[PATCH v2 net-next 05/12] tls: Avoid copying crypto_info again after cipher_type check.
flat view
STALE3275d
SUPERSEDED
From: Ilya Lesokhin <hidden>
Date: 2017-11-08 13:38:58
Subsystem:
networking [general], networking [tls], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, John Fastabend, Sabrina Dubroca, Linus Torvalds
Status: Superseded by v3 (posted 2017-12-18). [go to v3]
Revision v2 (3 revisions archived).
Revisions (3)
- v1
- v2 current [diff against previous]
- v3 [diff against previous]
Avoid copying crypto_info again after cipher_type check
to avoid a TOCTOU exploits.
The temporary array on the stack is removed as we don't really need it
Fixes: 3c4d7559159b ('tls: kernel TLS support')
Signed-off-by: Ilya Lesokhin <redacted>
---
net/tls/tls_main.c | 29 ++++++++++++-----------------
1 file changed, 12 insertions(+), 17 deletions(-)
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 13427ee..ab1bd16 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c@@ -355,7 +355,7 @@ static int tls_getsockopt(struct sock *sk, int level, int optname, static int do_tls_setsockopt_tx(struct sock *sk, char __user *optval, unsigned int optlen) { - struct tls_crypto_info *crypto_info, tmp_crypto_info; + struct tls_crypto_info *crypto_info; struct tls_context *ctx = tls_get_ctx(sk); int rc = 0; int tx_conf;
@@ -365,36 +365,31 @@ static int do_tls_setsockopt_tx(struct sock *sk, char __user *optval, goto out; } - rc = copy_from_user(&tmp_crypto_info, optval, sizeof(*crypto_info)); + crypto_info = &ctx->crypto_send; + /* Currently we don't support set crypto info more than one time */ + if (TLS_CRYPTO_INFO_READY(crypto_info)) + goto out; + + rc = copy_from_user(crypto_info, optval, sizeof(*crypto_info)); if (rc) { rc = -EFAULT; goto out; } /* check version */ - if (tmp_crypto_info.version != TLS_1_2_VERSION) { + if (crypto_info->version != TLS_1_2_VERSION) { rc = -ENOTSUPP; - goto out; + goto err_crypto_info; } - /* get user crypto info */ - crypto_info = &ctx->crypto_send; - - /* Currently we don't support set crypto info more than one time */ - if (TLS_CRYPTO_INFO_READY(crypto_info)) - goto out; - - switch (tmp_crypto_info.cipher_type) { + switch (crypto_info->cipher_type) { case TLS_CIPHER_AES_GCM_128: { if (optlen != sizeof(struct tls12_crypto_info_aes_gcm_128)) { rc = -EINVAL; goto out; } - rc = copy_from_user( - crypto_info, - optval, - sizeof(struct tls12_crypto_info_aes_gcm_128)); - + rc = copy_from_user(crypto_info + 1, optval + sizeof(*crypto_info), + optlen - sizeof(*crypto_info)); if (rc) { rc = -EFAULT; goto err_crypto_info;
--
1.8.3.1