From: Tom Lendacky Subject: Re: [PATCH] crypto: hash.h: Prevent use of req->digest in ahash update Date: Tue, 6 Mar 2018 12:04:04 -0600 Message-ID: <0d5cfbd5-8675-290b-f840-d9121872f8da@amd.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , Bartlomiej Zolnierkiewicz , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org To: Kamil Konieczny , Herbert Xu Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On 3/6/2018 5:45 AM, Kamil Konieczny wrote: > Prevent improper use of req->digest field in ahash update, init, export and Shouldn't that be req->result (here and below)? Thanks, Tom > import functions in drivers code. A driver should use ahash request context > if it needs to save internal state. > > Signed-off-by: Kamil Konieczny > --- > include/crypto/hash.h | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/include/crypto/hash.h b/include/crypto/hash.h > index 2d1849dffb80..e97c2e662d6a 100644 > --- a/include/crypto/hash.h > +++ b/include/crypto/hash.h > @@ -74,7 +74,8 @@ struct ahash_request { > * @init: **[mandatory]** Initialize the transformation context. Intended only to initialize the > * state of the HASH transformation at the beginning. This shall fill in > * the internal structures used during the entire duration of the whole > - * transformation. No data processing happens at this point. > + * transformation. No data processing happens at this point. Driver code > + * implementation must not use req->digest. > * @update: **[mandatory]** Push a chunk of data into the driver for transformation. This > * function actually pushes blocks of data from upper layers into the > * driver, which then passes those to the hardware as seen fit. This > @@ -83,7 +84,8 @@ struct ahash_request { > * transformation. This function shall not modify the transformation > * context, as this function may be called in parallel with the same > * transformation object. Data processing can happen synchronously > - * [SHASH] or asynchronously [AHASH] at this point. > + * [SHASH] or asynchronously [AHASH] at this point. Driver must not use > + * req->digest. > * @final: **[mandatory]** Retrieve result from the driver. This function finalizes the > * transformation and retrieves the resulting hash from the driver and > * pushes it back to upper layers. No data processing happens at this > @@ -120,11 +122,12 @@ struct ahash_request { > * you want to save partial result of the transformation after > * processing certain amount of data and reload this partial result > * multiple times later on for multiple re-use. No data processing > - * happens at this point. > + * happens at this point. Driver must not use req->digest. > * @import: Import partial state of the transformation. This function loads the > * entire state of the ongoing transformation from a provided block of > * data so the transformation can continue from this point onward. No > - * data processing happens at this point. > + * data processing happens at this point. Driver must not use > + * req->digest. > * @halg: see struct hash_alg_common > */ > struct ahash_alg { >