From 49c47cc21b5b7a3d8deb18fc57b0aa2ab1286962 Mon Sep 17 00:00:00 2001
From: Hangyu Hua <hbh25y@gmail.com>
Date: Fri, 12 May 2023 18:14:32 +0200
Subject: [PATCH] net: tls: fix possible race condition between
 do_tls_getsockopt_conf() and do_tls_setsockopt_conf()
Git-commit: 49c47cc21b5b7a3d8deb18fc57b0aa2ab1286962
Patch-mainline: v6.3-rc2
References: bsc#1209366 CVE-2023-28466

ctx->crypto_send.info is not protected by lock_sock in
do_tls_getsockopt_conf(). A race condition between do_tls_getsockopt_conf()
and error paths of do_tls_setsockopt_conf() may lead to a use-after-free
or null-deref.

More discussion:  https://lore.kernel.org/all/Y/ht6gQL+u6fj3dG@hog/

Fixes: 3c4d7559159b ("tls: kernel TLS support")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Link: https://lore.kernel.org/r/20230228023344.9623-1-hbh25y@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Vasant Karasulli <vkarasulli@suse.de>

---
 net/tls/tls_main.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index f88878b9a..3ff2d03f1 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -364,13 +364,11 @@ static int do_tls_getsockopt_tx(struct sock *sk, char __user *optval,
 			rc = -EINVAL;
 			goto out;
 		}
-		lock_sock(sk);
 		memcpy(crypto_info_aes_gcm_128->iv,
 		       ctx->tx.iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
 		       TLS_CIPHER_AES_GCM_128_IV_SIZE);
 		memcpy(crypto_info_aes_gcm_128->rec_seq, ctx->tx.rec_seq,
 		       TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE);
-		release_sock(sk);
 		if (copy_to_user(optval,
 				 crypto_info_aes_gcm_128,
 				 sizeof(*crypto_info_aes_gcm_128)))
@@ -390,6 +388,8 @@ static int do_tls_getsockopt(struct sock *sk, int optname,
 {
 	int rc = 0;

+	lock_sock(sk);
+
 	switch (optname) {
 	case TLS_TX:
 		rc = do_tls_getsockopt_tx(sk, optval, optlen);
@@ -398,6 +398,9 @@ static int do_tls_getsockopt(struct sock *sk, int optname,
 		rc = -ENOPROTOOPT;
 		break;
 	}
+
+	release_sock(sk);
+
 	return rc;
 }

--
2.34.1