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Diffstat (limited to 'guix/pk-crypto.scm')
| -rw-r--r-- | guix/pk-crypto.scm | 407 |
1 files changed, 0 insertions, 407 deletions
diff --git a/guix/pk-crypto.scm b/guix/pk-crypto.scm deleted file mode 100644 index 55ba7b1bb8..0000000000 --- a/guix/pk-crypto.scm +++ /dev/null @@ -1,407 +0,0 @@ -;;; GNU Guix --- Functional package management for GNU -;;; Copyright © 2013, 2014, 2015, 2017 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 (guix pk-crypto) - #:use-module (guix base16) - #:use-module (guix gcrypt) - - #:use-module (system foreign) - #:use-module (rnrs bytevectors) - #:use-module (ice-9 match) - #:use-module (ice-9 rdelim) - #:export (canonical-sexp? - error-source - error-string - string->canonical-sexp - canonical-sexp->string - read-file-sexp - number->canonical-sexp - canonical-sexp-car - canonical-sexp-cdr - canonical-sexp-nth - canonical-sexp-nth-data - canonical-sexp-length - canonical-sexp-null? - canonical-sexp-list? - bytevector->hash-data - hash-data->bytevector - key-type - sign - verify - generate-key - find-sexp-token - canonical-sexp->sexp - sexp->canonical-sexp) - #:re-export (gcrypt-version)) - - -;;; Commentary: -;;; -;;; Public key cryptographic routines from GNU Libgcrypt. -;;;; -;;; Libgcrypt uses "canonical s-expressions" to represent key material, -;;; parameters, and data. We keep it as an opaque object to map them to -;;; Scheme s-expressions because (1) Libgcrypt sexps may be stored in secure -;;; memory, and (2) the read syntax is different. -;;; -;;; A 'canonical-sexp->sexp' procedure is provided nevertheless, for use in -;;; cases where it is safe to move data out of Libgcrypt---e.g., when -;;; processing ACL entries, public keys, etc. -;;; -;;; Canonical sexps were defined by Rivest et al. in the IETF draft at -;;; <http://people.csail.mit.edu/rivest/Sexp.txt> for the purposes of SPKI -;;; (see <http://www.ietf.org/rfc/rfc2693.txt>.) -;;; -;;; Code: - -;; Libgcrypt "s-expressions". -(define-wrapped-pointer-type <canonical-sexp> - canonical-sexp? - naked-pointer->canonical-sexp - canonical-sexp->pointer - (lambda (obj port) - ;; Don't print OBJ's external representation: we don't want key material - ;; to leak in backtraces and such. - (format port "#<canonical-sexp ~a | ~a>" - (number->string (object-address obj) 16) - (number->string (pointer-address (canonical-sexp->pointer obj)) - 16)))) - -(define finalize-canonical-sexp! - (libgcrypt-func "gcry_sexp_release")) - -(define-inlinable (pointer->canonical-sexp ptr) - "Return a <canonical-sexp> that wraps PTR." - (let* ((sexp (naked-pointer->canonical-sexp ptr)) - (ptr* (canonical-sexp->pointer sexp))) - ;; Did we already have a <canonical-sexp> object for PTR? - (when (equal? ptr ptr*) - ;; No, so we can safely add a finalizer (in Guile 2.0.9 - ;; 'set-pointer-finalizer!' *adds* a finalizer rather than replacing the - ;; existing one.) - (set-pointer-finalizer! ptr finalize-canonical-sexp!)) - sexp)) - -(define error-source - (let* ((ptr (libgcrypt-func "gcry_strsource")) - (proc (pointer->procedure '* ptr (list int)))) - (lambda (err) - "Return the error source (a string) for ERR, an error code as thrown -along with 'gcry-error'." - (pointer->string (proc err))))) - -(define error-string - (let* ((ptr (libgcrypt-func "gcry_strerror")) - (proc (pointer->procedure '* ptr (list int)))) - (lambda (err) - "Return the error description (a string) for ERR, an error code as -thrown along with 'gcry-error'." - (pointer->string (proc err))))) - -(define string->canonical-sexp - (let* ((ptr (libgcrypt-func "gcry_sexp_new")) - (proc (pointer->procedure int ptr `(* * ,size_t ,int)))) - (lambda (str) - "Parse STR and return the corresponding gcrypt s-expression." - - ;; When STR comes from 'canonical-sexp->string', it may contain - ;; characters that are really meant to be interpreted as bytes as in a C - ;; 'char *'. Thus, convert STR to ISO-8859-1 so the byte values of the - ;; characters are preserved. - (let* ((sexp (bytevector->pointer (make-bytevector (sizeof '*)))) - (err (proc sexp (string->pointer str "ISO-8859-1") 0 1))) - (if (= 0 err) - (pointer->canonical-sexp (dereference-pointer sexp)) - (throw 'gcry-error 'string->canonical-sexp err)))))) - -(define-syntax GCRYSEXP_FMT_ADVANCED - (identifier-syntax 3)) - -(define canonical-sexp->string - (let* ((ptr (libgcrypt-func "gcry_sexp_sprint")) - (proc (pointer->procedure size_t ptr `(* ,int * ,size_t)))) - (lambda (sexp) - "Return a textual representation of SEXP." - (let loop ((len 1024)) - (let* ((buf (bytevector->pointer (make-bytevector len))) - (size (proc (canonical-sexp->pointer sexp) - GCRYSEXP_FMT_ADVANCED buf len))) - (if (zero? size) - (loop (* len 2)) - (pointer->string buf size "ISO-8859-1"))))))) - -(define (read-file-sexp file) - "Return the canonical sexp read from FILE." - (call-with-input-file file - (compose string->canonical-sexp - read-string))) - -(define canonical-sexp-car - (let* ((ptr (libgcrypt-func "gcry_sexp_car")) - (proc (pointer->procedure '* ptr '(*)))) - (lambda (lst) - "Return the first element of LST, an sexp, if that element is a list; -return #f if LST or its first element is not a list (this is different from -the usual Lisp 'car'.)" - (let ((result (proc (canonical-sexp->pointer lst)))) - (if (null-pointer? result) - #f - (pointer->canonical-sexp result)))))) - -(define canonical-sexp-cdr - (let* ((ptr (libgcrypt-func "gcry_sexp_cdr")) - (proc (pointer->procedure '* ptr '(*)))) - (lambda (lst) - "Return the tail of LST, an sexp, or #f if LST is not a list." - (let ((result (proc (canonical-sexp->pointer lst)))) - (if (null-pointer? result) - #f - (pointer->canonical-sexp result)))))) - -(define canonical-sexp-nth - (let* ((ptr (libgcrypt-func "gcry_sexp_nth")) - (proc (pointer->procedure '* ptr `(* ,int)))) - (lambda (lst index) - "Return the INDEXth nested element of LST, an s-expression. Return #f -if that element does not exist, or if it's an atom. (Note: this is obviously -different from Scheme's 'list-ref'.)" - (let ((result (proc (canonical-sexp->pointer lst) index))) - (if (null-pointer? result) - #f - (pointer->canonical-sexp result)))))) - -(define (dereference-size_t p) - "Return the size_t value pointed to by P." - (bytevector-uint-ref (pointer->bytevector p (sizeof size_t)) - 0 (native-endianness) - (sizeof size_t))) - -(define canonical-sexp-length - (let* ((ptr (libgcrypt-func "gcry_sexp_length")) - (proc (pointer->procedure int ptr '(*)))) - (lambda (sexp) - "Return the length of SEXP if it's a list (including the empty list); -return zero if SEXP is an atom." - (proc (canonical-sexp->pointer sexp))))) - -(define token-string? - (let ((token-cs (char-set-union char-set:digit - char-set:letter - (char-set #\- #\. #\/ #\_ - #\: #\* #\+ #\=)))) - (lambda (str) - "Return #t if STR is a token as per Section 4.3 of -<http://people.csail.mit.edu/rivest/Sexp.txt>." - (and (not (string-null? str)) - (string-every token-cs str) - (not (char-set-contains? char-set:digit (string-ref str 0))))))) - -(define canonical-sexp-nth-data - (let* ((ptr (libgcrypt-func "gcry_sexp_nth_data")) - (proc (pointer->procedure '* ptr `(* ,int *)))) - (lambda (lst index) - "Return as a symbol (for \"sexp tokens\") or a bytevector (for any other -\"octet string\") the INDEXth data element (atom) of LST, an s-expression. -Return #f if that element does not exist, or if it's a list." - (let* ((size* (bytevector->pointer (make-bytevector (sizeof '*)))) - (result (proc (canonical-sexp->pointer lst) index size*))) - (if (null-pointer? result) - #f - (let* ((len (dereference-size_t size*)) - (str (pointer->string result len "ISO-8859-1"))) - ;; The sexp spec speaks of "tokens" and "octet strings". - ;; Sometimes these octet strings are actual strings (text), - ;; sometimes they're bytevectors, and sometimes they're - ;; multi-precision integers (MPIs). Only the application knows. - ;; However, for convenience, we return a symbol when a token is - ;; encountered since tokens are frequent (at least in the 'car' - ;; of each sexp.) - (if (token-string? str) - (string->symbol str) ; an sexp "token" - (bytevector-copy ; application data, textual or binary - (pointer->bytevector result len))))))))) - -(define (number->canonical-sexp number) - "Return an s-expression representing NUMBER." - (string->canonical-sexp (string-append "#" (number->string number 16) "#"))) - -(define* (bytevector->hash-data bv - #:optional - (hash-algo "sha256") - #:key (key-type 'ecc)) - "Given BV, a bytevector containing a hash of type HASH-ALGO, return an -s-expression suitable for use as the 'data' argument for 'sign'. KEY-TYPE -must be a symbol: 'dsa, 'ecc, or 'rsa." - (string->canonical-sexp - (format #f "(data (flags ~a) (hash \"~a\" #~a#))" - (case key-type - ((ecc dsa) "rfc6979") - ((rsa) "pkcs1") - (else (error "unknown key type" key-type))) - hash-algo - (bytevector->base16-string bv)))) - -(define (key-type sexp) - "Return a symbol denoting the type of public or private key represented by -SEXP--e.g., 'rsa', 'ecc'--or #f if SEXP does not denote a valid key." - (case (canonical-sexp-nth-data sexp 0) - ((public-key private-key) - (canonical-sexp-nth-data (canonical-sexp-nth sexp 1) 0)) - (else #f))) - -(define* (hash-data->bytevector data) - "Return two values: the hash value (a bytevector), and the hash algorithm (a -string) extracted from DATA, an sexp as returned by 'bytevector->hash-data'. -Return #f if DATA does not conform." - (let ((hash (find-sexp-token data 'hash))) - (if hash - (let ((algo (canonical-sexp-nth-data hash 1)) - (value (canonical-sexp-nth-data hash 2))) - (values value (symbol->string algo))) - (values #f #f)))) - -(define sign - (let* ((ptr (libgcrypt-func "gcry_pk_sign")) - (proc (pointer->procedure int ptr '(* * *)))) - (lambda (data secret-key) - "Sign DATA, a canonical s-expression representing a suitable hash, with -SECRET-KEY (a canonical s-expression whose car is 'private-key'.) Note that -DATA must be a 'data' s-expression, as returned by -'bytevector->hash-data' (info \"(gcrypt) Cryptographic Functions\")." - (let* ((sig (bytevector->pointer (make-bytevector (sizeof '*)))) - (err (proc sig (canonical-sexp->pointer data) - (canonical-sexp->pointer secret-key)))) - (if (= 0 err) - (pointer->canonical-sexp (dereference-pointer sig)) - (throw 'gcry-error 'sign err)))))) - -(define verify - (let* ((ptr (libgcrypt-func "gcry_pk_verify")) - (proc (pointer->procedure int ptr '(* * *)))) - (lambda (signature data public-key) - "Verify that SIGNATURE is a signature of DATA with PUBLIC-KEY, all of -which are gcrypt s-expressions." - (zero? (proc (canonical-sexp->pointer signature) - (canonical-sexp->pointer data) - (canonical-sexp->pointer public-key)))))) - -(define generate-key - (let* ((ptr (libgcrypt-func "gcry_pk_genkey")) - (proc (pointer->procedure int ptr '(* *)))) - (lambda (params) - "Return as an s-expression a new key pair for PARAMS. PARAMS must be an -s-expression like: (genkey (rsa (nbits 4:2048)))." - (let* ((key (bytevector->pointer (make-bytevector (sizeof '*)))) - (err (proc key (canonical-sexp->pointer params)))) - (if (zero? err) - (pointer->canonical-sexp (dereference-pointer key)) - (throw 'gcry-error 'generate-key err)))))) - -(define find-sexp-token - (let* ((ptr (libgcrypt-func "gcry_sexp_find_token")) - (proc (pointer->procedure '* ptr `(* * ,size_t)))) - (lambda (sexp token) - "Find in SEXP the first element whose 'car' is TOKEN and return it; -return #f if not found." - (let* ((token (string->pointer (symbol->string token))) - (res (proc (canonical-sexp->pointer sexp) token 0))) - (if (null-pointer? res) - #f - (pointer->canonical-sexp res)))))) - -(define-inlinable (canonical-sexp-null? sexp) - "Return #t if SEXP is the empty-list sexp." - (null-pointer? (canonical-sexp->pointer sexp))) - -(define (canonical-sexp-list? sexp) - "Return #t if SEXP is a list." - (or (canonical-sexp-null? sexp) - (> (canonical-sexp-length sexp) 0))) - -(define (canonical-sexp-fold proc seed sexp) - "Fold PROC (as per SRFI-1) over SEXP, a canonical sexp." - (if (canonical-sexp-list? sexp) - (let ((len (canonical-sexp-length sexp))) - (let loop ((index 0) - (result seed)) - (if (= index len) - result - (loop (+ 1 index) - ;; XXX: Call 'nth-data' *before* 'nth' to work around - ;; <https://bugs.g10code.com/gnupg/issue1594>, which - ;; affects 1.6.0 and earlier versions. - (proc (or (canonical-sexp-nth-data sexp index) - (canonical-sexp-nth sexp index)) - result))))) - (error "sexp is not a list" sexp))) - -(define (canonical-sexp->sexp sexp) - "Return a Scheme sexp corresponding to SEXP. This is particularly useful to -compare sexps (since Libgcrypt does not provide an 'equal?' procedure), or to -use pattern matching." - (if (canonical-sexp-list? sexp) - (reverse - (canonical-sexp-fold (lambda (item result) - (cons (if (canonical-sexp? item) - (canonical-sexp->sexp item) - item) - result)) - '() - sexp)) - - ;; As of Libgcrypt 1.6.0, there's no function to extract the buffer of a - ;; non-list sexp (!), so we first enlist SEXP, then get at its buffer. - (let ((sexp (string->canonical-sexp - (string-append "(" (canonical-sexp->string sexp) - ")")))) - (or (canonical-sexp-nth-data sexp 0) - (canonical-sexp-nth sexp 0))))) - -(define (sexp->canonical-sexp sexp) - "Return a canonical sexp equivalent to SEXP, a Scheme sexp as returned by -'canonical-sexp->sexp'." - ;; XXX: This is inefficient, but the Libgcrypt API doesn't allow us to do - ;; much better. - (string->canonical-sexp - (call-with-output-string - (lambda (port) - (define (write item) - (cond ((list? item) - (display "(" port) - (for-each write item) - (display ")" port)) - ((symbol? item) - (format port " ~a" item)) - ((bytevector? item) - (format port " #~a#" - (bytevector->base16-string item))) - (else - (error "unsupported sexp item type" item)))) - - (write sexp))))) - -(define (gcrypt-error-printer port key args default-printer) - "Print the gcrypt error specified by ARGS." - (match args - ((proc err) - (format port "In procedure ~a: ~a: ~a" - proc (error-source err) (error-string err))))) - -(set-exception-printer! 'gcry-error gcrypt-error-printer) - -;;; pk-crypto.scm ends here |