tls_set_sw_offload() assigns ctx->push_pending_record for both directions, but the hook is a TX-side dispatcher. On a socket whose TX side is HW offloaded, tls_set_device_offload() installs tls_device_push_pending_record(); any later TLS_RX setsockopt overwrites it with tls_sw_push_pending_record(), because tls_set_device_offload_rx() itself calls tls_set_sw_offload(sk, 0, NULL) for the software half of a successful HW RX offload, and so does the fallback when the RX offload is declined (NIC with TX-only offload, tls_dev_add() failure). From then on tls_handle_open_record() (a TLS_SET_RECORD_TYPE cmsg after a MSG_MORE send, or the close path with a pending writer) runs tls_sw_push_pending_record() against priv_ctx_tx, which is a struct tls_offload_context_tx, not a struct tls_sw_context_tx, and reads open_rec from inside the offload context. On x86_64 without lock debugging that field overlays sg_tx_data[2].dma_address, which is never set, so the push is silently skipped and the data buffered by the MSG_MORE send is later sent under the cmsg's record type, e.g. application data in a handshake or alert record. Enabling CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_LOCK_ALLOC and CONFIG_LOCKDEP, but not CONFIG_LOCK_STAT, in the tested x86_64 configuration moves open_rec over sg_tx_data[5].page_link. Once populated, its page pointer and scatterlist flags are interpreted as a tls_rec pointer and dereferenced while reading msg_plaintext.sg.size. Only set the hook when initialising the TX side. Found by code review while developing TLS 1.3 HW offload rekey support. Tested with HW TLS TX and RX offload on Mellanox ConnectX-6 Dx (Crypto Enabled): after setting TLS_RX, send() "AAAA" with MSG_MORE, then sendmsg() "BBBB" with a TLS_SET_RECORD_TYPE cmsg for a handshake record. Without this patch the peer receives a single handshake record "AAAABBBB"; with it, an application data record "AAAA" followed by a handshake record "BBBB". Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Cc: stable@vger.kernel.org Signed-off-by: Rishikesh Jethwani --- net/tls/tls_sw.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index d1ad31986cf2..235b868facfa 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -2591,7 +2591,8 @@ int tls_set_sw_offload(struct sock *sk, int tx, } } - ctx->push_pending_record = tls_sw_push_pending_record; + if (tx) + ctx->push_pending_record = tls_sw_push_pending_record; /* setkey is the last operation that could fail during a * rekey. if it succeeds, we can start modifying the -- 2.50.1