On Mon, Jul 22, 2019 at 02:26:34PM +0200, Arnd Bergmann wrote: > Building with clang and KASAN, we get a warning about an overly large > stack frame on 32-bit architectures: > > drivers/block/drbd/drbd_receiver.c:921:31: error: stack frame size of 1280 > bytes in function 'conn_connect' > [-Werror,-Wframe-larger-than=] > > We already allocate other data dynamically in this function, so > just do the same for the shash descriptor, which makes up most of > this memory. > > Link: https://lore.kernel.org/lkml/[email protected]/ > Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Kees Cook <[email protected]> -Kees > --- > v2: > - don't try to zero a NULL descriptor pointer, > based on review from Roland Kammerer. > --- > drivers/block/drbd/drbd_receiver.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/drivers/block/drbd/drbd_receiver.c > b/drivers/block/drbd/drbd_receiver.c > index 90ebfcae0ce6..2b3103c30857 100644 > --- a/drivers/block/drbd/drbd_receiver.c > +++ b/drivers/block/drbd/drbd_receiver.c > @@ -5417,7 +5417,7 @@ static int drbd_do_auth(struct drbd_connection > *connection) > unsigned int key_len; > char secret[SHARED_SECRET_MAX]; /* 64 byte */ > unsigned int resp_size; > - SHASH_DESC_ON_STACK(desc, connection->cram_hmac_tfm); > + struct shash_desc *desc; > struct packet_info pi; > struct net_conf *nc; > int err, rv; > @@ -5430,6 +5430,13 @@ static int drbd_do_auth(struct drbd_connection > *connection) > memcpy(secret, nc->shared_secret, key_len); > rcu_read_unlock(); > > + desc = kmalloc(sizeof(struct shash_desc) + > + crypto_shash_descsize(connection->cram_hmac_tfm), > + GFP_KERNEL); > + if (!desc) { > + rv = -1; > + goto fail; > + } > desc->tfm = connection->cram_hmac_tfm; > > rv = crypto_shash_setkey(connection->cram_hmac_tfm, (u8 *)secret, > key_len); > @@ -5571,7 +5578,10 @@ static int drbd_do_auth(struct drbd_connection > *connection) > kfree(peers_ch); > kfree(response); > kfree(right_response); > - shash_desc_zero(desc); > + if (desc) { > + shash_desc_zero(desc); > + kfree(desc); > + } > > return rv; > } > -- > 2.20.0 > -- Kees Cook
