Re: [PATCH] net: arcnet: com20020: Fix null-ptr-deref in com20020pci_probe()

From: Jakub Kicinski
Date: Tue Mar 01 2022 - 21:29:02 EST


On Mon, 28 Feb 2022 11:44:13 +0000 Zheyu Ma wrote:
> During driver initialization, the pointer of card info, i.e. the
> variable 'ci' is required. However, the definition of
> 'com20020pci_id_table' reveals that this field is empty for some
> devices, which will cause null pointer dereference when initializing
> these devices.
>
> The following log reveals it:
>
> [ 3.973806] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
> [ 3.973819] RIP: 0010:com20020pci_probe+0x18d/0x13e0 [com20020_pci]
> [ 3.975181] Call Trace:
> [ 3.976208] local_pci_probe+0x13f/0x210
> [ 3.977248] pci_device_probe+0x34c/0x6d0
> [ 3.977255] ? pci_uevent+0x470/0x470
> [ 3.978265] really_probe+0x24c/0x8d0
> [ 3.978273] __driver_probe_device+0x1b3/0x280
> [ 3.979288] driver_probe_device+0x50/0x370
>
> Fix this by checking whether the 'ci' is a null pointer first.

Can we get a Fixes tag pointing to the commit where the problem was
introduced?