Hi Pascal, Quoting Pascal van Leeuwen (2020-09-08 08:10:45) > On systems with coherence issues, packet processed could succeed while > it should have failed, e.g. because of an authentication fail. > This is because the driver would read stale status information that had > all error bits initialised to zero = no error. > Since this is potential a security risk, we want to prevent it from being > a possibility at all. So initialize all error bits to error state, so > that reading stale status information will always result in errors. > > Signed-off-by: Pascal van Leeuwen <pvanleeuwen@xxxxxxxxxx> Acked-by: Antoine Tenart <antoine.tenart@xxxxxxxxxxx> Thanks! Antoine > --- > drivers/crypto/inside-secure/safexcel_ring.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/crypto/inside-secure/safexcel_ring.c b/drivers/crypto/inside-secure/safexcel_ring.c > index e454c3d..90f1503 100644 > --- a/drivers/crypto/inside-secure/safexcel_ring.c > +++ b/drivers/crypto/inside-secure/safexcel_ring.c > @@ -236,8 +236,8 @@ struct safexcel_result_desc *safexcel_add_rdesc(struct safexcel_crypto_priv *pri > > rdesc->particle_size = len; > rdesc->rsvd0 = 0; > - rdesc->descriptor_overflow = 0; > - rdesc->buffer_overflow = 0; > + rdesc->descriptor_overflow = 1; /* assume error */ > + rdesc->buffer_overflow = 1; /* assume error */ > rdesc->last_seg = last; > rdesc->first_seg = first; > rdesc->result_size = EIP197_RD64_RESULT_SIZE; > @@ -245,9 +245,10 @@ struct safexcel_result_desc *safexcel_add_rdesc(struct safexcel_crypto_priv *pri > rdesc->data_lo = lower_32_bits(data); > rdesc->data_hi = upper_32_bits(data); > > - /* Clear length & error code in result token */ > + /* Clear length in result token */ > rtoken->packet_length = 0; > - rtoken->error_code = 0; > + /* Assume errors - HW will clear if not the case */ > + rtoken->error_code = 0x7fff; > > return rdesc; > } > -- > 1.8.3.1 > -- Antoine Ténart, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
