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Commit 38c919ec authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Greg Kroah-Hartman
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drbd: dynamically allocate shash descriptor 

[ Upstream commit 77ce56e2bfaa64127ae5e23ef136c0168b818777 ]

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/20190617132440.2721536-1-arnd@arndb.de/


Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarRoland Kammerer <roland.kammerer@linbit.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent f4e2d182

drivers/block/drbd/drbd_receiver.c

+12 −2
Original line number Diff line number Diff line
@@ -5240,7 +5240,7 @@ 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;
@@ -5253,6 +5253,13 @@ 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;

	desc->flags = 0;
@@ -5395,7 +5402,10 @@ static int drbd_do_auth(struct drbd_connection *connection) 
	kfree(peers_ch);

	kfree(response);

	kfree(right_response);

	if (desc) {

		shash_desc_zero(desc);

		kfree(desc);

	}



	return rv;

}