Re: [PATCH] kni: fix use-after-free when kni release

["Min Hu (Connor)" <humin29@huawei.com>]

Hi, Igor,
fixed in v2, please check it, thanks.

在 2022/2/8 20:41, Igor Ryzhov 写道:
> Looks correct.
> Could you, please, also change the order of `list_del` and 
> `kni_dev_remove` in `kni_release`? It suffers from the same problem.
> 
> Igor
> 
> On Fri, Jan 28, 2022 at 5:43 AM Min Hu (Connor) <humin29@huawei.com 
> <mailto:humin29@huawei.com>> wrote:
> 
>     From: Huisong Li <lihuisong@huawei.com <mailto:lihuisong@huawei.com>>
> 
>     The "kni_dev" is the private data of the "net_device" in kni, and
>     allocated
>     with the "net_device" by calling "alloc_netdev()". The "net_device" is
>     freed by calling "free_netdev()" when kni release. The freed memory
>     includes the "kni_dev". So After "kni_dev" should not be accessed after
>     "net_device" is released.
> 
>     Fixes: e77fec694936 ("kni: fix possible mbuf leaks and speed up port
>     release")
>     Cc: stable@dpdk.org <mailto:stable@dpdk.org>
> 
>     KASAN trace:
> 
>     [   85.263717]
>     ==========================================================
>     [   85.264418] BUG: KASAN: use-after-free in kni_net_release_fifo_phy+
>                      0x30/0x84 [rte_kni]
>     [   85.265139] Read of size 8 at addr ffff000260668d60 by task kni/341
>     [   85.265703]
>     [   85.265857] CPU: 0 PID: 341 Comm: kni Tainted: G     U     O
>                      5.15.0-rc4+ #1
>     [   85.266525] Hardware name: linux,dummy-virt (DT)
>     [   85.266968] Call trace:
>     [   85.267220]  dump_backtrace+0x0/0x2d0
>     [   85.267591]  show_stack+0x24/0x30
>     [   85.267924]  dump_stack_lvl+0x8c/0xb8
>     [   85.268294]  print_address_description.constprop.0+0x74/0x2b8
>     [   85.268855]  kasan_report+0x1e4/0x200
>     [   85.269224]  __asan_load8+0x98/0xd4
>     [   85.269577]  kni_net_release_fifo_phy+0x30/0x84 [rte_kni]
>     [   85.270116]  kni_dev_remove.isra.0+0x50/0x64 [rte_kni]
>     [   85.270630]  kni_ioctl_release+0x254/0x320 [rte_kni]
>     [   85.271136]  kni_ioctl+0x64/0xb0 [rte_kni]
>     [   85.271553]  __arm64_sys_ioctl+0xdc/0x120
>     [   85.271955]  invoke_syscall+0x68/0x1a0
>     [   85.272332]  el0_svc_common.constprop.0+0x90/0x200
>     [   85.272807]  do_el0_svc+0x94/0xa4
>     [   85.273144]  el0_svc+0x78/0x240
>     [   85.273463]  el0t_64_sync_handler+0x1a8/0x1b0
>     [   85.273895]  el0t_64_sync+0x1a0/0x1a4
>     [   85.274264]
>     [   85.274427] Allocated by task 341:
>     [   85.274767]  kasan_save_stack+0x2c/0x60
>     [   85.275157]  __kasan_kmalloc+0x90/0xb4
>     [   85.275533]  __kmalloc_node+0x230/0x594
>     [   85.275917]  kvmalloc_node+0x8c/0x190
>     [   85.276286]  alloc_netdev_mqs+0x70/0x6b0
>     [   85.276678]  kni_ioctl_create+0x224/0xf40 [rte_kni]
>     [   85.277166]  kni_ioctl+0x9c/0xb0 [rte_kni]
>     [   85.277581]  __arm64_sys_ioctl+0xdc/0x120
>     [   85.277980]  invoke_syscall+0x68/0x1a0
>     [   85.278357]  el0_svc_common.constprop.0+0x90/0x200
>     [   85.278830]  do_el0_svc+0x94/0xa4
>     [   85.279172]  el0_svc+0x78/0x240
>     [   85.279491]  el0t_64_sync_handler+0x1a8/0x1b0
>     [   85.279925]  el0t_64_sync+0x1a0/0x1a4
>     [   85.280292]
>     [   85.280454] Freed by task 341:
>     [   85.280763]  kasan_save_stack+0x2c/0x60
>     [   85.281147]  kasan_set_track+0x2c/0x40
>     [   85.281522]  kasan_set_free_info+0x2c/0x50
>     [   85.281930]  __kasan_slab_free+0xdc/0x140
>     [   85.282331]  slab_free_freelist_hook+0x90/0x250
>     [   85.282782]  kfree+0x128/0x580
>     [   85.283099]  kvfree+0x48/0x60
>     [   85.283402]  netdev_freemem+0x34/0x44
>     [   85.283770]  netdev_release+0x50/0x64
>     [   85.284138]  device_release+0xa0/0x120
>     [   85.284516]  kobject_put+0xf8/0x160
>     [   85.284867]  put_device+0x20/0x30
>     [   85.285204]  free_netdev+0x22c/0x310
>     [   85.285562]  kni_dev_remove.isra.0+0x48/0x64 [rte_kni]
>     [   85.286076]  kni_ioctl_release+0x254/0x320 [rte_kni]
>     [   85.286573]  kni_ioctl+0x64/0xb0 [rte_kni]
>     [   85.286992]  __arm64_sys_ioctl+0xdc/0x120
>     [   85.287392]  invoke_syscall+0x68/0x1a0
>     [   85.287769]  el0_svc_common.constprop.0+0x90/0x200
>     [   85.288243]  do_el0_svc+0x94/0xa4
>     [   85.288579]  el0_svc+0x78/0x240
>     [   85.288899]  el0t_64_sync_handler+0x1a8/0x1b0
>     [   85.289332]  el0t_64_sync+0x1a0/0x1a4
>     [   85.289699]
>     [   85.289862] The buggy address belongs to the object at
>     ffff000260668000
>     [   85.289862]  which belongs to the cache kmalloc-cg-8k of size 8192
>     [   85.291079] The buggy address is located 3424 bytes inside of
>     [   85.291079]  8192-byte region [ffff000260668000, ffff00026066a000)
>     [   85.292213] The buggy address belongs to the page:
>     [   85.292684] page:(____ptrval____) refcount:1 mapcount:0 mapping:
>                      0000000000000000 index:0x0 pfn:0x2a0668
>     [   85.293585] head:(____ptrval____) order:3 compound_mapcount:0
>                      compound_pincount:0
>     [   85.294305] flags: 0xbfff80000010200(slab|head|node=0|zone=2|
>                      lastcpupid=0x7fff)
>     [   85.295020] raw: 0bfff80000010200 0000000000000000 dead000000000122
>                      ffff0000c000d680
>     [   85.295767] raw: 0000000000000000 0000000080020002 00000001ffffffff
>                      0000000000000000
>     [   85.296512] page dumped because: kasan: bad access detected
>     [   85.297054]
>     [   85.297217] Memory state around the buggy address:
>     [   85.297688]  ffff000260668c00: fb fb fb fb fb fb fb fb fb fb fb
>     fb fb fb
>                      fb fb
>     [   85.298384]  ffff000260668c80: fb fb fb fb fb fb fb fb fb fb fb
>     fb fb fb
>                      fb fb
>     [   85.299088] >ffff000260668d00: fb fb fb fb fb fb fb fb fb fb fb
>     fb fb fb
>                      fb fb
>     [   85.299781]                                                        ^
>     [   85.300396]  ffff000260668d80: fb fb fb fb fb fb fb fb fb fb fb
>     fb fb fb
>                      fb fb
>     [   85.301092]  ffff000260668e00: fb fb fb fb fb fb fb fb fb fb fb
>     fb fb fb
>                      fb fb
>     [   85.301787]
>     ===========================================================
> 
>     Signed-off-by: Huisong Li <lihuisong@huawei.com
>     <mailto:lihuisong@huawei.com>>
>     Signed-off-by: Min Hu (Connor) <humin29@huawei.com
>     <mailto:humin29@huawei.com>>
>     ---
>       kernel/linux/kni/kni_misc.c | 10 +++++++---
>       1 file changed, 7 insertions(+), 3 deletions(-)
> 
>     diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c
>     index f10dcd069d..b3684c4fa6 100644
>     --- a/kernel/linux/kni/kni_misc.c
>     +++ b/kernel/linux/kni/kni_misc.c
>     @@ -184,13 +184,17 @@ kni_dev_remove(struct kni_dev *dev)
>              if (!dev)
>                      return -ENODEV;
> 
>     +       /*
>     +        * The memory of kni device is allocated and released together
>     +        * with net device. Release mbuf before freeing net device.
>     +        */
>     +       kni_net_release_fifo_phy(dev);
>     +
>              if (dev->net_dev) {
>                      unregister_netdev(dev->net_dev);
>                      free_netdev(dev->net_dev);
>              }
> 
>     -       kni_net_release_fifo_phy(dev);
>     -
>              return 0;
>       }
> 
>     @@ -470,8 +474,8 @@ kni_ioctl_release(struct net *net, uint32_t
>     ioctl_num,
>                              dev->pthread = NULL;
>                      }
> 
>     -               kni_dev_remove(dev);
>                      list_del(&dev->list);
>     +               kni_dev_remove(dev);
>                      ret = 0;
>                      break;
>              }
>     -- 
>     2.33.0
>