tls: fix race between async notify and socket close
[ Upstream commit aec7961916f3f9e88766e2688992da6980f11b8d ]
The submitting thread (one which called recvmsg/sendmsg)
may exit as soon as the async crypto handler calls complete()
so any code past that point risks touching already freed data.
Try to avoid the locking and extra flags altogether.
Have the main thread hold an extra reference, this way
we can depend solely on the atomic ref counter for
synchronization.
Don't futz with reiniting the completion, either, we are now
tightly controlling when completion fires.
BUG=b/329957174
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-26583 in the Linux kernel.
Reported-by: valis <sec@valis.email>
Fixes: 0cada33241d9 ("net/tls: fix race condition causing kernel panic")
Change-Id: I5fdf76d54971a75f8bc8788c3d888379925b69d9
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/67297
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>
diff --git a/include/net/tls.h b/include/net/tls.h
index c36bf4c..899c863 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -108,9 +108,6 @@
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;
#define BIT_TX_SCHEDULED 0
@@ -147,8 +144,6 @@
struct tls_strparser strp;
atomic_t decrypt_pending;
- /* protect crypto_wait with decrypt_pending*/
- spinlock_t decrypt_compl_lock;
struct sk_buff_head async_hold;
struct wait_queue_head wq;
};
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 4e3a34b..d651c50 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -223,22 +223,15 @@
kfree(aead_req);
- spin_lock_bh(&ctx->decrypt_compl_lock);
- if (!atomic_dec_return(&ctx->decrypt_pending))
+ if (atomic_dec_and_test(&ctx->decrypt_pending))
complete(&ctx->async_wait.completion);
- spin_unlock_bh(&ctx->decrypt_compl_lock);
}
static int tls_decrypt_async_wait(struct tls_sw_context_rx *ctx)
{
- int pending;
-
- spin_lock_bh(&ctx->decrypt_compl_lock);
- reinit_completion(&ctx->async_wait.completion);
- pending = atomic_read(&ctx->decrypt_pending);
- spin_unlock_bh(&ctx->decrypt_compl_lock);
- if (pending)
+ if (!atomic_dec_and_test(&ctx->decrypt_pending))
crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
+ atomic_inc(&ctx->decrypt_pending);
return ctx->async_wait.err;
}
@@ -266,6 +259,7 @@
aead_request_set_callback(aead_req,
CRYPTO_TFM_REQ_MAY_BACKLOG,
tls_decrypt_done, aead_req);
+ DEBUG_NET_WARN_ON_ONCE(atomic_read(&ctx->decrypt_pending) < 1);
atomic_inc(&ctx->decrypt_pending);
} else {
aead_request_set_callback(aead_req,
@@ -455,7 +449,6 @@
struct tls_rec *rec;
bool ready = false;
struct sock *sk;
- int pending;
rec = container_of(aead_req, struct tls_rec, aead_req);
msg_en = &rec->msg_encrypted;
@@ -495,12 +488,8 @@
ready = true;
}
- spin_lock_bh(&ctx->encrypt_compl_lock);
- pending = atomic_dec_return(&ctx->encrypt_pending);
-
- if (!pending && ctx->async_notify)
+ if (atomic_dec_and_test(&ctx->encrypt_pending))
complete(&ctx->async_wait.completion);
- spin_unlock_bh(&ctx->encrypt_compl_lock);
if (!ready)
return;
@@ -512,22 +501,9 @@
static int tls_encrypt_async_wait(struct tls_sw_context_tx *ctx)
{
- int pending;
-
- spin_lock_bh(&ctx->encrypt_compl_lock);
- ctx->async_notify = true;
-
- pending = atomic_read(&ctx->encrypt_pending);
- spin_unlock_bh(&ctx->encrypt_compl_lock);
- if (pending)
+ if (!atomic_dec_and_test(&ctx->encrypt_pending))
crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
- else
- reinit_completion(&ctx->async_wait.completion);
-
- /* There can be no concurrent accesses, since we have no
- * pending encrypt operations
- */
- WRITE_ONCE(ctx->async_notify, false);
+ atomic_inc(&ctx->encrypt_pending);
return ctx->async_wait.err;
}
@@ -578,6 +554,7 @@
/* Add the record in tx_list */
list_add_tail((struct list_head *)&rec->list, &ctx->tx_list);
+ DEBUG_NET_WARN_ON_ONCE(atomic_read(&ctx->encrypt_pending) < 1);
atomic_inc(&ctx->encrypt_pending);
rc = crypto_aead_encrypt(aead_req);
@@ -2595,7 +2572,7 @@
}
crypto_init_wait(&sw_ctx_tx->async_wait);
- spin_lock_init(&sw_ctx_tx->encrypt_compl_lock);
+ atomic_set(&sw_ctx_tx->encrypt_pending, 1);
INIT_LIST_HEAD(&sw_ctx_tx->tx_list);
INIT_DELAYED_WORK(&sw_ctx_tx->tx_work.work, tx_work_handler);
sw_ctx_tx->tx_work.sk = sk;
@@ -2616,7 +2593,7 @@
}
crypto_init_wait(&sw_ctx_rx->async_wait);
- spin_lock_init(&sw_ctx_rx->decrypt_compl_lock);
+ atomic_set(&sw_ctx_rx->decrypt_pending, 1);
init_waitqueue_head(&sw_ctx_rx->wq);
skb_queue_head_init(&sw_ctx_rx->rx_list);
skb_queue_head_init(&sw_ctx_rx->async_hold);
