RE: [PATCH] net/mlx5: fix use after free when releasing tx queues

[Dariusz Sosnowski <dsosnowski@nvidia.com>]

Hi,

> -----Original Message-----
> From: Yunjian Wang <wangyunjian@huawei.com>
> Sent: Tuesday, February 20, 2024 10:32
> To: dev@dpdk.org
> Cc: Dariusz Sosnowski <dsosnowski@nvidia.com>; Ori Kam
> <orika@nvidia.com>; Matan Azrad <matan@nvidia.com>; Slava Ovsiienko
> <viacheslavo@nvidia.com>; Suanming Mou <suanmingm@nvidia.com>;
> luyicai@huawei.com; Pengfei Sun <sunpengfei16@huawei.com>;
> stable@dpdk.org
> Subject: [PATCH] net/mlx5: fix use after free when releasing tx queues
> 
> From: Pengfei Sun <sunpengfei16@huawei.com>
> 
> In function mlx5_dev_configure, dev->data->tx_queues is assigned to priv-
> >txqs. When a member is removed from a bond, the function
> eth_dev_tx_queue_config is called to release dev->data->tx_queues.
> However, function mlx5_dev_close will access priv->txqs again and cause the
> use after free problem.
> 
> In function mlx5_dev_close, before free priv->txqs, we add a check that dev-
> >data->tx_queues is not NULL.
> 
> build/app/dpdk-testpmd -c7 -a 0000:08:00.2 --  -i --nb-cores=2
> --total-num-mbufs=2048
> 
> testpmd> port stop 0
> testpmd> create bonding device 4 0
> testpmd> add bonding member 0 1
> testpmd> remove bonding member 0 1
> testpmd> quit
> 
> ASan reports:
> ==2571911==ERROR: AddressSanitizer: heap-use-after-free on address
> 0x000174529880 at pc 0x0000113c8440 bp 0xffffefae0ea0 sp 0xffffefae0eb0
> READ of size 8 at 0x000174529880 thread T0
>     #0 0x113c843c in mlx5_txq_release ../drivers/net/mlx5/mlx5_txq.c:
> 1203
>     #1 0xffdb53c in mlx5_dev_close ../drivers/net/mlx5/mlx5.c:2286
>     #2 0xe12dc0 in rte_eth_dev_close ../lib/ethdev/rte_ethdev.c:1877
>     #3 0x6bac1c in close_port ../app/test-pmd/testpmd.c:3540
>     #4 0x6bc320 in pmd_test_exit ../app/test-pmd/testpmd.c:3808
>     #5 0x6c1a94 in main ../app/test-pmd/testpmd.c:4759
>     #6 0xffff9328f038  (/usr/lib64/libc.so.6+0x2b038)
>     #7 0xffff9328f110 in __libc_start_main (/usr/lib64/libc.so.6+
> 0x2b110)
> 
> Fixes: 6e78005 ("net/mlx5: add reference counter on DPDK Tx queues")
> Cc: stable@dpdk.org
> 
> Reported-by: Yunjian Wang <wangyunjian@huawei.com>
> Signed-off-by: Pengfei Sun <sunpengfei16@huawei.com>
Acked-by: Dariusz Sosnowski <dsosnowski@nvidia.com>

Thank you for the patch.

Question to ethdev maintainers:

While reviewing this patch, I took a look at rte_eth_dev_internal_reset() which is called by bonding PMD for removed members.
This resets Rx and Tx queue configuration, and dev->data->dev_conf,
but not dev->data->dev_configured flag.
So theoretically, after this call, a port can be started without port configuration, which seems invalid.
What do you think? Should it be fixed? 

Best regards,
Dariusz Sosnowski