diff options
| author | Xuan Zhuo <xuanzhuo@linux.alibaba.com> | 2021-07-10 06:16:35 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2021-07-13 18:22:31 +0300 |
| commit | 5acc7d3e8d342858405fbbc671221f676b547ce7 (patch) | |
| tree | 1d61bea620ccea2bebb0228dd3297c5176453d21 /samples | |
| parent | 5dd0a6b8582ffbfa88351949d50eccd5b6694ade (diff) | |
| download | linux-5acc7d3e8d342858405fbbc671221f676b547ce7.tar.xz | |
xdp, net: Fix use-after-free in bpf_xdp_link_release
The problem occurs between dev_get_by_index() and dev_xdp_attach_link().
At this point, dev_xdp_uninstall() is called. Then xdp link will not be
detached automatically when dev is released. But link->dev already
points to dev, when xdp link is released, dev will still be accessed,
but dev has been released.
dev_get_by_index() |
link->dev = dev |
| rtnl_lock()
| unregister_netdevice_many()
| dev_xdp_uninstall()
| rtnl_unlock()
rtnl_lock(); |
dev_xdp_attach_link() |
rtnl_unlock(); |
| netdev_run_todo() // dev released
bpf_xdp_link_release() |
/* access dev. |
use-after-free */ |
[ 45.966867] BUG: KASAN: use-after-free in bpf_xdp_link_release+0x3b8/0x3d0
[ 45.967619] Read of size 8 at addr ffff00000f9980c8 by task a.out/732
[ 45.968297]
[ 45.968502] CPU: 1 PID: 732 Comm: a.out Not tainted 5.13.0+ #22
[ 45.969222] Hardware name: linux,dummy-virt (DT)
[ 45.969795] Call trace:
[ 45.970106] dump_backtrace+0x0/0x4c8
[ 45.970564] show_stack+0x30/0x40
[ 45.970981] dump_stack_lvl+0x120/0x18c
[ 45.971470] print_address_description.constprop.0+0x74/0x30c
[ 45.972182] kasan_report+0x1e8/0x200
[ 45.972659] __asan_report_load8_noabort+0x2c/0x50
[ 45.973273] bpf_xdp_link_release+0x3b8/0x3d0
[ 45.973834] bpf_link_free+0xd0/0x188
[ 45.974315] bpf_link_put+0x1d0/0x218
[ 45.974790] bpf_link_release+0x3c/0x58
[ 45.975291] __fput+0x20c/0x7e8
[ 45.975706] ____fput+0x24/0x30
[ 45.976117] task_work_run+0x104/0x258
[ 45.976609] do_notify_resume+0x894/0xaf8
[ 45.977121] work_pending+0xc/0x328
[ 45.977575]
[ 45.977775] The buggy address belongs to the page:
[ 45.978369] page:fffffc00003e6600 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4f998
[ 45.979522] flags: 0x7fffe0000000000(node=0|zone=0|lastcpupid=0x3ffff)
[ 45.980349] raw: 07fffe0000000000 fffffc00003e6708 ffff0000dac3c010 0000000000000000
[ 45.981309] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[ 45.982259] page dumped because: kasan: bad access detected
[ 45.982948]
[ 45.983153] Memory state around the buggy address:
[ 45.983753] ffff00000f997f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 45.984645] ffff00000f998000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 45.985533] >ffff00000f998080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 45.986419] ^
[ 45.987112] ffff00000f998100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 45.988006] ffff00000f998180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 45.988895] ==================================================================
[ 45.989773] Disabling lock debugging due to kernel taint
[ 45.990552] Kernel panic - not syncing: panic_on_warn set ...
[ 45.991166] CPU: 1 PID: 732 Comm: a.out Tainted: G B 5.13.0+ #22
[ 45.991929] Hardware name: linux,dummy-virt (DT)
[ 45.992448] Call trace:
[ 45.992753] dump_backtrace+0x0/0x4c8
[ 45.993208] show_stack+0x30/0x40
[ 45.993627] dump_stack_lvl+0x120/0x18c
[ 45.994113] dump_stack+0x1c/0x34
[ 45.994530] panic+0x3a4/0x7d8
[ 45.994930] end_report+0x194/0x198
[ 45.995380] kasan_report+0x134/0x200
[ 45.995850] __asan_report_load8_noabort+0x2c/0x50
[ 45.996453] bpf_xdp_link_release+0x3b8/0x3d0
[ 45.997007] bpf_link_free+0xd0/0x188
[ 45.997474] bpf_link_put+0x1d0/0x218
[ 45.997942] bpf_link_release+0x3c/0x58
[ 45.998429] __fput+0x20c/0x7e8
[ 45.998833] ____fput+0x24/0x30
[ 45.999247] task_work_run+0x104/0x258
[ 45.999731] do_notify_resume+0x894/0xaf8
[ 46.000236] work_pending+0xc/0x328
[ 46.000697] SMP: stopping secondary CPUs
[ 46.001226] Dumping ftrace buffer:
[ 46.001663] (ftrace buffer empty)
[ 46.002110] Kernel Offset: disabled
[ 46.002545] CPU features: 0x00000001,23202c00
[ 46.003080] Memory Limit: none
Fixes: aa8d3a716b59db6c ("bpf, xdp: Add bpf_link-based XDP attachment API")
Reported-by: Abaci <abaci@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210710031635.41649-1-xuanzhuo@linux.alibaba.com
Diffstat (limited to 'samples')
0 files changed, 0 insertions, 0 deletions