03-02 8:40 ` Yang Yingliang
2021-03-02 17:39 ` Jens Axboe
2020-12-01 8:53 ` [PATCH 4.19 22/57] nvme: free sq/cq dbbuf pointers when dbbuf set fails Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 23/57] dmaengine: pl330: _prep_dma_memcpy: Fix wrong burst size Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 24/57] scsi: libiscsi: Fix NOP race condition Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 25/57] scsi: target: iscsi: Fix cmd abort fabric stop race Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 26/57] perf/x86: fix sysfs type mismatches Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 27/57] xtensa: uaccess: Add missing __user to strncpy_from_user() prototype Greg Kroah-Hartman
2020-12-01 15:52 ` Pavel Machek
2020-12-01 8:53 ` [PATCH 4.19 28/57] phy: tegra: xusb: Fix dangling pointer on probe failure Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 29/57] batman-adv: set .owner to THIS_MODULE Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 30/57] ARM: dts: dra76x: m_can: fix order of clocks Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 31/57] scsi: ufs: Fix race between shutdown and runtime resume flow Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 32/57] bnxt_en: fix error return code in bnxt_init_one() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 33/57] bnxt_en: fix error return code in bnxt_init_board() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 34/57] video: hyperv_fb: Fix the cache type when mapping the VRAM Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 35/57] bnxt_en: Release PCI regions when DMA mask setup fails during probe Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 36/57] cxgb4: fix the panic caused by non smac rewrite Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 37/57] s390/qeth: fix tear down of async TX buffers Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 38/57] IB/mthca: fix return value of error branch in mthca_init_cq() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 39/57] nfc: s3fwrn5: use signed integer for parsing GPIO numbers Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 40/57] net: ena: set initial DMA width to avoid intel iommu issue Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 41/57] ibmvnic: fix NULL pointer dereference in reset_sub_crq_queues Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 42/57] ibmvnic: fix NULL pointer dereference in ibmvic_reset_crq Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 43/57] optee: add writeback to valid memory type Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 44/57] efivarfs: revert "fix memory leak in efivarfs_create()" Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 45/57] can: gs_usb: fix endianess problem with candleLight firmware Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 46/57] platform/x86: thinkpad_acpi: Send tablet mode switch at wakeup time Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 47/57] platform/x86: toshiba_acpi: Fix the wrong variable assignment Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 48/57] can: m_can: fix nominal bitiming tseg2 min for version >= 3.1 Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 49/57] perf probe: Fix to die_entrypc() returns error correctly Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 50/57] USB: core: Change %pK for __user pointers to %px Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 51/57] usb: gadget: f_midi: Fix memleak in f_midi_alloc Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 52/57] USB: quirks: Add USB_QUIRK_DISCONNECT_SUSPEND quirk for Lenovo A630Z TIO built-in usb-audio card Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 53/57] usb: gadget: Fix memleak in gadgetfs_fill_super Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.19 54/57] x86/speculation: Fix prctl() when spectre_v2_user={seccomp,prctl},ibpb Greg Kroah-Hartman
2020-12-01 8:54 ` [PATCH 4.19 55/57] x86/resctrl: Remove superfluous kernfs_get() calls to prevent refcount leak Greg Kroah-Hartman
2020-12-01 8:54 ` [PATCH 4.19 56/57] x86/resctrl: Add necessary kernfs_put() " Greg Kroah-Hartman
2020-12-01 8:54 ` [PATCH 4.19 57/57] USB: core: Fix regression in Hercules audio card Greg Kroah-Hartman
2020-12-01 13:39 ` [PATCH 4.19 00/57] 4.19.161-rc1 review Jon Hunter
2020-12-01 15:59 ` Pavel Machek
2020-12-02 7:48 ` Greg Kroah-Hartman
2020-12-01 21:39 ` Guenter Roeck
2020-12-02 5:11 ` Naresh Kamboju
2020-12-02 17:00 ` Shuah Khan
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