Re: [PATCH] crypto: nx-sha256/512: respect sg limit bounds when building sg lists

From: Herbert Xu
Date: Tue Aug 11 2015 - 10:06:23 EST

On Sat, Aug 08, 2015 at 08:47:28AM +0200, Jan Stancek wrote:
> Commit 000851119e80 changed sha256/512 update functions to
> pass more data to nx_build_sg_list(), which ends with
> sg list overflows and usually with update functions failing
> for data larger than max_sg_len * NX_PAGE_SIZE.
> This happens because:
> - both "total" and "to_process" are updated, which leads to
> "to_process" getting overflowed for some data lengths
> For example:
> In first iteration "total" is 50, and let's assume "to_process"
> is 30 due to sg limits. At the end of first iteration "total" is
> set to 20. At start of 2nd iteration "to_process" overflows on:
> to_process = total - to_process;
> - "in_sg" is not reset to nx_ctx->in_sg after each iteration
> - nx_build_sg_list() is hitting overflow because the amount of data
> passed to it would require more than sgmax elements
> - as consequence of previous item, data stored in overflowed sg list
> may no longer be aligned to SHA*_BLOCK_SIZE
> This patch changes sha256/512 update functions so that "to_process"
> respects sg limits and never tries to pass more data to
> nx_build_sg_list() to avoid overflows. "to_process" is calculated
> as minimum of "total" and sg limits at start of every iteration.
> Fixes: 000851119e80 ("crypto: nx - Fix SHA concurrence issue and sg
> limit bounds")
> Signed-off-by: Jan Stancek <jstancek@xxxxxxxxxx>
> Cc: Leonidas Da Silva Barbosa <leosilva@xxxxxxxxxxxxxxxxxx>
> Cc: Marcelo Henrique Cerri <mhcerri@xxxxxxxxxxxxxxxxxx>
> Cc: Fionnuala Gunter <fin@xxxxxxxxxxxxxxxxxx>
> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>

Patch applied with stable cc. Thanks a lot!
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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