* bug#34102: [staging] Guix fails to download from TLSv1.3-enabled servers
2019-01-16 13:33 bug#34102: [staging] Guix fails to download from TLSv1.3-enabled servers Marius Bakke
@ 2019-01-25 13:43 ` Ludovic Courtès
2019-01-25 14:04 ` Ricardo Wurmus
2019-06-12 12:34 ` Ludovic Courtès
1 sibling, 1 reply; 6+ messages in thread
From: Ludovic Courtès @ 2019-01-25 13:43 UTC (permalink / raw)
To: Marius Bakke; +Cc: 34102
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Hi Marius,
Marius Bakke <mbakke@fastmail.com> skribis:
> On the staging branch (with GnuTLS 3.6), `guix download` will negotiate
> TLSv1.3 with servers that support it, and fail shortly after the initial
> handshake:
>
> $ ./pre-inst-env guix download https://data.iana.org
> Starting download of /tmp/guix-file.vJ4v7h
> From https://data.iana.org...
> Throw to key `gnutls-error' with args `(#<gnutls-error-enum Resource temporarily unavailable, try again.> read_from_session_record_port)'.
> failed to download "/tmp/guix-file.vJ4v7h" from "https://data.iana.org"
> guix download: error: https://data.iana.org: download failed
Ouch, thanks for the heads-up!
> The GnuTLS maintainer have written a blog post about TLS 1.3 porting[0],
> and I suspect the problem is that Guix (or the GnuTLS Guile bindings)
> does not handle the "GNUTLS_E_REAUTH_REQUEST" error code; however my
> attempts at catching it (or any error code) has been unfruitful.
I think we need to update the Guile bindings to wrap
GNUTLS_E_REAUTH_REQUEST, GNUTLS_POST_HANDSHAKE_AUTH, and
‘gnutls_reauth’, which are currently missing. Would you like to give it
a try?
What’s unclear to me from the blog post is exactly when
GNUTLS_E_REAUTH_REQUEST is delivered to the application. Is it the next
time the application calls some (possibly unrelated) GnuTLS function?
> This is an obvious merge blocker, help wanted! Disabling TLS1.3 in the
> priority string works as a last-resort workaround.
Yes, that’s a stop-gap measure we should probably apply for now:
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
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diff --git a/guix/build/download.scm b/guix/build/download.scm
index c08221b3b2..23c9a4d466 100644
--- a/guix/build/download.scm
+++ b/guix/build/download.scm
@@ -268,7 +268,10 @@ host name without trailing dot."
;; "(gnutls) Priority Strings"); see <http://bugs.gnu.org/23311>.
;; Explicitly disable SSLv3, which is insecure:
;; <https://tools.ietf.org/html/rfc7568>.
- (set-session-priorities! session "NORMAL:%COMPAT:-VERS-SSL3.0")
+ ;;
+ ;; FIXME: Since we currently fail to handle TLS 1.3, remove it; see
+ ;; <https://bugs.gnu.org/34102>.
+ (set-session-priorities! session "NORMAL:%COMPAT:-VERS-SSL3.0:-VERS-TLS1.3")
(set-session-credentials! session
(if (and verify-certificate? ca-certs)
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Any objections?
Thanks,
Ludo’.
^ permalink raw reply related [flat|nested] 6+ messages in thread* bug#34102: [staging] Guix fails to download from TLSv1.3-enabled servers
2019-01-16 13:33 bug#34102: [staging] Guix fails to download from TLSv1.3-enabled servers Marius Bakke
2019-01-25 13:43 ` Ludovic Courtès
@ 2019-06-12 12:34 ` Ludovic Courtès
2020-03-27 8:07 ` Ludovic Courtès
1 sibling, 1 reply; 6+ messages in thread
From: Ludovic Courtès @ 2019-06-12 12:34 UTC (permalink / raw)
To: Marius Bakke; +Cc: 34102
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Hi Marius,
Marius Bakke <mbakke@fastmail.com> skribis:
> $ ./pre-inst-env guix download https://data.iana.org
> Starting download of /tmp/guix-file.vJ4v7h
> From https://data.iana.org...
> Throw to key `gnutls-error' with args `(#<gnutls-error-enum Resource temporarily unavailable, try again.> read_from_session_record_port)'.
> failed to download "/tmp/guix-file.vJ4v7h" from "https://data.iana.org"
> guix download: error: https://data.iana.org: download failed
>
> The GnuTLS maintainer have written a blog post about TLS 1.3 porting[0],
> and I suspect the problem is that Guix (or the GnuTLS Guile bindings)
> does not handle the "GNUTLS_E_REAUTH_REQUEST" error code; however my
> attempts at catching it (or any error code) has been unfruitful.
>
> This is an obvious merge blocker, help wanted! Disabling TLS1.3 in the
> priority string works as a last-resort workaround.
>
> [0] https://nikmav.blogspot.com/2018/05/gnutls-and-tls-13.html
I’ve submitted a bunch of changes upstream to better support
post-handshake re-authentication:
https://gitlab.com/gnutls/gnutls/merge_requests/1026
In particular, this adds ‘connection-flag/post-handshake-auth’ and
‘connection-flag/auto-reauth’, which can be passed to ‘make-session’.
But as it turns out, there’s one patch that, alone, appears to fix the
issue above:
https://gitlab.com/civodul/gnutls/commit/7421ca2cfd2d9f4ac89bdec786eb745533430316
Ideally we’d wait for the next GnuTLS release that includes all of this.
However, if that helps, we can apply this patch to the ‘gnutls’ package
in ‘core-updates’ in the meantime.
WDYT?
Ludo’.
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commit 7421ca2cfd2d9f4ac89bdec786eb745533430316
Author: Ludovic Courtès <ludo@gnu.org>
Date: Wed Jun 12 11:32:19 2019 +0200
guile: Loop upon EAGAIN or EINTR.
* guile/src/core.c (do_fill_port) [USING_GUILE_BEFORE_2_2]: Loop while
'gnutls_record_recv' returns GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED.
(read_from_session_record_port) [!USING_GUILE_BEFORE_2_2]: Likewise.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
diff --git a/guile/src/core.c b/guile/src/core.c
index 546d63a1e3..8b9aa62560 100644
--- a/guile/src/core.c
+++ b/guile/src/core.c
@@ -1,5 +1,5 @@
/* GnuTLS --- Guile bindings for GnuTLS.
- Copyright (C) 2007-2014, 2016 Free Software Foundation, Inc.
+ Copyright (C) 2007-2014, 2016, 2019 Free Software Foundation, Inc.
GnuTLS is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
@@ -869,8 +869,12 @@ do_fill_port (void *data)
const fill_port_data_t *args = (fill_port_data_t *) data;
c_port = args->c_port;
- result = gnutls_record_recv (args->c_session,
- c_port->read_buf, c_port->read_buf_size);
+
+ do
+ result = gnutls_record_recv (args->c_session,
+ c_port->read_buf, c_port->read_buf_size);
+ while (result == GNUTLS_E_AGAIN || result == GNUTLS_E_INTERRUPTED);
+
if (EXPECT_TRUE (result > 0))
{
c_port->read_pos = c_port->read_buf;
@@ -1002,7 +1006,12 @@ read_from_session_record_port (SCM port, SCM dst, size_t start, size_t count)
/* XXX: Leave guile mode when SCM_GNUTLS_SESSION_TRANSPORT_IS_FD is
true? */
- result = gnutls_record_recv (c_session, read_buf, count);
+ /* We can get EAGAIN for example if we received a reauth request, even when
+ GNUTLS_AUTO_REAUTH is set. In that case, loop again. */
+ do
+ result = gnutls_record_recv (c_session, read_buf, count);
+ while (result == GNUTLS_E_AGAIN || result == GNUTLS_E_INTERRUPTED);
+
if (EXPECT_FALSE (result < 0))
/* FIXME: Silently swallowed! */
scm_gnutls_error (result, FUNC_NAME);
^ permalink raw reply related [flat|nested] 6+ messages in thread