qemu-kvm/0018-curl-Make-sslverify-off-disable-host-as-well-as-peer.patch

From 49d4861ffc56cb233dacc1abcb2a5ec608e599ab Mon Sep 17 00:00:00 2001
From: Jeffrey Cody <jcody@redhat.com>
Date: Wed, 26 Sep 2018 04:08:14 +0100
Subject: curl: Make sslverify=off disable host as well as peer verification.

RH-Author: Jeffrey Cody <jcody@redhat.com>
Message-id: <543d2f667af465dd809329fcba5175bc974d58d4.1537933576.git.jcody@redhat.com>
Patchwork-id: 82293
O-Subject: [RHEL8/rhel qemu-kvm PATCH 1/1] curl: Make sslverify=off disable host as well as peer verification.
Bugzilla: 1575925
RH-Acked-by: Richard Jones <rjones@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>

From: "Richard W.M. Jones" <rjones@redhat.com>

The sslverify setting is supposed to turn off all TLS certificate
checks in libcurl.  However because of the way we use it, it only
turns off peer certificate authenticity checks
(CURLOPT_SSL_VERIFYPEER).  This patch makes it also turn off the check
that the server name in the certificate is the same as the server
you're connecting to (CURLOPT_SSL_VERIFYHOST).

We can use Google's server at 8.8.8.8 which happens to have a bad TLS
certificate to demonstrate this:

$ ./qemu-img create -q -f qcow2 -b 'json: { "file.sslverify": "off", "file.driver": "https", "file.url": "https://8.8.8.8/foo" }' /var/tmp/file.qcow2
qemu-img: /var/tmp/file.qcow2: CURL: Error opening file: SSL: no alternative certificate subject name matches target host name '8.8.8.8'
Could not open backing image to determine size.

With this patch applied, qemu-img connects to the server regardless of
the bad certificate:

$ ./qemu-img create -q -f qcow2 -b 'json: { "file.sslverify": "off", "file.driver": "https", "file.url": "https://8.8.8.8/foo" }' /var/tmp/file.qcow2
qemu-img: /var/tmp/file.qcow2: CURL: Error opening file: The requested URL returned error: 404 Not Found

(The 404 error is expected because 8.8.8.8 is not actually serving a
file called "/foo".)

Of course the default (without sslverify=off) remains to always check
the certificate:

$ ./qemu-img create -q -f qcow2 -b 'json: { "file.driver": "https", "file.url": "https://8.8.8.8/foo" }' /var/tmp/file.qcow2
qemu-img: /var/tmp/file.qcow2: CURL: Error opening file: SSL: no alternative certificate subject name matches target host name '8.8.8.8'
Could not open backing image to determine size.

Further information about the two settings is available here:

https://curl.haxx.se/libcurl/c/CURLOPT_SSL_VERIFYPEER.html
https://curl.haxx.se/libcurl/c/CURLOPT_SSL_VERIFYHOST.html

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 20180914095622.19698-1-rjones@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
(cherry picked from commit 637fa44ab80c6b317adf1d117494325a95daad60)
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 block/curl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/curl.c b/block/curl.c
index 229bb84..fabb2b4 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -483,6 +483,8 @@ static int curl_init_state(BDRVCURLState *s, CURLState *state)
         curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
         curl_easy_setopt(state->curl, CURLOPT_SSL_VERIFYPEER,
                          (long) s->sslverify);
+        curl_easy_setopt(state->curl, CURLOPT_SSL_VERIFYHOST,
+                         s->sslverify ? 2L : 0L);
         if (s->cookie) {
             curl_easy_setopt(state->curl, CURLOPT_COOKIE, s->cookie);
         }
-- 
1.8.3.1