Commit 1c3b63f1 authored Aug 06, 2020 by Rouven Czerwinski Committed by David S. Miller Aug 07, 2020

net/tls: allow MSG_CMSG_COMPAT in sendmsg



Trying to use ktls on a system with 32-bit userspace and 64-bit kernel
results in a EOPNOTSUPP message during sendmsg:

  setsockopt(3, SOL_TLS, TLS_TX, …, 40) = 0
  sendmsg(3, …, msg_flags=0}, 0) = -1 EOPNOTSUPP (Operation not supported)

The tls_sw implementation does strict flag checking and does not allow
the MSG_CMSG_COMPAT flag, which is set if the message comes in through
the compat syscall.

This patch adds MSG_CMSG_COMPAT to the flag check to allow the usage of
the TLS SW implementation on systems using the compat syscall path.

Note that the same check is present in the sendmsg path for the TLS
device implementation, however the flag hasn't been added there for lack
of testing hardware.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 64cae2fb

net/tls/tls_sw.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -935,7 +935,8 @@ int tls_sw_sendmsg(struct sock sk, struct msghdr msg, size_t size)
		int ret = 0;
		int pending;

		if (msg->msg_flags & ~(MSG_MORE \| MSG_DONTWAIT \| MSG_NOSIGNAL))
		if (msg->msg_flags & ~(MSG_MORE \| MSG_DONTWAIT \| MSG_NOSIGNAL \|
		MSG_CMSG_COMPAT))
		return -EOPNOTSUPP;

		mutex_lock(&tls_ctx->tx_lock);

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