Set SSL_OP_LEGACY_SERVER_CONNECT when peeking at servers (#2354) #2355
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…#2354) Our TLS Server Hello parser does not treat legacy servers specially, but enabling legacy server support in OpenSSL allows OpenSSL to advance enough in its Server Hello processing to provide our SslBump code with the server certificate (that we then validate). Successful certificate validation, in turn, may result in Squid splicing the connection, even if OpenSSL detected other errors: noteNegotiationError: hold TLS write on FD 15 despite SQUID_TLS_ERR_CONNECT+TLS_LIB_ERR=2000068+TLS_IO_ERR=1 A spliced connection allows the TLS client to handle a legacy server the way the client needs to handle it, without unwanted Squid meddling. This is a Measurement Factory project.
yadij
approved these changes
Jan 16, 2026
kinkie
approved these changes
Jan 17, 2026
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Our TLS Server Hello parser does not treat legacy servers specially, but
enabling legacy server support in OpenSSL allows OpenSSL to advance
enough in its Server Hello processing to provide our SslBump code with
the server certificate (that we then validate). Successful certificate
validation, in turn, may result in Squid splicing the connection, even
if OpenSSL detected other errors:
A spliced connection allows the TLS client to handle a legacy server the
way the client needs to handle it, without unwanted Squid meddling.
This is a Measurement Factory project.