apt/methods, branch 1.3_rc2

methods: read config in most to least specific order

2016-08-17T19:53:05Z

The implementation of the generic config fallback did the fallback in the wrong order so that the least specific option wasn't the last value picked but in fact the first one… doh! So in the bugreports case http -> https -> http:: -> https:: while it should have been the reverse as before. Regression-In: 30060442025824c491f58887ca7369f3c572fa57 Closes: 834642

don't try pipelining if server closes connections

2016-08-16T17:20:28Z

If a server closes a connection after sending us a file that tends to mean that its a type of server who always closes the connection – it is therefore relatively pointless to try pipelining with it even if it isn't a problem by itself: apt is just restarting the pipeline each time after it got served one file and the connection is closed. The problem starts if one or more proxies are between the server and apt and they disagree about how the connection should be as in the bugreporters case where the responses apt gets contain both Keep-Alive and Proxy-Connection headers (which apt both ignores) indicating a proxy is trying to keep a connection open while the response also contains "Connection: close" indicating the opposite which apt understands and respects as it is required to do. We avoid stepping into this abyss by not performing pipelining anymore if we got a respond with the indication to close connection if the response was otherwise a success – error messages are sent by some servers via this method as their pages tend to be created dynamically and hence their size isn't known a priori to them. Closes: #832113

don't sent Range requests if we know its not accepted

2016-08-16T16:49:37Z

If the server told us in a previous request that it isn't supporting Ranges with bytes via an Accept-Ranges header missing bytes, we don't try to formulate requests using Ranges.

reorganize server-states resetting in http/https

2016-08-16T16:49:37Z

We keep various information bits about the server around, some only effecting the currently handled file (like sizes) while others should be persistent (like pipeline detections). http used to reset all file-related manually, which is a bit silly if we already have a Reset() method – which does reset all through –, so extending it with a parameter for reuse and calling it from https too (as this was previously resetting by just creating a new state struct – it uses no value of the persistent state-keeping yet as it supports no pipelining). Gbp-Dch: Ignore

http(s): allow empty values for header fields

2016-08-13T06:49:35Z

It seems completely pointless from a server-POV to sent empty header fields, so most of them don't do it (simply proven by this limitation existing since day one) – but it is technically allowed by the RFC as the surounding whitespaces are optional and Github seems to like sending "X-Geo-Block-List:\r\n" since recently (bug reports in other http clients indicate July) at least sometimes as the reporter claims to have seen it on https only even through it can happen with both. Closes: 834048

http: auto-configure for local Tor proxy if called as 'tor'

2016-08-10T23:34:39Z

With apts http transport supporting socks5h proxies and all the work in terms of configuration of methods based on the name it is called with it becomes surprisingly easy to implement Tor support equally (and perhaps even a bit exceeding) what is available currently in apt-transport-tor. How this will turn out to be handled packaging wise we will see in https://lists.debian.org/deity/2016/08/msg00012.html , but until this is resolved we can add the needed support without actively enabling it for now, so that this can be tested better.

block direct connections to .onion domains (RFC7687)

2016-08-10T23:34:39Z

Doing a direct connect to an .onion address (if you don't happen to use it as a local domain, which you shouldn't) is bound to fail and does leak the information that you do use Tor and which hidden service you wanted to connect to to a DNS server. Worse, if the DNS is poisoned and actually resolves tricking a user into believing the setup would work correctly… This does block also the usage of wrappers like torsocks with apt, but with native support available and advertised in the error message this shouldn't really be an issue. Inspired-by: https://bugzilla.mozilla.org/show_bug.cgi?id=1228457

implement socks5h proxy support for http method

2016-08-10T21:19:44Z

Socks support is a requested feature in sofar that the internet is actually believing Acquire::socks::Proxy would exist. It doesn't and this commit isn't adding it as that isn't how our configuration works, but it allows Acquire::http::Proxy="socks5h://…". The HTTPS method was changed already to support socks proxies (all versions) via curl. This commit implements only SOCKS5 (RFC1928) with no auth or pass&user auth (RFC1929), but not GSSAPI which is required by the RFC. The 'h' in the protocol name further indicates that DNS resolution is delegated to the socks proxy rather than performed locally. The implementation works and was tested with Tor as socks proxy for which implementing socks5h only can actually be considered a feature. Closes: 744934

implement generic config fallback for methods

2016-08-10T21:19:44Z

The https method implemented for a long while now a hardcoded fallback to the same options in http, which, while it works, is rather inflexible if we want to allow the methods to use another name to change their behavior slightly, like apt-transport-tor does to https – most of the diff being s#https#tor#g which then fails to do the full circle fallthrough tor -> https -> http for https sources. With this config infrastructure this could be implemented now.

use the same redirection handling for http and https

2016-08-10T21:19:44Z

cURL which backs our https implementation can handle redirects on its own, but by dealing with them on our own we gain finer control over which redirections will be performed (we don't like https → http) and by whom so that redirections to other hosts correctly spawn a new https method dealing with these instead of letting the current one deal with it.