[PATCH 44/64] cachefiles: Implement key to filename encoding

David Howells dhowells at redhat.com
Wed Dec 1 00:29:25 PST 2021


JeffleXu <jefflexu at linux.alibaba.com> wrote:

> > +	/* If the path is usable ASCII, then we render it directly */
> > +	if (print) {
> > +		len = 1 + keylen + 1;
> > +		name = kmalloc(len, GFP_KERNEL);
> > +		if (!name)
> > +			return false;
> > +
> > +		name[0] = 'D'; /* Data object type, string encoding */
> > +		name[1 + keylen] = 0;
> > +		memcpy(name + 1, key, keylen);
> > +		goto success;
> 			^
> If we goto success from here,
> ...
> > +
> > +success:
> > +	name[len] = 0;
> 	     ^
> then it seems that this will cause an out-of-boundary access.

You're right.  I'll change that to:

		len = 1 + keylen;
		name = kmalloc(len + 1, GFP_KERNEL);

and I shouldn't need:

		name[1 + keylen] = 0;

as that's also done after the success label.

David




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