substitute-binary: Support the Signature field of a narinfo file.

* guix/scripts/substitute-binary.scm (<narinfo>): Add the 'signature'
  and 'contents' fields.
  (narinfo-signature->canonical-sexp): New function.
  (narinfo-maker): Add the 'signature' argument and use it.
  (assert-valid-signature): New function.
  (read-narinfo): Support the Signature field.
  (write-narinfo): Use 'narinfo-contents'.
  (%allow-unauthenticated-substitutes?): New variable.
* guix/base64.scm, tests/base64.scm, tests/substitute-binary.scm: New files.
* Makefile.am (SCM_TESTS): Add tests/base64.scm and
  tests/substitute-binary.scm.
  (MODULES): Add guix/base64.scm.
* test-env.in: Set 'GUIX_ALLOW_UNAUTHENTICATED_SUBSTITUTES'.

2 files changed, 256 insertions, 0 deletions

diff --git a/tests/base64.scm b/tests/base64.scm
new file mode 100644
index 0000000000..99c02b531e
--- /dev/null
+++ b/tests/base64.scm
@@ -0,0 +1,59 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014 Nikita Karetnikov <nikita@karetnikov.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (test-base64)
+  #:use-module (guix base64)
+  #:use-module (rnrs bytevectors)
+  #:use-module (srfi srfi-64))
+
+(define (string->base64 str)
+  (base64-encode (string->utf8 str)))
+
+;;; Test vectors from <https://tools.ietf.org/rfc/rfc4648.txt>.
+
+(test-begin "base64")
+
+(test-equal "empty string"
+  (string->base64 "")
+  "")
+
+(test-equal "f"
+  (string->base64 "f")
+  "Zg==")
+
+(test-equal "fo"
+  (string->base64 "fo")
+  "Zm8=")
+
+(test-equal "foo"
+  (string->base64 "foo")
+  "Zm9v")
+
+(test-equal "foob"
+  (string->base64 "foob")
+  "Zm9vYg==")
+
+(test-equal "fooba"
+  (string->base64 "fooba")
+  "Zm9vYmE=")
+
+(test-equal "foobar"
+  (string->base64 "foobar")
+  "Zm9vYmFy")
+
+(test-end "base64")
\ No newline at end of file
diff --git a/tests/substitute-binary.scm b/tests/substitute-binary.scm
new file mode 100644
index 0000000000..0903b202f2
--- /dev/null
+++ b/tests/substitute-binary.scm
@@ -0,0 +1,197 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014 Nikita Karetnikov <nikita@karetnikov.org>
+;;; Copyright © 2014 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (test-substitute-binary)
+  #:use-module (guix scripts substitute-binary)
+  #:use-module (guix base64)
+  #:use-module (guix hash)
+  #:use-module (guix nar)
+  #:use-module (guix pk-crypto)
+  #:use-module (guix pki)
+  #:use-module (rnrs bytevectors)
+  #:use-module (srfi srfi-34)
+  #:use-module ((srfi srfi-64) #:hide (test-error)))
+
+(define assert-valid-signature
+  ;; (guix scripts substitute-binary) does not export this function in order to
+  ;; avoid misuse.
+  (@@ (guix scripts substitute-binary) assert-valid-signature))
+
+;;; XXX: Replace with 'test-error' from SRFI-64 as soon as it allow us to
+;;; catch specific exceptions.
+(define-syntax-rule (test-error* name exp)
+  (test-assert name
+    (catch 'quit
+      (lambda ()
+        exp
+        #f)
+      (const #t))))
+
+(define %keypair
+  ;; (display (canonical-sexp->string
+  ;;           (generate-key "(genkey (rsa (nbits 4:1024)))")))
+  (string->canonical-sexp
+   "(key-data
+ (public-key
+  (rsa
+   (n #00D74A00F16DD109A8E773291856A4EF9EE2C2D975E0BC207EA24245C9CFE39E32D8BA5442A2720A57E3A9D9E55E596A8B19CB2EF844E5E859362593914BD626433C887FB798AE87E1DA95D372DFC81E220B8802B04CEC818D9B6B4E2108817755AEBAC23D2FD2B0AB82A52FD785194F3C2D7B9327212588DB74D464EEE5DC9F5B#)
+   (e #010001#)
+   )
+  )
+ (private-key
+  (rsa
+   (n #00D74A00F16DD109A8E773291856A4EF9EE2C2D975E0BC207EA24245C9CFE39E32D8BA5442A2720A57E3A9D9E55E596A8B19CB2EF844E5E859362593914BD626433C887FB798AE87E1DA95D372DFC81E220B8802B04CEC818D9B6B4E2108817755AEBAC23D2FD2B0AB82A52FD785194F3C2D7B9327212588DB74D464EEE5DC9F5B#)
+   (e #010001#)
+   (d #40E6D963EF143E9241BC10DE7A785C988C89EB1EC33253A5796AFB38FCC804D015500EC8CBCA0F5E318EE9D660DC19E7774E2E89BFD38379297EA87EFBDAC24BA32EE5339215382B2C89F5A817FD9131CA8E8A0A70D58E26E847AD0C447053671A6B2D7746087DE058A02B17701752B8A36EB414435921615AE7CAA8AC48E451#)
+   (p #00EA88C0C19FE83C09285EF49FF88A1159357FD870031C20F15EF5103FBEB10925299BCA197F7143D6792A1BA7044EDA572EC94FA6B00889F9857216CF5B984403#)
+   (q #00EAFE541EE9E0531255A85CADBEF64D5F679766D7209F521ADD131CF4B7DA9DF5414901342A146EE84FAA1E35EE0D0F6CE3F5F25989C0D1E9FA5B678D78C113C9#)
+   (u #59C80FA2C48181F6855691C9D443619BA46C7648056E081697C370D8096E8EF165122D5E55F8FD6A2DCC404FA8BDCDC1FD20B4D76A433F25E8FD6901EC2DBDAD#)
+   )
+  )
+ )"))
+
+(define %public-key
+  (find-sexp-token %keypair 'public-key))
+
+(define %private-key
+  (find-sexp-token %keypair 'private-key))
+
+(define (signature-body str)
+  (base64-encode
+   (string->utf8
+    (canonical-sexp->string
+     (signature-sexp (bytevector->hash-data (sha256 (string->utf8 str))
+                                            #:key-type 'rsa)
+                     %private-key
+                     %public-key)))))
+
+(define %signature-body
+  (signature-body "secret"))
+
+(define %wrong-public-key
+  (string->canonical-sexp "(public-key
+ (rsa
+  (n #00E05873AC2B168760343145918E954EE9AB73C026355693B192E01EE835261AA689E9EF46642E895BCD65C648524059FC450E4BA77A68F4C52D0E39EF0CC9359709AB6AAB153B63782201871325B0FDA19CB401CD99FD0C31A91CA9000AA90A77E82B89E036FB63BC1D3961207469B3B12468977148D376F8012BB12A4B11A8F1#)
+  (e #010001#)
+  )
+ )"))
+
+(define %wrong-signature
+  (let* ((body (string->canonical-sexp
+                (utf8->string
+                 (base64-decode %signature-body))))
+         (data       (canonical-sexp->string (find-sexp-token body 'data)))
+         (sig-val    (canonical-sexp->string (find-sexp-token body 'sig-val)))
+         (public-key (canonical-sexp->string %wrong-public-key))
+         (body*      (base64-encode
+                      (string->utf8
+                       (string-append "(signature \n" data sig-val
+                                      public-key " )\n")))))
+    (string-append "1;irrelevant;" body*)))
+
+(define* (signature str #:optional (body %signature-body))
+  (string-append str ";irrelevant;" body))
+
+(define %signature
+  (signature "1" %signature-body))
+
+(define %acl
+  (public-keys->acl (list %public-key)))
+
+(test-begin "substitute-binary")
+
+(test-error* "not a number"
+  (narinfo-signature->canonical-sexp (signature "not a number")))
+
+(test-error* "wrong version number"
+  (narinfo-signature->canonical-sexp (signature "2")))
+
+(test-assert "valid narinfo-signature->canonical-sexp"
+  (canonical-sexp? (narinfo-signature->canonical-sexp %signature)))
+
+(define-syntax-rule (test-error-condition name pred exp)
+  (test-assert name
+    (guard (condition ((pred condition) (pk 'true condition #t))
+                      (else #f))
+      exp
+      #f)))
+
+;;; XXX: Do we need a better predicate hierarchy for these tests?
+(test-error-condition "corrupt signature data"
+  nar-signature-error?
+  (assert-valid-signature "invalid sexp" "irrelevant"
+                          (open-input-string "irrelevant")
+                          %acl))
+
+(test-error-condition "unauthorized public key"
+  nar-signature-error?
+  (assert-valid-signature (canonical-sexp->string
+                           (narinfo-signature->canonical-sexp %signature))
+                          "irrelevant"
+                          (open-input-string "irrelevant")
+                          (public-keys->acl '())))
+
+(test-error-condition "invalid signature"
+  nar-signature-error?
+  (assert-valid-signature (canonical-sexp->string
+                           (narinfo-signature->canonical-sexp
+                            %wrong-signature))
+                          (sha256 (string->utf8 "secret"))
+                          (open-input-string "irrelevant")
+                          (public-keys->acl (list %wrong-public-key))))
+
+(define %narinfo
+  "StorePath: /nix/store/foo
+URL: nar/foo
+Compression: bzip2
+NarHash: sha256:7
+NarSize: 42
+References: bar baz
+Deriver: foo.drv
+System: mips64el-linux\n")
+
+(define (narinfo sig)
+  (format #f "~aSignature: ~a~%" %narinfo sig))
+
+(define %signed-narinfo
+  (narinfo (signature "1" (signature-body %narinfo))))
+
+(test-error-condition "invalid hash"
+  ;; The hash of '%signature' is computed over the word "secret", not
+  ;; '%narinfo'.
+  nar-invalid-hash-error?
+  (read-narinfo (open-input-string (narinfo %signature))
+                "https://example.com" %acl))
+
+(test-assert "valid read-narinfo"
+  (read-narinfo (open-input-string %signed-narinfo)
+                "https://example.com" %acl))
+
+(test-equal "valid write-narinfo"
+  %signed-narinfo
+  (call-with-output-string
+   (lambda (port)
+     (write-narinfo (read-narinfo (open-input-string %signed-narinfo)
+                                  "https://example.com" %acl)
+                    port))))
+
+(test-end "substitute-binary")
+
+
+(exit (= (test-runner-fail-count (test-runner-current)) 0))