Acked-by: Mikhail Zaslonko <zaslonko@xxxxxxxxxxxxx>
Please, also add:
Cc: <stable@xxxxxxxxxxxxxxx> # 5.6
On 15.12.2020 16:55, Ilya Leoshkevich wrote:
> Decompressing zlib streams on s390 fails with "incorrect data check"
> error.
>
> Userspace zlib checks inflate_state.flags in order to byteswap checksums
> only for zlib streams, and s390 hardware inflate code, which was ported
> from there, tries to match this behavior. At the same time, kernel zlib
> does not use inflate_state.flags, so it contains essentially random
> values. For many use cases either zlib stream is zeroed out or checksum
> is not used, so this problem is masked, but at least SquashFS is still
> affected.
>
> Fix by always passing a checksum to and from the hardware as is, which
> matches zlib_inflate()'s expectations.
>
> Fixes: 126196100063 ("lib/zlib: add s390 hardware support for kernel zlib_inflate")
> Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
> ---
> lib/zlib_dfltcc/dfltcc_inflate.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/zlib_dfltcc/dfltcc_inflate.c b/lib/zlib_dfltcc/dfltcc_inflate.c
> index db107016d29b..fb60b5a6a1cb 100644
> --- a/lib/zlib_dfltcc/dfltcc_inflate.c
> +++ b/lib/zlib_dfltcc/dfltcc_inflate.c
> @@ -125,7 +125,7 @@ dfltcc_inflate_action dfltcc_inflate(
> param->ho = (state->write - state->whave) & ((1 << HB_BITS) - 1);
> if (param->hl)
> param->nt = 0; /* Honor history for the first block */
> - param->cv = state->flags ? REVERSE(state->check) : state->check;
> + param->cv = state->check;
>
> /* Inflate */
> do {
> @@ -138,7 +138,7 @@ dfltcc_inflate_action dfltcc_inflate(
> state->bits = param->sbb;
> state->whave = param->hl;
> state->write = (param->ho + param->hl) & ((1 << HB_BITS) - 1);
> - state->check = state->flags ? REVERSE(param->cv) : param->cv;
> + state->check = param->cv;
> if (cc == DFLTCC_CC_OP2_CORRUPT && param->oesc != 0) {
> /* Report an error if stream is corrupted */
> state->mode = BAD;
>
