Messages in this thread | | | Date | Mon, 27 Jan 2020 18:55:51 -0800 | From | Eric Biggers <> | Subject | Re: [RFC v3] crypto: ccree - protect against short scatterlists |
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On Mon, Jan 27, 2020 at 05:08:21PM +0200, Gilad Ben-Yossef wrote: > Deal gracefully with the event of being handed a scatterlist > which is shorter than expected. > > This mitigates a crash in some cases due to > attempt to map empty (but not NULL) scatterlists with none > zero lengths. > > Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com> > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
It's definitely wrong use of the crypto API to pass a scatterlist that's too short. Note that this is *not* what the test code is doing.
So I don't think you should be hacking around it here.
It is possible the bug is actually in cc_aead_chain_data()? It looks like it's adding the authentication tag size to the source data size for encryption, which is not correct. The authentication tag is part of the destination only.
size_for_map += (direct == DRV_CRYPTO_DIRECTION_ENCRYPT) ? authsize : 0; src_mapped_nents = cc_get_sgl_nents(dev, req->src, size_for_map, &src_last_bytes);
- Eric
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