tls: separate no-async decryption request handling from async

commit 41532b785e9d79636b3815a64ddf6a096647d011 upstream.

If we're not doing async, the handling is much simpler. There's no
reference counting, we just need to wait for the completion to wake us
up and return its result.

We should preferably also use a separate crypto_wait. I'm not seeing a
UAF as I did in the past, I think aec7961916f3 ("tls: fix race between
async notify and socket close") took care of it.

This will make the next fix easier.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/47bde5f649707610eaef9f0d679519966fc31061.1709132643.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ William: The original patch did not apply cleanly due to deletions of
  non-existent lines in 6.1.y. The UAF the author stopped seeing can still
  be reproduced on systems without AVX in conjunction with cryptd.
  Also removed an extraneous statement after a return statement that is
  adjacent to diff. ]
Link: https://lore.kernel.org/netdev/he2K1yz_u7bZ-CnYcTSQ4OxuLuHZXN6xZRgp6_ICSWnq8J5FpI_uD1i_1lTSf7WMrYb5ThiX1OR2GTOB2IltgT49Koy7Hhutr4du4KtLvyk=@willsroot.io/
Signed-off-by: William Liu <will@willsroot.io>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 6ac3dcbe87b5cb02a8a5e51485b2229ce71a29c4..e1e3207168e302c96baeb26940f830544997a656 100644 (file)
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -274,9 +274,15 @@ static int tls_do_decryption(struct sock *sk,
                DEBUG_NET_WARN_ON_ONCE(atomic_read(&ctx->decrypt_pending) < 1);
                atomic_inc(&ctx->decrypt_pending);
        } else {
+               DECLARE_CRYPTO_WAIT(wait);
+
                aead_request_set_callback(aead_req,
                                          CRYPTO_TFM_REQ_MAY_BACKLOG,
-                                         crypto_req_done, &ctx->async_wait);
+                                         crypto_req_done, &wait);
+               ret = crypto_aead_decrypt(aead_req);
+               if (ret == -EINPROGRESS || ret == -EBUSY)
+                       ret = crypto_wait_req(ret, &wait);
+               return ret;
        }
 
        ret = crypto_aead_decrypt(aead_req);
@@ -289,7 +295,6 @@ static int tls_do_decryption(struct sock *sk,
                /* all completions have run, we're not doing async anymore */
                darg->async = false;
                return ret;
-               ret = ret ?: -EINPROGRESS;
        }
 
        atomic_dec(&ctx->decrypt_pending);