[PATCH 4.20 26/80] net: tls: Save iv in tls_rec for async crypto requests

Greg Kroah-Hartman
2019-02-04T10:53:23Z

From: Dave Watson <davejwatson@fb.com>

[ Upstream commit 32eb67b93c9e3cd62cb423e30b090cdd4aa8d275 ]

aead_request_set_crypt takes an iv pointer, and we change the iv
soon after setting it. Some async crypto algorithms don't save the iv,
so we need to save it in the tls_rec for async requests.

Found by hardcoding x64 aesni to use async crypto manager (to test the async
codepath), however I don't think this combination can happen in the wild.
Presumably other hardware offloads will need this fix, but there have been
no user reports.

Fixes: a42055e8d2c30 ("Add support for async encryption of records...")
Signed-off-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/tls.h | 2 ++
net/tls/tls_sw.c | 4 +++-
2 files changed, 5 insertions(+), 1 deletion(-)

--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -120,6 +120,8 @@ struct tls_rec {
struct scatterlist sg_aead_out[2];

char aad_space[TLS_AAD_SPACE_SIZE];
+ u8 iv_data[TLS_CIPHER_AES_GCM_128_IV_SIZE +
+ TLS_CIPHER_AES_GCM_128_SALT_SIZE];
struct aead_request aead_req;
u8 aead_req_ctx[];
};
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -439,6 +439,8 @@ static int tls_do_encryption(struct sock
struct scatterlist *sge = sk_msg_elem(msg_en, start);
int rc;

+ memcpy(rec->iv_data, tls_ctx->tx.iv, sizeof(rec->iv_data));
+
sge->offset += tls_ctx->tx.prepend_size;
sge->length -= tls_ctx->tx.prepend_size;

@@ -448,7 +450,7 @@ static int tls_do_encryption(struct sock
aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE);
aead_request_set_crypt(aead_req, rec->sg_aead_in,
rec->sg_aead_out,
- data_len, tls_ctx->tx.iv);
+ data_len, rec->iv_data);

aead_request_set_callback(aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
tls_encrypt_done, sk);