[PATCH v2] net: tls: fix possible race condition between do_tls_getsockopt_conf() and do_tls_setsockopt_conf()

[Hangyu Hua]

ctx->crypto_send.info is not protected by lock_sock in
do_tls_getsockopt_conf(). A race condition between do_tls_getsockopt_conf()
and do_tls_setsockopt_conf() can cause a NULL point dereference or
use-after-free read when memcpy.

Please check the following link for pre-information:
 https://lore.kernel.org/all/Y/ht6gQL+u6fj3dG@hog/

Fixes: 3c4d7559159b ("tls: kernel TLS support")
Signed-off-by: Hangyu Hua <hbh25y@xxxxxxxxx>
---

	v2: Follow the advice of Jakub and lock do_tls_getsockopt()

 net/tls/tls_main.c | 23 +++++------------------
 1 file changed, 5 insertions(+), 18 deletions(-)

diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 3735cb00905d..b32c112984dd 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -405,13 +405,11 @@ static int do_tls_getsockopt_conf(struct sock *sk, char __user *optval,
 			rc = -EINVAL;
 			goto out;
 		}
-		lock_sock(sk);
 		memcpy(crypto_info_aes_gcm_128->iv,
 		       cctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
 		       TLS_CIPHER_AES_GCM_128_IV_SIZE);
 		memcpy(crypto_info_aes_gcm_128->rec_seq, cctx->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)))
@@ -429,13 +427,11 @@ static int do_tls_getsockopt_conf(struct sock *sk, char __user *optval,
 			rc = -EINVAL;
 			goto out;
 		}
-		lock_sock(sk);
 		memcpy(crypto_info_aes_gcm_256->iv,
 		       cctx->iv + TLS_CIPHER_AES_GCM_256_SALT_SIZE,
 		       TLS_CIPHER_AES_GCM_256_IV_SIZE);
 		memcpy(crypto_info_aes_gcm_256->rec_seq, cctx->rec_seq,
 		       TLS_CIPHER_AES_GCM_256_REC_SEQ_SIZE);
-		release_sock(sk);
 		if (copy_to_user(optval,
 				 crypto_info_aes_gcm_256,
 				 sizeof(*crypto_info_aes_gcm_256)))
@@ -451,13 +447,11 @@ static int do_tls_getsockopt_conf(struct sock *sk, char __user *optval,
 			rc = -EINVAL;
 			goto out;
 		}
-		lock_sock(sk);
 		memcpy(aes_ccm_128->iv,
 		       cctx->iv + TLS_CIPHER_AES_CCM_128_SALT_SIZE,
 		       TLS_CIPHER_AES_CCM_128_IV_SIZE);
 		memcpy(aes_ccm_128->rec_seq, cctx->rec_seq,
 		       TLS_CIPHER_AES_CCM_128_REC_SEQ_SIZE);
-		release_sock(sk);
 		if (copy_to_user(optval, aes_ccm_128, sizeof(*aes_ccm_128)))
 			rc = -EFAULT;
 		break;
@@ -472,13 +466,11 @@ static int do_tls_getsockopt_conf(struct sock *sk, char __user *optval,
 			rc = -EINVAL;
 			goto out;
 		}
-		lock_sock(sk);
 		memcpy(chacha20_poly1305->iv,
 		       cctx->iv + TLS_CIPHER_CHACHA20_POLY1305_SALT_SIZE,
 		       TLS_CIPHER_CHACHA20_POLY1305_IV_SIZE);
 		memcpy(chacha20_poly1305->rec_seq, cctx->rec_seq,
 		       TLS_CIPHER_CHACHA20_POLY1305_REC_SEQ_SIZE);
-		release_sock(sk);
 		if (copy_to_user(optval, chacha20_poly1305,
 				sizeof(*chacha20_poly1305)))
 			rc = -EFAULT;
@@ -493,13 +485,11 @@ static int do_tls_getsockopt_conf(struct sock *sk, char __user *optval,
 			rc = -EINVAL;
 			goto out;
 		}
-		lock_sock(sk);
 		memcpy(sm4_gcm_info->iv,
 		       cctx->iv + TLS_CIPHER_SM4_GCM_SALT_SIZE,
 		       TLS_CIPHER_SM4_GCM_IV_SIZE);
 		memcpy(sm4_gcm_info->rec_seq, cctx->rec_seq,
 		       TLS_CIPHER_SM4_GCM_REC_SEQ_SIZE);
-		release_sock(sk);
 		if (copy_to_user(optval, sm4_gcm_info, sizeof(*sm4_gcm_info)))
 			rc = -EFAULT;
 		break;
@@ -513,13 +503,11 @@ static int do_tls_getsockopt_conf(struct sock *sk, char __user *optval,
 			rc = -EINVAL;
 			goto out;
 		}
-		lock_sock(sk);
 		memcpy(sm4_ccm_info->iv,
 		       cctx->iv + TLS_CIPHER_SM4_CCM_SALT_SIZE,
 		       TLS_CIPHER_SM4_CCM_IV_SIZE);
 		memcpy(sm4_ccm_info->rec_seq, cctx->rec_seq,
 		       TLS_CIPHER_SM4_CCM_REC_SEQ_SIZE);
-		release_sock(sk);
 		if (copy_to_user(optval, sm4_ccm_info, sizeof(*sm4_ccm_info)))
 			rc = -EFAULT;
 		break;
@@ -535,13 +523,11 @@ static int do_tls_getsockopt_conf(struct sock *sk, char __user *optval,
 			rc = -EINVAL;
 			goto out;
 		}
-		lock_sock(sk);
 		memcpy(crypto_info_aria_gcm_128->iv,
 		       cctx->iv + TLS_CIPHER_ARIA_GCM_128_SALT_SIZE,
 		       TLS_CIPHER_ARIA_GCM_128_IV_SIZE);
 		memcpy(crypto_info_aria_gcm_128->rec_seq, cctx->rec_seq,
 		       TLS_CIPHER_ARIA_GCM_128_REC_SEQ_SIZE);
-		release_sock(sk);
 		if (copy_to_user(optval,
 				 crypto_info_aria_gcm_128,
 				 sizeof(*crypto_info_aria_gcm_128)))
@@ -559,13 +545,11 @@ static int do_tls_getsockopt_conf(struct sock *sk, char __user *optval,
 			rc = -EINVAL;
 			goto out;
 		}
-		lock_sock(sk);
 		memcpy(crypto_info_aria_gcm_256->iv,
 		       cctx->iv + TLS_CIPHER_ARIA_GCM_256_SALT_SIZE,
 		       TLS_CIPHER_ARIA_GCM_256_IV_SIZE);
 		memcpy(crypto_info_aria_gcm_256->rec_seq, cctx->rec_seq,
 		       TLS_CIPHER_ARIA_GCM_256_REC_SEQ_SIZE);
-		release_sock(sk);
 		if (copy_to_user(optval,
 				 crypto_info_aria_gcm_256,
 				 sizeof(*crypto_info_aria_gcm_256)))
@@ -614,11 +598,9 @@ static int do_tls_getsockopt_no_pad(struct sock *sk, char __user *optval,
 	if (len < sizeof(value))
 		return -EINVAL;
 
-	lock_sock(sk);
 	value = -EINVAL;
 	if (ctx->rx_conf == TLS_SW || ctx->rx_conf == TLS_HW)
 		value = ctx->rx_no_pad;
-	release_sock(sk);
 	if (value < 0)
 		return value;
 
@@ -635,6 +617,8 @@ static int do_tls_getsockopt(struct sock *sk, int optname,
 {
 	int rc = 0;
 
+	lock_sock(sk);
+
 	switch (optname) {
 	case TLS_TX:
 	case TLS_RX:
@@ -651,6 +635,9 @@ static int do_tls_getsockopt(struct sock *sk, int optname,
 		rc = -ENOPROTOOPT;
 		break;
 	}
+
+	release_sock(sk);
+
 	return rc;
 }
 
-- 
2.34.1