Subject: Re: [PATCH] net: igbvf: fix double free in `igbvf_probe`
To:     Letu Ren <fantasquex@gmail.com>, jesse.brandeburg@intel.com,
        anthony.l.nguyen@intel.com, davem@davemloft.net, kuba@kernel.org
Cc:     intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Zheyu Ma <zheyuma97@gmail.com>
References: <20211112142002.23156-1-fantasquex@gmail.com>
From:   Denis Kirjanov <dkirjanov@suse.de>
Message-ID: <4246e551-8963-e6aa-a70a-7a7005c7316b@suse.de>
Date:   Fri, 12 Nov 2021 18:08:27 +0300
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11/12/21 5:20 PM, Letu Ren пишет:
> In `igbvf_probe`, if register_netdev() fails, the program will go to
> label err_hw_init, and then to label err_ioremap. In free_netdev() which
> is just below label err_ioremap, there is `list_for_each_entry_safe` and
> `netif_napi_del` which aims to delete all entries in `dev->napi_list`.
> The program has added an entry `adapter->rx_ring->napi` which is added by
> `netif_napi_add` in igbvf_alloc_queues(). However, adapter->rx_ring has
> been freed below label err_hw_init. So this a UAF.
> 
> In terms of how to patch the problem, we can refer to igbvf_remove() and
> delete the entry before `adapter->rx_ring`.
> 
> The KASAN logs are as follows:
> 
> [   35.126075] BUG: KASAN: use-after-free in free_netdev+0x1fd/0x450
> [   35.127170] Read of size 8 at addr ffff88810126d990 by task modprobe/366
> [   35.128360]
> [   35.128643] CPU: 1 PID: 366 Comm: modprobe Not tainted 5.15.0-rc2+ #14
> [   35.129789] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
> [   35.131749] Call Trace:
> [   35.132199]  dump_stack_lvl+0x59/0x7b
> [   35.132865]  print_address_description+0x7c/0x3b0
> [   35.133707]  ? free_netdev+0x1fd/0x450
> [   35.134378]  __kasan_report+0x160/0x1c0
> [   35.135063]  ? free_netdev+0x1fd/0x450
> [   35.135738]  kasan_report+0x4b/0x70
> [   35.136367]  free_netdev+0x1fd/0x450
> [   35.137006]  igbvf_probe+0x121d/0x1a10 [igbvf]
> [   35.137808]  ? igbvf_vlan_rx_add_vid+0x100/0x100 [igbvf]
> [   35.138751]  local_pci_probe+0x13c/0x1f0
> [   35.139461]  pci_device_probe+0x37e/0x6c0
> [   35.165526]
> [   35.165806] Allocated by task 366:
> [   35.166414]  ____kasan_kmalloc+0xc4/0xf0
> [   35.167117]  foo_kmem_cache_alloc_trace+0x3c/0x50 [igbvf]
> [   35.168078]  igbvf_probe+0x9c5/0x1a10 [igbvf]
> [   35.168866]  local_pci_probe+0x13c/0x1f0
> [   35.169565]  pci_device_probe+0x37e/0x6c0
> [   35.179713]
> [   35.179993] Freed by task 366:
> [   35.180539]  kasan_set_track+0x4c/0x80
> [   35.181211]  kasan_set_free_info+0x1f/0x40
> [   35.181942]  ____kasan_slab_free+0x103/0x140
> [   35.182703]  kfree+0xe3/0x250
> [   35.183239]  igbvf_probe+0x1173/0x1a10 [igbvf]
> [   35.184040]  local_pci_probe+0x13c/0x1f0
> 
> Reported-by: Zheyu Ma <zheyuma97@gmail.com>
Please add Fixes tag
> Signed-off-by: Letu Ren <fantasquex@gmail.com>
> ---
>   drivers/net/ethernet/intel/igbvf/netdev.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/ethernet/intel/igbvf/netdev.c b/drivers/net/ethernet/intel/igbvf/netdev.c
> index d32e72d953c8..d051918dfdff 100644
> --- a/drivers/net/ethernet/intel/igbvf/netdev.c
> +++ b/drivers/net/ethernet/intel/igbvf/netdev.c
> @@ -2861,6 +2861,7 @@ static int igbvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>   	return 0;
>   
>   err_hw_init:
> +	netif_napi_del(&adapter->rx_ring->napi);
>   	kfree(adapter->tx_ring);
>   	kfree(adapter->rx_ring);
>   err_sw_init:
>