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UPSTREAM: tls: fix race between async notify and socket close

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[ 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: 326214245
Reported-by: valis <sec@valis.email>
Fixes: 0cada33241 ("net/tls: fix race condition causing kernel panic")
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>
(cherry picked from commit 7a3ca06d04d589deec81f56229a9a9d62352ce01)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Idda32dd68ed26ae5c85c985305f52c3b2245e32c
This commit is contained in:
Jakub Kicinski 2024-02-06 17:18:19 -08:00 committed by Lee Jones
parent fd16669b18
commit 5b4439c0d7
2 changed files with 10 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/net/tls.h
View File

@ -109,9 +109,6 @@ 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;
#define BIT_TX_SCHEDULED 0
@ -150,8 +147,6 @@ struct tls_sw_context_rx {
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;

43
net/tls/tls_sw.c
View File

@ -223,22 +223,15 @@ static void tls_decrypt_done(crypto_completion_data_t *data, int err)
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 @@ static int tls_do_decryption(struct sock *sk,
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 @@ static void tls_encrypt_done(crypto_completion_data_t *data, int err)
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 @@ static void tls_encrypt_done(crypto_completion_data_t *data, int err)
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 void tls_encrypt_done(crypto_completion_data_t *data, int err)
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 @@ static int tls_do_encryption(struct sock *sk,
/* 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);
@ -2530,7 +2507,7 @@ static struct tls_sw_context_tx *init_ctx_tx(struct tls_context *ctx, struct soc
}
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;
@ -2551,7 +2528,7 @@ static struct tls_sw_context_rx *init_ctx_rx(struct tls_context *ctx)
}
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);