From e414978bb06091697e96008f8500db4e86dc8b23 Mon Sep 17 00:00:00 2001
From: Artem Savkov <asavkov@redhat.com>
Date: Fri, 5 Nov 2021 15:13:50 +0100
Subject: [KPATCH CVE-2021-43267] tipc: fix size validations for the MSG_CRYPTO
 type

Kernels:
4.18.0-348.el8
4.18.0-348.1.1.el8_5

Changes since last build:
arches: x86_64 ppc64le
crypto.o: changed function: tipc_crypto_msg_rcv
---------------------------

Kpatch-MR: https://gitlab.com/redhat/prdsc/rhel/src/kpatch/rhel-8/-/merge_requests/7
Approved-by: Joe Lawrence (@joe.lawrence)
Kernels:
4.18.0-348.el8

Modifications: none

commit ff06de0480d0fdbdd6a3a9db663ffcd0297025c0
Author: Bruno Meneguele <bmeneg@redhat.com>
Date:   Fri Nov 5 10:38:28 2021 -0300

    tipc: fix size validations for the MSG_CRYPTO type

    Bugzilla: https://bugzilla.redhat.com/2020506
    CVE: CVE-2021-43267
    Y-Commit: fa40d9734a57bcbfa79a280189799f76c88f7bb0

    O-Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2020506
    O-CVE: CVE-2021-43267

    The function tipc_crypto_key_rcv is used to parse MSG_CRYPTO messages
    to receive keys from other nodes in the cluster in order to decrypt any
    further messages from them.
    This patch verifies that any supplied sizes in the message body are
    valid for the received message.

    Fixes: 1ef6f7c9390f ("tipc: add automatic session key exchange")
    Signed-off-by: Max VA <maxv@sentinelone.com>
    Acked-by: Ying Xue <ying.xue@windriver.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Acked-by: Jon Maloy <jmaloy@redhat.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    (cherry picked from commit fa40d9734a57bcbfa79a280189799f76c88f7bb0)
    Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>

Signed-off-by: Artem Savkov <asavkov@redhat.com>
---
 net/tipc/crypto.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
index 40ff244f2499..b4f8c0a234a0 100644
--- a/net/tipc/crypto.c
+++ b/net/tipc/crypto.c
@@ -2279,43 +2279,53 @@ static bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr)
 	u16 key_gen = msg_key_gen(hdr);
 	u16 size = msg_data_sz(hdr);
 	u8 *data = msg_data(hdr);
+	unsigned int keylen;
+
+	/* Verify whether the size can exist in the packet */
+	if (unlikely(size < sizeof(struct tipc_aead_key) + TIPC_AEAD_KEYLEN_MIN)) {
+		pr_debug("%s: message data size is too small\n", rx->name);
+		goto exit;
+	}
+
+	keylen = ntohl(*((__be32 *)(data + TIPC_AEAD_ALG_NAME)));
+
+	/* Verify the supplied size values */
+	if (unlikely(size != keylen + sizeof(struct tipc_aead_key) ||
+		     keylen > TIPC_AEAD_KEY_SIZE_MAX)) {
+		pr_debug("%s: invalid MSG_CRYPTO key size\n", rx->name);
+		goto exit;
+	}
 
 	spin_lock(&rx->lock);
 	if (unlikely(rx->skey || (key_gen == rx->key_gen && rx->key.keys))) {
 		pr_err("%s: key existed <%p>, gen %d vs %d\n", rx->name,
 		       rx->skey, key_gen, rx->key_gen);
-		goto exit;
+		goto exit_unlock;
 	}
 
 	/* Allocate memory for the key */
 	skey = kmalloc(size, GFP_ATOMIC);
 	if (unlikely(!skey)) {
 		pr_err("%s: unable to allocate memory for skey\n", rx->name);
-		goto exit;
+		goto exit_unlock;
 	}
 
 	/* Copy key from msg data */
-	skey->keylen = ntohl(*((__be32 *)(data + TIPC_AEAD_ALG_NAME)));
+	skey->keylen = keylen;
 	memcpy(skey->alg_name, data, TIPC_AEAD_ALG_NAME);
 	memcpy(skey->key, data + TIPC_AEAD_ALG_NAME + sizeof(__be32),
 	       skey->keylen);
 
-	/* Sanity check */
-	if (unlikely(size != tipc_aead_key_size(skey))) {
-		kfree(skey);
-		skey = NULL;
-		goto exit;
-	}
-
 	rx->key_gen = key_gen;
 	rx->skey_mode = msg_key_mode(hdr);
 	rx->skey = skey;
 	rx->nokey = 0;
 	mb(); /* for nokey flag */
 
-exit:
+exit_unlock:
 	spin_unlock(&rx->lock);
 
+exit:
 	/* Schedule the key attaching on this crypto */
 	if (likely(skey && queue_delayed_work(tx->wq, &rx->work, 0)))
 		return true;
-- 
2.31.1