tls_sw_recvmsg() and tls_decrypt_done() can be run concurrently.
consider the scenario tls_decrypt_done() is about to run complete()
and tls_sw_recvmsg() completed reinit_completion() then tls_decrypt_done()
runs complete(). This sequence of execution results in wrong
completion (ctx->async_wait.completion.done is 1 but it should
be 0). Consequently, for next decrypt request, it will not wait for
completion and on connection close crypto resources freed
(crypto_free_aead()), there is no way to handle pending decrypt
response.
This race condition can be avoided by having atomic_read()
(in tls_sw_recvmsg()) mutually exclusive with
atomic_dec_return(),complete() (in tls_decrypt_done()).
Intoduced spin lock to ensure the mutual exclution.
Addressed similar problem in tx direction.
Signed-off-by: Vinay Kumar Yadav <vinay.ya...@chelsio.com>
---
include/net/tls.h | 4 ++++
net/tls/tls_sw.c | 18 ++++++++++++++++--
2 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/include/net/tls.h b/include/net/tls.h
index bf9eb4823933..18cd4f418464 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -135,6 +135,8 @@ struct tls_sw_context_tx {
struct tls_rec *open_rec;
struct list_head tx_list;
atomic_t encrypt_pending;
+ /* protect crypto_wait with encrypt_pending */
+ spinlock_t encrypt_compl_lock;
int async_notify;
u8 async_capable:1;
@@ -155,6 +157,8 @@ struct tls_sw_context_rx {
u8 async_capable:1;
u8 decrypted:1;
atomic_t decrypt_pending;
+ /* protect crypto_wait with decrypt_pending*/
+ spinlock_t decrypt_compl_lock;
bool async_notify;
};
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index c98e602a1a2d..3f0446d38a16 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -206,10 +206,12 @@ static void tls_decrypt_done(struct crypto_async_request
*req, int err)
kfree(aead_req);
+ spin_lock_bh(&ctx->decrypt_compl_lock);
pending = atomic_dec_return(&ctx->decrypt_pending);
if (!pending && READ_ONCE(ctx->async_notify))
complete(&ctx->async_wait.completion);
+ spin_unlock_bh(&ctx->decrypt_compl_lock);
}
static int tls_do_decryption(struct sock *sk,
@@ -467,10 +469,12 @@ static void tls_encrypt_done(struct crypto_async_request
*req, int err)
ready = true;
}
+ spin_lock_bh(&ctx->encrypt_compl_lock);
pending = atomic_dec_return(&ctx->encrypt_pending);
if (!pending && READ_ONCE(ctx->async_notify))
complete(&ctx->async_wait.completion);
+ spin_unlock_bh(&ctx->encrypt_compl_lock);
if (!ready)
return;
@@ -924,6 +928,7 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg,
size_t size)
int num_zc = 0;
int orig_size;
int ret = 0;
+ int pending;
if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))
return -EOPNOTSUPP;
@@ -1092,7 +1097,10 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg,
size_t size)
/* Wait for pending encryptions to get completed */
smp_store_mb(ctx->async_notify, true);
- if (atomic_read(&ctx->encrypt_pending))
+ spin_lock_bh(&ctx->encrypt_compl_lock);
+ pending = atomic_read(&ctx->encrypt_pending);
+ spin_unlock_bh(&ctx->encrypt_compl_lock);
+ if (pending)
crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
else
reinit_completion(&ctx->async_wait.completion);
@@ -1727,6 +1735,7 @@ int tls_sw_recvmsg(struct sock *sk,
bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
bool is_peek = flags & MSG_PEEK;
int num_async = 0;
+ int pending;
flags |= nonblock;
@@ -1890,7 +1899,10 @@ int tls_sw_recvmsg(struct sock *sk,
if (num_async) {
/* Wait for all previously submitted records to be decrypted */
smp_store_mb(ctx->async_notify, true);
- if (atomic_read(&ctx->decrypt_pending)) {
+ spin_lock_bh(&ctx->decrypt_compl_lock);
+ pending = atomic_read(&ctx->decrypt_pending);
+ spin_unlock_bh(&ctx->decrypt_compl_lock);
+ if (pending) {
err = crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
if (err) {
/* one of async decrypt failed */
@@ -2287,6 +2299,7 @@ int tls_set_sw_offload(struct sock *sk, struct
tls_context *ctx, int tx)
if (tx) {
crypto_init_wait(&sw_ctx_tx->async_wait);
+ spin_lock_init(&sw_ctx_tx->encrypt_compl_lock);
crypto_info = &ctx->crypto_send.info;
cctx = &ctx->tx;
aead = &sw_ctx_tx->aead_send;
@@ -2295,6 +2308,7 @@ int tls_set_sw_offload(struct sock *sk, struct
tls_context *ctx, int tx)
sw_ctx_tx->tx_work.sk = sk;
} else {
crypto_init_wait(&sw_ctx_rx->async_wait);
+ spin_lock_init(&sw_ctx_rx->decrypt_compl_lock);
crypto_info = &ctx->crypto_recv.info;
cctx = &ctx->rx;
skb_queue_head_init(&sw_ctx_rx->rx_list);
--
2.18.1
