nss: Fall back to latest supported SSL version #3337

pghmcfc · 2018-12-03T11:53:12Z

NSS may be built without support for the latest SSL/TLS versions, leading to "SSL version range is not valid" errors when the library code supports a recent version (e.g. TLS v1.3) but it has explicitly been disabled.

This change adjusts the maximum SSL version requested by libcurl to be the maximum supported version at runtime, as long as that version is at least as high as the minimum version required by libcurl.

Fixes #3261

Note: The SSL_VersionRangeGetSupported API was added in NSS version 3.14 (https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.14_release_notes), same as the SSL_VersionRangeGetDefault API, which is already used in curl, so there should be no change in NSS version requirements.

bagder · 2018-12-03T23:07:07Z

travis reports a little nit:

./vtls/nss.c:1839:5: warning: if with space (SPACEBEFOREPAREN)
   if (sslver_supported.max < sslver.max &&
     ^

NSS may be built without support for the latest SSL/TLS versions, leading to "SSL version range is not valid" errors when the library code supports a recent version (e.g. TLS v1.3) but it has explicitly been disabled. This change adjusts the maximum SSL version requested by libcurl to be the maximum supported version at runtime, as long as that version is at least as high as the minimum version required by libcurl. Fixes curl#3261

bagder

We could possibly consider outputting the numerical TLS version numbers as hex, as they are defined as hex in the NSS header file.

pghmcfc · 2018-12-04T09:13:46Z

I think it would be even better to output them as text strings like "TLSv1.2" where the values are known, and maybe hex otherwise. Perhaps have a function nss_sslver_to_string that's structured like nss_sslver_from_curl?

kdudka · 2018-12-04T12:05:13Z

@pghmcfc Sounds good!

pghmcfc · 2018-12-04T12:28:26Z

How's this look?

$ curl -v "https://github.com/curl/curl/issues/new" --tlsv1.2
*   Trying 192.30.253.112...
* TCP_NODELAY set
* Connected to github.com (192.30.253.112) port 443 (#0)
* Initializing NSS with certpath: sql:/etc/pki/nssdb
* Falling back from TLSv1.3 to max supported SSL version (TLSv1.2)
*   CAfile: none
  CApath: none
* loaded libnssckbi.so
* ALPN, server accepted to use http/1.1
* SSL connection using TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
* Server certificate:
* 	subject: CN=github.com,O="GitHub, Inc.",L=San Francisco,ST=California,C=US,serialNumber=5157550,incorporationState=Delaware,incorporationCountry=US,businessCategory=Private Organization
* 	start date: May 08 00:00:00 2018 GMT
* 	expire date: Jun 03 12:00:00 2020 GMT
* 	common name: github.com
* 	issuer: CN=DigiCert SHA2 Extended Validation Server CA,OU=www.digicert.com,O=DigiCert Inc,C=US
> GET /curl/curl/issues/new HTTP/1.1
> Host: github.com
> User-Agent: curl/7.62.0
> Accept: */*
> 
< HTTP/1.1 302 Found
< Server: GitHub.com
< Date: Tue, 04 Dec 2018 12:26:39 GMT
< Content-Type: text/html; charset=utf-8
< Transfer-Encoding: chunked
< Status: 302 Found
< Cache-Control: no-cache
< Vary: X-PJAX
< Location: https://github.com/login?return_to=https%3A%2F%2Ffanyv88.com%3A443%2Fhttps%2Fgithub.com%2Fcurl%2Fcurl%2Fissues%2Fnew
< Set-Cookie: has_recent_activity=1; path=/; expires=Tue, 04 Dec 2018 13:26:39 -0000
< Set-Cookie: _gh_sess=OTlnV3M2a1JLcTliT2VYWWRIVWdTc1hRcWdNaVpjMTNqYjZ4ZExYb2hHcmRWYUZHRzdiSGd3NmYrMnpQL3F6R2xJN0hSeklWWjQyZ1g2cmZlQVpPN1NzZFA2MkVVODY0QVc4L3poM1JOZ1l5WlRndktMR2RIRVZvWTVXMERxUS9lZC9yekxXSi9HNU9lUHdCQVRFSWdiaUtGV0t4R1FBVisvdk1ieUVjZDBMMVZraU9HS2FCbW1MbVlpdHhvcTlBLS1zUjZyd1ZmenJISUxWM21TaWg4K1RRPT0%3D--ade31fe886abc73903b35681535b3076b0fd36bf; path=/; secure; HttpOnly
< X-Request-Id: f9ecf2a6-3d94-4cd0-81d7-6377cfd9d426
< Strict-Transport-Security: max-age=31536000; includeSubdomains; preload
< X-Frame-Options: deny
< X-Content-Type-Options: nosniff
< X-XSS-Protection: 1; mode=block
< Expect-CT: max-age=2592000, report-uri="https://api.github.com/_private/browser/errors"
< Content-Security-Policy: default-src 'none'; base-uri 'self'; block-all-mixed-content; connect-src 'self' uploads.github.com status.github.com collector.githubapp.com api.github.com www.google-analytics.com github-cloud.s3.amazonaws.com github-production-repository-file-5c1aeb.s3.amazonaws.com github-production-upload-manifest-file-7fdce7.s3.amazonaws.com github-production-user-asset-6210df.s3.amazonaws.com wss://live.github.com; font-src assets-cdn.github.com; form-action 'self' github.com gist.github.com; frame-ancestors 'none'; frame-src render.githubusercontent.com; img-src 'self' data: assets-cdn.github.com identicons.github.com collector.githubapp.com github-cloud.s3.amazonaws.com *.githubusercontent.com; manifest-src 'self'; media-src 'none'; script-src assets-cdn.github.com; style-src 'unsafe-inline' assets-cdn.github.com
< X-GitHub-Request-Id: A564:5DE5:21CADF0:41C15E2:5C06727F
< 
* Connection #0 to host github.com left intact
<html><body>You are being <a href="https://github.com/login?return_to=https%3A%2F%2Ffanyv88.com%3A443%2Fhttps%2Fgithub.com%2Fcurl%2Fcurl%2Fissues%2Fnew">redirected</a>.</body></html>

kdudka

Besides the style issues, it looks fine to me.

lib/vtls/nss.c

Use descriptive text strings rather than decimal numbers.

kdudka · 2018-12-04T14:34:48Z

Thanks for the fix-ups!

While reviewing the #ifdefs I spotted that the code already uses SSL_LIBRARY_VERSION_TLS_1_2 without checking its availability first, which makes some of the #ifdefs redundant. But this could be cleaned up later.

pghmcfc · 2018-12-04T16:28:11Z

Maybe the other uses of SSL_LIBRARY_VERSION_TLS_1_2 should be protected. The configure script looks for the function SSL_VersionRangeSet to verify that NSS is usable, and that was introduced in NSS version 3.14 (https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.14_release_notes), which supported up to TLSv1.1. TLSv1.2 support (and hence the SSL_LIBRARY_VERSION_TLS_1_2 define) was added in NSS version 3.15.1 (https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.15.1_release_notes).

kdudka · 2018-12-04T17:40:42Z

Actually, it should be easy to make it consistent (and compatible with old NSS releases) again:

--- a/lib/vtls/nss.c
+++ b/lib/vtls/nss.c
@@ -1807,10 +1807,14 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex)
   SSLVersionRange sslver = {
     SSL_LIBRARY_VERSION_TLS_1_0,  /* min */
 #ifdef SSL_LIBRARY_VERSION_TLS_1_3
     SSL_LIBRARY_VERSION_TLS_1_3   /* max */
-#else
+#elif defined SSL_LIBRARY_VERSION_TLS_1_2
     SSL_LIBRARY_VERSION_TLS_1_2
+#elif defined SSL_LIBRARY_VERSION_TLS_1_1
+    SSL_LIBRARY_VERSION_TLS_1_1
+#else
+    SSL_LIBRARY_VERSION_TLS_1_0
 #endif
   };

   BACKEND->data = data;

pghmcfc · 2018-12-04T19:17:32Z

Yes, that's fixed the build on Fedoras 16 and 17.

kdudka · 2018-12-05T12:28:40Z

Perfect. Thank you for working on this!

bagder · 2018-12-05T13:18:56Z

I'm puzzed by the DoH torture test failures on travis (test 2100) which indeed is not happening due to this change.

bagder · 2018-12-05T14:23:56Z

(doh leak now worked on in #3342)

bagder · 2018-12-05T14:25:16Z

Thanks a lot both of you!

bagder · 2018-12-05T14:28:07Z

Landed in 6848ea5

pghmcfc mentioned this pull request Dec 3, 2018

Error 35 when running curl with --tlsv1.2 option (Curl version 7.62.0) #3261

Closed

pghmcfc force-pushed the nss-ssl-version-fallback branch from 109abb8 to 0751db5 Compare December 4, 2018 06:51

bagder mentioned this pull request Dec 4, 2018

nss: if built with disabled TLS 1.3, do an extra TLS version range check #3334

Closed

bagder added the TLS label Dec 4, 2018

bagder approved these changes Dec 4, 2018

View reviewed changes

kdudka approved these changes Dec 4, 2018

View reviewed changes

lib/vtls/nss.c Outdated Show resolved Hide resolved

lib/vtls/nss.c Outdated Show resolved Hide resolved

nss: Improve info message when falling back SSL protocol

01d4b54

Use descriptive text strings rather than decimal numbers.

pghmcfc force-pushed the nss-ssl-version-fallback branch from a4ed6fe to 01d4b54 Compare December 4, 2018 14:15

nss: Fix compatibility with nss versions 3.14 to 3.15

98e9843

pghmcfc force-pushed the nss-ssl-version-fallback branch from 54a6372 to 98e9843 Compare December 4, 2018 19:18

bagder closed this Dec 5, 2018

lock bot locked as resolved and limited conversation to collaborators Mar 5, 2019

pghmcfc deleted the nss-ssl-version-fallback branch March 11, 2020 13:09

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

nss: Fall back to latest supported SSL version #3337

nss: Fall back to latest supported SSL version #3337

pghmcfc commented Dec 3, 2018

bagder commented Dec 3, 2018

bagder left a comment

pghmcfc commented Dec 4, 2018

kdudka commented Dec 4, 2018

pghmcfc commented Dec 4, 2018

kdudka left a comment

kdudka commented Dec 4, 2018

pghmcfc commented Dec 4, 2018

kdudka commented Dec 4, 2018

pghmcfc commented Dec 4, 2018

kdudka commented Dec 5, 2018

bagder commented Dec 5, 2018

bagder commented Dec 5, 2018

bagder commented Dec 5, 2018

bagder commented Dec 5, 2018

nss: Fall back to latest supported SSL version #3337

nss: Fall back to latest supported SSL version #3337

Conversation

pghmcfc commented Dec 3, 2018

bagder commented Dec 3, 2018

bagder left a comment

Choose a reason for hiding this comment

pghmcfc commented Dec 4, 2018

kdudka commented Dec 4, 2018

pghmcfc commented Dec 4, 2018

kdudka left a comment

Choose a reason for hiding this comment

kdudka commented Dec 4, 2018

pghmcfc commented Dec 4, 2018

kdudka commented Dec 4, 2018

pghmcfc commented Dec 4, 2018

kdudka commented Dec 5, 2018

bagder commented Dec 5, 2018

bagder commented Dec 5, 2018

bagder commented Dec 5, 2018

bagder commented Dec 5, 2018