From 637fa44ab80c6b317adf1d117494325a95daad60 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Fri, 14 Sep 2018 10:56:22 +0100 Subject: [PATCH] curl: Make sslverify=off disable host as well as peer verification. 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 Message-id: 20180914095622.19698-1-rjones@redhat.com Signed-off-by: Jeff Cody --- block/curl.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/curl.c b/block/curl.c index 229bb84a27..fabb2b4da7 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); } -- GitLab