Re: copy on write for splice() from file to pipe?

On Fri, Feb 17, 2023 at 03:13:14PM -0800, Andy Lutomirski wrote:

I can certainly imagine TLS or similar protocols breaking if data
changes if the implementation is too clever and retransmission
happens.  Suppose 2000 bytes are sent via splice using in-kernel TLS,
and it goes out on the wire as two TCP segments.  The first segment is
dropped but the second is received.  The kernel resends the first
segment using different data.  This really ought to cause an integrity
check at the far end to fail.

The TLS layer is completely separate from TCP so it's like any
normal TCP user from user-space.  IOW the encrypted data will be
held by TCP until acknowledged so during retransmission it will
simply resend the previously encrypted data rather than encrypting
the same data twice.

Cheers,
-- 
Email: Herbert Xu [off-list ref]
Home Page: http://gondor.apana.org.au/~herbert/
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