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Subject: Re: [PATCH] proc: use vmalloc for our kernel buffer
To:     Matthew Wilcox <willy@infradead.org>
Cc:     hch@lst.de, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-team@fb.com
References: <20200813145305.805730-1-josef@toxicpanda.com>
 <20200813145941.GJ17456@casper.infradead.org>
From:   Josef Bacik <josef@toxicpanda.com>
Message-ID: <3fad71b2-eda1-aca4-f421-41d2097e4769@toxicpanda.com>
Date:   Thu, 13 Aug 2020 11:08:41 -0400
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On 8/13/20 10:59 AM, Matthew Wilcox wrote:
> On Thu, Aug 13, 2020 at 10:53:05AM -0400, Josef Bacik wrote:
>> +/**
>> + * vmemdup_user - duplicate memory region from user space and NUL-terminate
> 
> vmemdup_user_nul()
> 
>> +void *vmemdup_user_nul(const void __user *src, size_t len)
>> +{
>> +	void *p;
>> +
>> +	p = kvmalloc(len, GFP_USER);
> 
> len+1, shirley?
> 
>> +	if (!p)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	if (copy_from_user(p, src, len)) {
>> +		kvfree(p);
>> +		return ERR_PTR(-EFAULT);
>> +	}
> 
> I think you forgot
> 
>          p[len] = '\0';
> 

Sweet lord I need more sleep, my bad.  Thanks,

Josef