Subject: Re: bug#46342: 28.0.50; socks-send-command munges IP address bytes to UTF-8

From: "J.P." <[email-masked]>
Date: Wed, 17 Feb 2021 06:59:07 -0800

Eli Zaretskii <[email-masked]> writes:

> So what is the problem with using unibyte-string for producing a
> unibyte string from a list of bytes?  It sounds like it's exactly
> what is needed here, and is actually used in some places in socks.el.

Great, thanks. That's what was needed indeed. I've updated things
accordingly and have added a doc string to socks-send-command explaining
the address parameter.

>From 4e058c6a78f8a219d159444aadaf5e9cf5004870 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <[email-masked]>
Date: Fri, 5 Feb 2021 05:24:55 -0800
Subject: [PATCH 1/2] Add more auth-related tests for socks.el

* test/lisp/net/socks-tests.el (auth-registration-and-suite-offer)
(filter-response-parsing-v4, filter-response-parsing-v5): Assert
auth-method selection wrangling and socks-filter parsing.
(v5-auth-user-pass, v5-auth-user-pass-blank, v5-auth-none): Show prep
and execution of the SOCKS connect command and proxying of an HTTP
request; simplify fake server.
---
 test/lisp/net/socks-tests.el | 270 ++++++++++++++++++++++++++++-------
 1 file changed, 215 insertions(+), 55 deletions(-)

diff --git a/test/lisp/net/socks-tests.el b/test/lisp/net/socks-tests.el
index b378ed2964e..340a42d79cc 100644
--- a/test/lisp/net/socks-tests.el
+++ b/test/lisp/net/socks-tests.el
@@ -21,68 +21,151 @@
 
 ;;; Code:
 
+(require 'ert)
 (require 'socks)
 (require 'url-http)
 
-(defvar socks-tests-canned-server-port nil)
+(ert-deftest socks-tests-auth-registration-and-suite-offer ()
+  (ert-info ("Default favors user/pass auth")
+    (should (equal socks-authentication-methods
+                   '((2 "Username/Password" . socks-username/password-auth)
+                     (0 "No authentication" . identity))))
+    (should (equal "\2\0\2" (socks-build-auth-list)))) ; length [offer ...]
+  (let (socks-authentication-methods)
+    (ert-info ("Empty selection/no methods offered")
+      (should (equal "\0" (socks-build-auth-list))))
+    (ert-info ("Simulate library defaults")
+      (socks-register-authentication-method 0 "No authentication"
+                                            'identity)
+      (should (equal socks-authentication-methods
+                     '((0 "No authentication" . identity))))
+      (should (equal "\1\0" (socks-build-auth-list)))
+      (socks-register-authentication-method 2 "Username/Password"
+                                            'socks-username/password-auth)
+      (should (equal socks-authentication-methods
+                     '((2 "Username/Password" . socks-username/password-auth)
+                       (0 "No authentication" . identity))))
+      (should (equal "\2\0\2" (socks-build-auth-list))))
+    (ert-info ("Removal")
+      (socks-unregister-authentication-method 2)
+      (should (equal socks-authentication-methods
+                     '((0 "No authentication" . identity))))
+      (should (equal "\1\0" (socks-build-auth-list)))
+      (socks-unregister-authentication-method 0)
+      (should-not socks-authentication-methods)
+      (should (equal "\0" (socks-build-auth-list))))))
 
-(defun socks-tests-canned-server-create (verbatim patterns)
-  "Create a fake SOCKS server and return the process.
+(ert-deftest socks-tests-filter-response-parsing-v4 ()
+  "Ensure new chunks added on right (Bug#45162)."
+  (let* ((buf (generate-new-buffer "*test-socks-filter*"))
+         (proc (start-process "test-socks-filter" buf "sleep" "1")))
+    (process-put proc 'socks t)
+    (process-put proc 'socks-state socks-state-waiting)
+    (process-put proc 'socks-server-protocol 4)
+    (ert-info ("Receive initial incomplete segment")
+      (socks-filter proc (concat [0 90 0 0 93 184 216]))
+      ;; From example.com: OK status ^      ^ msg start
+      (ert-info ("State still set to waiting")
+        (should (eq (process-get proc 'socks-state) socks-state-waiting)))
+      (ert-info ("Response field is nil because processing incomplete")
+        (should-not (process-get proc 'socks-response)))
+      (ert-info ("Scratch field holds stashed partial payload")
+        (should (string= (concat [0 90 0 0 93 184 216])
+                         (process-get proc 'socks-scratch)))))
+    (ert-info ("Last part arrives")
+      (socks-filter proc "\42") ; ?\" 34
+      (ert-info ("State transitions to complete (length check passes)")
+        (should (eq (process-get proc 'socks-state) socks-state-connected)))
+      (ert-info ("Scratch and response fields hold stash w. last chunk")
+        (should (string= (concat [0 90 0 0 93 184 216 34])
+                         (process-get proc 'socks-response)))
+        (should (string= (process-get proc 'socks-response)
+                         (process-get proc 'socks-scratch)))))
+    (delete-process proc)
+    (kill-buffer buf)))
 
-`VERBATIM' and `PATTERNS' are dotted alists containing responses.
-Requests are tried in order.  On failure, an error is raised."
-  (let* ((buf (generate-new-buffer "*canned-socks-server*"))
+(ert-deftest socks-tests-filter-response-parsing-v5 ()
+  "Ensure new chunks added on right (Bug#45162)."
+  (let* ((buf (generate-new-buffer "*test-socks-filter*"))
+         (proc (start-process "test-socks-filter" buf "sleep" "1")))
+    (process-put proc 'socks t)
+    (process-put proc 'socks-state socks-state-waiting)
+    (process-put proc 'socks-server-protocol 5)
+    (ert-info ("Receive initial incomplete segment")
+      ;; From fedora.org: 2605:bc80:3010:600:dead:beef:cafe:fed9
+      ;; 5004 ~~> Version Status (OK) NOOP Addr-Type (4 -> IPv6)
+      (socks-filter proc "\5\0\0\4\x26\x05\xbc\x80\x30\x10\x00\x60")
+      (ert-info ("State still waiting and response emtpy")
+        (should (eq (process-get proc 'socks-state) socks-state-waiting))
+        (should-not (process-get proc 'socks-response)))
+      (ert-info ("Scratch field holds partial payload of pending msg")
+        (should (string= "\5\0\0\4\x26\x05\xbc\x80\x30\x10\x00\x60"
+                         (process-get proc 'socks-scratch)))))
+    (ert-info ("Middle chunk arrives")
+      (socks-filter proc "\xde\xad\xbe\xef\xca\xfe\xfe\xd9")
+      (ert-info ("State and response fields still untouched")
+        (should (eq (process-get proc 'socks-state) socks-state-waiting))
+        (should-not (process-get proc 'socks-response)))
+      (ert-info ("Scratch contains new arrival appended (on RHS)")
+        (should (string=  (concat "\5\0\0\4"
+                                  "\x26\x05\xbc\x80\x30\x10\x00\x60"
+                                  "\xde\xad\xbe\xef\xca\xfe\xfe\xd9")
+                          (process-get proc 'socks-scratch)))))
+    (ert-info ("Final part arrives (port number)")
+      (socks-filter proc "\0\0")
+      (ert-info ("State transitions to complete")
+        (should (eq (process-get proc 'socks-state) socks-state-connected)))
+      (ert-info ("Scratch and response fields show last chunk appended")
+        (should (string=  (concat "\5\0\0\4"
+                                  "\x26\x05\xbc\x80\x30\x10\x00\x60"
+                                  "\xde\xad\xbe\xef\xca\xfe\xfe\xd9"
+                                  "\0\0")
+                          (process-get proc 'socks-scratch)))
+        (should (string= (process-get proc 'socks-response)
+                         (process-get proc 'socks-scratch)))))
+    (delete-process proc)
+    (kill-buffer buf)))
+
+(defvar socks-tests-canned-server-patterns nil
+  "Alist containing request/response cons pairs to be tried in order.
+Vectors must match verbatim. Strings are considered regex patterns.")
+
+(defun socks-tests-canned-server-create ()
+  "Create and return a fake SOCKS server."
+  (let* ((port (nth 2 socks-server))
+         (name (format "socks-server:%d" port))
+         (pats socks-tests-canned-server-patterns)
          (filt (lambda (proc line)
-                 (let ((resp (or (assoc-default line verbatim
-                                                (lambda (k s) ; s is line
-                                                  (string= (concat k) s)))
-                                 (assoc-default line patterns
-                                                (lambda (p s)
-                                                  (string-match-p p s))))))
-                   (unless resp
+                 (pcase-let ((`(,pat . ,resp) (pop pats)))
+                   (unless (or (and (vectorp pat) (equal pat (vconcat line)))
+                               (string-match-p pat line))
                      (error "Unknown request: %s" line))
                    (let ((print-escape-control-characters t))
-                     (princ (format "<- %s\n" (prin1-to-string line)) buf)
-                     (princ (format "-> %s\n" (prin1-to-string resp)) buf))
+                     (message "[%s] <- %s" name (prin1-to-string line))
+                     (message "[%s] -> %s" name (prin1-to-string resp)))
                    (process-send-string proc (concat resp)))))
-         (srv (make-network-process :server 1
-                                    :buffer buf
-                                    :filter filt
-                                    :name "server"
-                                    :family 'ipv4
-                                    :host 'local
-                                    :service socks-tests-canned-server-port)))
-    (set-process-query-on-exit-flag srv nil)
-    (princ (format "[%s] Listening on localhost:10080\n" srv) buf)
-    srv))
-
-;; Add ([5 3 0 1 2] . [5 2]) to the `verbatim' list below to validate
-;; against curl 7.71 with the following options:
-;; $ curl --verbose -U foo:bar --proxy socks5h://127.0.0.1:10080 example.com
-;;
-;; If later implementing version 4a, try these:
-;; [4 1 0 80 0 0 0 1 0 ?e ?x ?a ?m ?p ?l ?e ?. ?c ?o ?m 0] . [0 90 0 0 0 0 0 0]
-;; $ curl --verbose --proxy socks4a://127.0.0.1:10080 example.com
+         (serv (make-network-process :server 1
+                                     :buffer (get-buffer-create name)
+                                     :filter filt
+                                     :name name
+                                     :family 'ipv4
+                                     :host 'local
+                                     :coding 'binary
+                                     :service port)))
+    (set-process-query-on-exit-flag serv nil)
+    serv))
 
-(ert-deftest socks-tests-auth-filter-url-http ()
-  "Verify correct handling of SOCKS5 user/pass authentication."
-  (let* ((socks-server '("server" "127.0.0.1" 10080 5))
-         (socks-username "foo")
-         (socks-password "bar")
-         (url-gateway-method 'socks)
+(defvar socks-tests--hello-world-http-request-pattern
+  (cons "^GET /" (concat "HTTP/1.1 200 OK\r\n"
+                         "Content-Type: text/plain\r\n"
+                         "Content-Length: 13\r\n\r\n"
+                         "Hello World!\n")))
+
+(defun socks-tests-perform-hello-world-http-request ()
+  "Start canned server, validate hello-world response, and finalize."
+  (let* ((url-gateway-method 'socks)
          (url (url-generic-parse-url "http://example.com"))
-         (verbatim '(([5 2 0 2] . [5 2])
-                     ([1 3 ?f ?o ?o 3 ?b ?a ?r] . [1 0])
-                     ([5 1 0 3 11 ?e ?x ?a ?m ?p ?l ?e ?. ?c ?o ?m 0 80]
-                      . [5 0 0 1 0 0 0 0 0 0])))
-         (patterns
-          `(("^GET /" . ,(concat "HTTP/1.1 200 OK\r\n"
-                                 "Content-Type: text/plain; charset=UTF-8\r\n"
-                                 "Content-Length: 13\r\n\r\n"
-                                 "Hello World!\n"))))
-         (socks-tests-canned-server-port 10080)
-         (server (socks-tests-canned-server-create verbatim patterns))
-         (tries 10)
+         (server (socks-tests-canned-server-create))
          ;;
          done
          ;;
@@ -90,14 +173,91 @@ socks-tests-auth-filter-url-http
                (goto-char (point-min))
                (should (search-forward "Hello World" nil t))
                (setq done t)))
-         (buf (url-http url cb '(nil))))
-    (ert-info ("Connect to HTTP endpoint over SOCKS5 with USER/PASS method")
-      (while (and (not done) (< 0 (cl-decf tries))) ; cl-lib via url-http
-        (sleep-for 0.1)))
+         (buf (url-http url cb '(nil)))
+         (proc (get-buffer-process buf))
+         (attempts 10))
+    (while (and (not done) (< 0 (cl-decf attempts)))
+      (sleep-for 0.1))
     (should done)
     (delete-process server)
+    (delete-process proc) ; otherwise seems client proc is sometimes reused
     (kill-buffer (process-buffer server))
     (kill-buffer buf)
     (ignore url-gateway-method)))
 
+;; Replace first pattern below with ([5 3 0 1 2] . [5 2]) to validate
+;; against curl 7.71 with the following options:
+;; $ curl --verbose -U foo:bar --proxy socks5h://127.0.0.1:10080 example.com
+
+(ert-deftest socks-tests-v5-auth-user-pass ()
+  "Verify correct handling of SOCKS5 user/pass authentication."
+  (should (assq 2 socks-authentication-methods))
+  (let ((socks-server '("server" "127.0.0.1" 10080 5))
+        (socks-username "foo")
+        (socks-password "bar")
+        (url-user-agent "Test/auth-user-pass")
+        (socks-tests-canned-server-patterns
+         `(([5 2 0 2] . [5 2])
+           ([1 3 ?f ?o ?o 3 ?b ?a ?r] . [1 0])
+           ([5 1 0 3 11 ?e ?x ?a ?m ?p ?l ?e ?. ?c ?o ?m 0 80]
+            . [5 0 0 1 0 0 0 0 0 0])
+           ,socks-tests--hello-world-http-request-pattern)))
+    (ert-info ("Make HTTP request over SOCKS5 with USER/PASS auth method")
+      (socks-tests-perform-hello-world-http-request))))
+
+;; Services (like Tor) may be configured without auth but for some
+;; reason still prefer the user/pass method over none when offered both.
+;; Given this library's defaults, the scenario below is possible.
+;;
+;; FYI: RFC 1929 doesn't say that a username or password is required
+;; but notes that the length of both fields should be at least one.
+;; However, both socks.el and curl send zero-length fields (though
+;; curl drops the user part too when the password is empty).
+;;
+;; From Tor's docs /socks-extensions.txt, 1.1 Extent of support:
+;; > We allow username/password fields of this message to be empty ...
+;; line 41 in blob 5fd1f828f3e9d014f7b65fa3bd1d33c39e4129e2
+;; https://gitweb.torproject.org/torspec.git/tree/socks-extensions.txt
+;;
+;; To verify against curl 7.71, swap out the first two pattern pairs
+;; with ([5 3 0 1 2] . [5 2]) and ([1 0 0] . [1 0]), then run:
+;; $ curl verbose -U "foo:" --proxy socks5h://127.0.0.1:10081 example.com
+
+(ert-deftest socks-tests-v5-auth-user-pass-blank ()
+  "Verify correct SOCKS5 user/pass authentication with empty pass."
+  (should (assq 2 socks-authentication-methods))
+  (let ((socks-server '("server" "127.0.0.1" 10081 5))
+        (socks-username "foo") ; defaults to (user-login-name)
+        (socks-password "") ; simulate user hitting enter when prompted
+        (url-user-agent "Test/auth-user-pass-blank")
+        (socks-tests-canned-server-patterns
+         `(([5 2 0 2] . [5 2])
+           ([1 3 ?f ?o ?o 0] . [1 0])
+           ([5 1 0 3 11 ?e ?x ?a ?m ?p ?l ?e ?. ?c ?o ?m 0 80]
+            . [5 0 0 1 0 0 0 0 0 0])
+           ,socks-tests--hello-world-http-request-pattern)))
+    (ert-info ("Make HTTP request over SOCKS5 with USER/PASS auth method")
+      (socks-tests-perform-hello-world-http-request))))
+
+;; Swap out ([5 2 0 1] . [5 0]) with the first pattern below to validate
+;; against curl 7.71 with the following options:
+;; $ curl --verbose --proxy socks5h://127.0.0.1:10082 example.com
+
+(ert-deftest socks-tests-v5-auth-none ()
+  "Verify correct handling of SOCKS5 when auth method 0 requested."
+  (let ((socks-server '("server" "127.0.0.1" 10082 5))
+        (socks-authentication-methods (append socks-authentication-methods
+                                              nil))
+        (url-user-agent "Test/auth-none")
+        (socks-tests-canned-server-patterns
+         `(([5 1 0] . [5 0])
+           ([5 1 0 3 11 ?e ?x ?a ?m ?p ?l ?e ?. ?c ?o ?m 0 80]
+            . [5 0 0 1 0 0 0 0 0 0])
+           ,socks-tests--hello-world-http-request-pattern)))
+    (socks-unregister-authentication-method 2)
+    (should-not (assq 2 socks-authentication-methods))
+    (ert-info ("Make HTTP request over SOCKS5 with no auth method")
+      (socks-tests-perform-hello-world-http-request)))
+  (should (assq 2 socks-authentication-methods)))
+
 ;;; socks-tests.el ends here
-- 
2.29.2

>From 7daa1e7f1c8581e3aaab8cf94731de8e1d140fae Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <[email-masked]>
Date: Fri, 5 Feb 2021 19:41:04 -0800
Subject: [PATCH 2/2] Use raw bytes for SOCKS 4 IP addresses

* lisp/net/socks.el: (socks--open-network-stream, socks-send-command):
* test/lisp/net/socks-tests.el: (socks-tests-v4-basic): (Bug#46342).
---
 lisp/net/socks.el            |  4 +++-
 test/lisp/net/socks-tests.el | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/lisp/net/socks.el b/lisp/net/socks.el
index 96fafc826b8..1da1d31d678 100644
--- a/lisp/net/socks.el
+++ b/lisp/net/socks.el
@@ -390,6 +390,8 @@ socks-open-connection
       proc)))
 
 (defun socks-send-command (proc command atype address port)
+  "Send COMMAND to SOCKS service PROC for proxying ADDRESS and PORT.
+When ATYPE indicates an IP, param ADDRESS must be given as raw bytes."
   (let ((addr (cond
 	       ((or (= atype socks-address-type-v4)
 		    (= atype socks-address-type-v6))
@@ -528,7 +530,7 @@ socks--open-network-stream
 	        (setq host (socks-nslookup-host host))
 	        (if (not (listp host))
 	            (error "Could not get IP address for: %s" host))
-	        (setq host (apply #'format "%c%c%c%c" host))
+		(setq host (apply #'unibyte-string host))
                 socks-address-type-v4)
                (t
                 socks-address-type-name))))
diff --git a/test/lisp/net/socks-tests.el b/test/lisp/net/socks-tests.el
index 340a42d79cc..9a2dcba9daf 100644
--- a/test/lisp/net/socks-tests.el
+++ b/test/lisp/net/socks-tests.el
@@ -185,6 +185,26 @@ socks-tests-perform-hello-world-http-request
     (kill-buffer buf)
     (ignore url-gateway-method)))
 
+;; Unlike curl, socks.el includes the ID field (but otherwise matches):
+;; $ curl --proxy socks4://127.0.0.1:1080 example.com
+
+(ert-deftest socks-tests-v4-basic ()
+  "Show correct preparation of SOCKS4 connect command (Bug#46342)."
+  (let ((socks-server '("server" "127.0.0.1" 10079 4))
+        (url-user-agent "Test/4-basic")
+        (socks-tests-canned-server-patterns
+         `(([4 1 0 80 93 184 216 34 ?f ?o ?o 0] . [0 90 0 0 0 0 0 0])
+           ,socks-tests--hello-world-http-request-pattern))
+        socks-nslookup-program)
+    (ert-info ("Make HTTP request over SOCKS4")
+      (cl-letf (((symbol-function 'socks-nslookup-host)
+                 (lambda (host)
+                   (should (equal host "example.com"))
+                   (list 93 184 216 34)))
+                ((symbol-function 'user-full-name)
+                 (lambda () "foo")))
+        (socks-tests-perform-hello-world-http-request)))))
+
 ;; Replace first pattern below with ([5 3 0 1 2] . [5 2]) to validate
 ;; against curl 7.71 with the following options:
 ;; $ curl --verbose -U foo:bar --proxy socks5h://127.0.0.1:10080 example.com
-- 
2.29.2