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- From c9b6668215a27f2346d5eedd6f29cc720985b448 Mon Sep 17 00:00:00 2001
- From: Jo-Philipp Wich <jo@mein.io>
- Date: Wed, 11 Sep 2019 21:09:59 +0200
- Subject: [PATCH] ustream-ssl: skip writing pending data if .eof is true after
- connect
- Check the .eof member of the underlying ustream after the call to
- __ustream_ssl_connect() since existing users of the library appear
- to set the eof flag as a way to signal connection termination upon
- failing certificate verification.
- This is a stop-gap measure to address TALOS-2019-0893 but a proper
- API redesign is required to give applications proper control over
- whether certificate failures are to be ignored or not and the default
- implementation without custom callbacks should always terminate on
- verification failures.
- Signed-off-by: Jo-Philipp Wich <jo@mein.io>
- ---
- ustream-ssl.c | 20 ++++++++++++++++++++
- 1 file changed, 20 insertions(+)
- diff --git a/ustream-ssl.c b/ustream-ssl.c
- index e6b084b..47f66d6 100644
- --- a/ustream-ssl.c
- +++ b/ustream-ssl.c
- @@ -40,6 +40,26 @@ static void ustream_ssl_check_conn(struct ustream_ssl *us)
- return;
-
- if (__ustream_ssl_connect(us) == U_SSL_OK) {
- +
- + /* __ustream_ssl_connect() will also return U_SSL_OK when certificate
- + * verification failed!
- + *
- + * Applications may register a custom .notify_verify_error callback in the
- + * struct ustream_ssl which is called upon verification failures, but there
- + * is no straight forward way for the callback to terminate the connection
- + * initiation right away, e.g. through a true or false return value.
- + *
- + * Instead, existing implementations appear to set .eof field of the underlying
- + * ustream in the hope that this inhibits further operations on the stream.
- + *
- + * Declare this informal behaviour "official" and check for the state of the
- + * .eof member after __ustream_ssl_connect() returned, and do not write the
- + * pending data if it is set to true.
- + */
- +
- + if (us->stream.eof)
- + return;
- +
- us->connected = true;
- if (us->notify_connected)
- us->notify_connected(us);
- --
- 2.20.1
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