commit 87abfd89e39e1d4c5d245e0e9f1e62989288701a Author: rl1987 <rl1987@sdf.lonestar.org> Date: Tue Feb 12 19:12:03 2019 +0200 Document more differences between SOCKS5 RFCs and how Tor implements SOCKS5 --- socks-extensions.txt | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/socks-extensions.txt b/socks-extensions.txt index ab37670..ed249ad 100644 --- a/socks-extensions.txt +++ b/socks-extensions.txt @@ -9,7 +9,7 @@ Tor's extensions to the SOCKS protocol been established, the client application uses the TCP stream as usual. Tor supports SOCKS4 as defined in [1], SOCKS4A as defined in [2], and - SOCKS5 as defined in [3]. + SOCKS5 as defined in [3] and [4]. The stickiest issue for Tor in supporting clients, in practice, is forcing DNS lookups to occur at the OR side: if clients do their own DNS lookup, @@ -30,13 +30,18 @@ Tor's extensions to the SOCKS protocol SOCKS5: - The (SOCKS5) "UDP ASSOCIATE" command is not supported. + - SOCKS5 BIND command is not supported. - IPv6 is not supported in CONNECT commands. + - SOCKS5 GSSAPI subnegotiation is not supported. - The "NO AUTHENTICATION REQUIRED" (SOCKS5) authentication method [00] is supported; and as of Tor 0.2.3.2-alpha, the "USERNAME/PASSWORD" (SOCKS5) authentication method [02] is supported too, and used as a method to implement stream isolation. As an extension to support some broken clients, - we allow clients to pass "USERNAME/PASSWORD" authentication to us even if - no authentication was selected. + we allow clients to pass "USERNAME/PASSWORD" authentication message to us + even if no authentication was selected. Furthermore, we allow + username/password fields of this message to be empty. This technically + violates RFC1929 [4], but ensures interoperability with somewhat broken + SOCKS5 client implementations. (For more information on stream isolation, see IsolateSOCKSAuth on the Tor manpage.) @@ -94,5 +99,6 @@ Tor's extensions to the SOCKS protocol References: [1] http://en.wikipedia.org/wiki/SOCKS#SOCKS4 [2] http://en.wikipedia.org/wiki/SOCKS#SOCKS4a - [3] SOCKS5: RFC1928 + [3] SOCKS5: RFC 1928 https://www.ietf.org/rfc/rfc1928.txt + [4] RFC 1929: https://www.ietf.org/rfc/rfc1929.txt