Development discussion of WireGuard
 help / color / mirror / Atom feed
* [PATCH AUTOSEL 5.6 234/606] wireguard: noise: read preshared key while taking lock
       [not found] <20200608231211.3363633-1-sashal@kernel.org>
@ 2020-06-08 23:05 ` Sasha Levin
  0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2020-06-08 23:05 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Jason A. Donenfeld, Matt Dunwoodie, David S . Miller,
	Greg Kroah-Hartman, wireguard, netdev

From: "Jason A. Donenfeld" <Jason@zx2c4.com>

[ Upstream commit bc67d371256f5c47d824e2eec51e46c8d62d022e ]

Prior we read the preshared key after dropping the handshake lock, which
isn't an actual crypto issue if it races, but it's still not quite
correct. So copy that part of the state into a temporary like we do with
the rest of the handshake state variables. Then we can release the lock,
operate on the temporary, and zero it out at the end of the function. In
performance tests, the impact of this was entirely unnoticable, probably
because those bytes are coming from the same cacheline as other things
that are being copied out in the same manner.

Reported-by: Matt Dunwoodie <ncon@noconroy.net>
Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/wireguard/noise.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireguard/noise.c b/drivers/net/wireguard/noise.c
index 708dc61c974f..07eb438a6dee 100644
--- a/drivers/net/wireguard/noise.c
+++ b/drivers/net/wireguard/noise.c
@@ -715,6 +715,7 @@ wg_noise_handshake_consume_response(struct message_handshake_response *src,
 	u8 e[NOISE_PUBLIC_KEY_LEN];
 	u8 ephemeral_private[NOISE_PUBLIC_KEY_LEN];
 	u8 static_private[NOISE_PUBLIC_KEY_LEN];
+	u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN];
 
 	down_read(&wg->static_identity.lock);
 
@@ -733,6 +734,8 @@ wg_noise_handshake_consume_response(struct message_handshake_response *src,
 	memcpy(chaining_key, handshake->chaining_key, NOISE_HASH_LEN);
 	memcpy(ephemeral_private, handshake->ephemeral_private,
 	       NOISE_PUBLIC_KEY_LEN);
+	memcpy(preshared_key, handshake->preshared_key,
+	       NOISE_SYMMETRIC_KEY_LEN);
 	up_read(&handshake->lock);
 
 	if (state != HANDSHAKE_CREATED_INITIATION)
@@ -750,7 +753,7 @@ wg_noise_handshake_consume_response(struct message_handshake_response *src,
 		goto fail;
 
 	/* psk */
-	mix_psk(chaining_key, hash, key, handshake->preshared_key);
+	mix_psk(chaining_key, hash, key, preshared_key);
 
 	/* {} */
 	if (!message_decrypt(NULL, src->encrypted_nothing,
@@ -783,6 +786,7 @@ wg_noise_handshake_consume_response(struct message_handshake_response *src,
 	memzero_explicit(chaining_key, NOISE_HASH_LEN);
 	memzero_explicit(ephemeral_private, NOISE_PUBLIC_KEY_LEN);
 	memzero_explicit(static_private, NOISE_PUBLIC_KEY_LEN);
+	memzero_explicit(preshared_key, NOISE_SYMMETRIC_KEY_LEN);
 	up_read(&wg->static_identity.lock);
 	return ret_peer;
 }
-- 
2.25.1


^ permalink raw reply	[flat|nested] only message in thread

only message in thread, other threads:[~2020-06-08 23:17 UTC | newest]

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <20200608231211.3363633-1-sashal@kernel.org>
2020-06-08 23:05 ` [PATCH AUTOSEL 5.6 234/606] wireguard: noise: read preshared key while taking lock Sasha Levin

Development discussion of WireGuard

This inbox may be cloned and mirrored by anyone:

	git clone --mirror http://inbox.vuxu.org/wireguard

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V1 wireguard wireguard/ http://inbox.vuxu.org/wireguard \
		wireguard@lists.zx2c4.com
	public-inbox-index wireguard

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.vuxu.org/vuxu.archive.wireguard


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git