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Date: Fri, 05 Jan 2024 21:36:38 +0100
From: "Arnd Bergmann" <arnd@arndb.de>
To: "Keith Busch" <kbusch@kernel.org>, "Arnd Bergmann" <arnd@kernel.org>
Cc: "Christoph Hellwig" <hch@lst.de>, "Sagi Grimberg" <sagi@grimberg.me>,
 "Chaitanya Kulkarni" <kch@nvidia.com>, linux-nvme@lists.infradead.org,
 linux-kernel@vger.kernel.org, "Daniel Wagner" <dwagner@suse.de>,
 "Hannes Reinecke" <hare@suse.de>
Subject: Re: [PATCH 1/2] nvmet: re-fix tracing strncpy() warning
Content-Type: text/plain

On Fri, Jan 5, 2024, at 21:24, Keith Busch wrote:
> On Wed, Jan 03, 2024 at 04:56:55PM +0100, Arnd Bergmann wrote:
>> @@ -53,8 +53,7 @@ static inline void __assign_req_name(char *name, struct nvmet_req *req)
>>  		return;
>>  	}
>>  
>> -	strncpy(name, req->ns->device_path,
>> -		min_t(size_t, DISK_NAME_LEN, strlen(req->ns->device_path)));
>> +	strscpy_pad(name, req->ns->device_path, DISK_NAME_LEN);
>>  }
>
> I like this one, however Daniel has a different fix for this already
> staged in nvme-6.8:
>
>  
> https://git.infradead.org/nvme.git/commitdiff/8f6c0eec5fad13785fd53a5b3b5f8b97b722a2a3

+       snprintf(name,
+                min_t(size_t, DISK_NAME_LEN, strlen(req->ns->device_path) + 1),
+                "%s", req->ns->device_path);

Don't we still need the zero-padding here to avoid leaking
kernel data to userspace?

    Arnd