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author | Jakub Kicinski <jakub.kicinski@netronome.com> | 2019-11-05 14:24:35 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2019-11-06 17:33:32 -0800 |
commit | 79ffe6087e9145d2377385cac48d0d6a6b4225a5 (patch) | |
tree | 7ad119676734db269b7ae127d3bf0908339306eb /net/tls/tls_main.c | |
parent | 02b1fa07bb58f5d1f349b5b09eb936739a7b20fc (diff) | |
download | linux-79ffe6087e9145d2377385cac48d0d6a6b4225a5.tar.bz2 |
net/tls: add a TX lock
TLS TX needs to release and re-acquire the socket lock if send buffer
fills up.
TLS SW TX path currently depends on only allowing one thread to enter
the function by the abuse of sk_write_pending. If another writer is
already waiting for memory no new ones are allowed in.
This has two problems:
- writers don't wake other threads up when they leave the kernel;
meaning that this scheme works for single extra thread (second
application thread or delayed work) because memory becoming
available will send a wake up request, but as Mallesham and
Pooja report with larger number of threads it leads to threads
being put to sleep indefinitely;
- the delayed work does not get _scheduled_ but it may _run_ when
other writers are present leading to crashes as writers don't
expect state to change under their feet (same records get pushed
and freed multiple times); it's hard to reliably bail from the
work, however, because the mere presence of a writer does not
guarantee that the writer will push pending records before exiting.
Ensuring wakeups always happen will make the code basically open
code a mutex. Just use a mutex.
The TLS HW TX path does not have any locking (not even the
sk_write_pending hack), yet it uses a per-socket sg_tx_data
array to push records.
Fixes: a42055e8d2c3 ("net/tls: Add support for async encryption of records for performance")
Reported-by: Mallesham Jatharakonda <mallesh537@gmail.com>
Reported-by: Pooja Trivedi <poojatrivedi@gmail.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tls/tls_main.c')
-rw-r--r-- | net/tls/tls_main.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c index ac88877dcade..0775ae40fcfb 100644 --- a/net/tls/tls_main.c +++ b/net/tls/tls_main.c @@ -267,6 +267,7 @@ void tls_ctx_free(struct sock *sk, struct tls_context *ctx) memzero_explicit(&ctx->crypto_send, sizeof(ctx->crypto_send)); memzero_explicit(&ctx->crypto_recv, sizeof(ctx->crypto_recv)); + mutex_destroy(&ctx->tx_lock); if (sk) kfree_rcu(ctx, rcu); @@ -612,6 +613,7 @@ static struct tls_context *create_ctx(struct sock *sk) if (!ctx) return NULL; + mutex_init(&ctx->tx_lock); rcu_assign_pointer(icsk->icsk_ulp_data, ctx); ctx->sk_proto = sk->sk_prot; return ctx; |