linux-kernel - Re: [PATCH] vfio/mlx5: fix possible overflow in tracking max

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <b68e4945-92cb-44f0-a364-2fe52520683a@nvidia.com>
Date: Tue, 1 Jul 2025 17:18:55 +0300
From: Yishai Hadas <yishaih@...dia.com>
To: Alex Williamson <alex.williamson@...hat.com>, Artem Sadovnikov
	<a.sadovnikov@...ras.ru>
CC: <kvm@...r.kernel.org>, Jason Gunthorpe <jgg@...pe.ca>, Shameer Kolothum
	<shameerali.kolothum.thodi@...wei.com>, Kevin Tian <kevin.tian@...el.com>,
	<linux-kernel@...r.kernel.org>, <lvc-project@...uxtesting.org>
Subject: Re: [PATCH] vfio/mlx5: fix possible overflow in tracking max

On 30/06/2025 20:28, Alex Williamson wrote:
> On Sun, 29 Jun 2025 09:58:43 +0000
> Artem Sadovnikov <a.sadovnikov@...ras.ru> wrote:
> 
>> MLX cap pg_track_log_max_msg_size consists of 5 bits, value of which is
>> used as power of 2 for max_msg_size. This can lead to multiplication
>> overflow between max_msg_size (u32) and integer constant, and afterwards
>> incorrect value is being written to rq_size.
>>
>> Fix this issue by extending max_msg_size up to u64 so multiplication will
>> be extended to u64.
> 
> Personally I'd go with changing the multiplier to 4ULL rather than
> changing the storage size here, but let's wait for Yishai and Jason.
> Thanks,
> 
> Alex
> 

Yes, let's go with Alex's suggestion.

max_msg_size based on the CAP, can't be larger than u32.

Yishai

>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>>
>> Signed-off-by: Artem Sadovnikov <a.sadovnikov@...ras.ru>
>> ---
>>   drivers/vfio/pci/mlx5/cmd.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
>> index 5b919a0b2524..0bdaf1d23a78 100644
>> --- a/drivers/vfio/pci/mlx5/cmd.c
>> +++ b/drivers/vfio/pci/mlx5/cmd.c
>> @@ -1503,7 +1503,7 @@ int mlx5vf_start_page_tracker(struct vfio_device *vdev,
>>   	struct mlx5_vhca_qp *fw_qp;
>>   	struct mlx5_core_dev *mdev;
>>   	u32 log_max_msg_size;
>> -	u32 max_msg_size;
>> +	u64 max_msg_size;
>>   	u64 rq_size = SZ_2M;
>>   	u32 max_recv_wr;
>>   	int err;
>