bug#37420: [PATCH] Recommend against SHA-1 for security-related applications

[Stefan Kangas <stefan@marxist.se>]

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Robert Pluim <rpluim@gmail.com> writes:

> >>>>> On Tue, 17 Sep 2019 09:05:09 +0300, Eli Zaretskii <eliz@gnu.org> said:
>
>     >> From: Stefan Kangas <stefan@marxist.se>
>     >> Date: Mon, 16 Sep 2019 23:50:33 +0200
>     >> Cc: 37420@debbugs.gnu.org
>     >>
>     >> +These symbols corresponds to the following hashing algorithms:
>     >> +
>     >> +    md5    - MD5
>     >> +    sha1   - SHA-1
>     >> +    sha224 - SHA-2 / SHA-224
>     >> +    sha256 - SHA-2 / SHA-384
>     >> +    sha384 - SHA-2 / SHA-384
>     >> +    sha512 - SHA-2 / SHA-512
>
>     Eli> Please always use "--" to imply an em-dash in plain text.  In this
>     Eli> case, perhaps an even better way would be to explicitly say
>     Eli> "corresponds to".
>
> You have sha256 -> SHA-384

Thanks Eli and Robert.  How about the attached patch?

Best regards,
Stefan Kangas

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From 63457d19d76f11797d455408ba840d8c04a9458e Mon Sep 17 00:00:00 2001
From: Stefan Kangas <stefankangas@gmail.com>
Date: Mon, 16 Sep 2019 23:42:56 +0200
Subject: [PATCH] Add tests for secure-hash and improve doc string

* src/fns.c (Fsecure_hash_algorithms): Fix typo.
(Fsecure_hash): Add algorithm list to doc string.
* test/src/fns-tests.el (test-secure-hash): New test.
---
 src/fns.c             |  9 +++++++--
 test/src/fns-tests.el | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/fns.c b/src/fns.c
index b800f1c47f..fa52e5e197 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -5081,7 +5081,7 @@ make_digest_string (Lisp_Object digest, int digest_size)
 
 DEFUN ("secure-hash-algorithms", Fsecure_hash_algorithms,
        Ssecure_hash_algorithms, 0, 0, 0,
-       doc: /* Return a list of all the supported `secure_hash' algorithms. */)
+       doc: /* Return a list of all the supported `secure-hash' algorithms. */)
   (void)
 {
   return list (Qmd5, Qsha1, Qsha224, Qsha256, Qsha384, Qsha512);
@@ -5388,7 +5388,12 @@ DEFUN ("md5", Fmd5, Smd5, 1, 5, 0,
 DEFUN ("secure-hash", Fsecure_hash, Ssecure_hash, 2, 5, 0,
        doc: /* Return the secure hash of OBJECT, a buffer or string.
 ALGORITHM is a symbol specifying the hash to use:
-md5, sha1, sha224, sha256, sha384 or sha512.
+- md5    corresponds to MD5
+- sha1   corresponds to SHA-1
+- sha224 corresponds to SHA-2 (SHA-224)
+- sha256 corresponds to SHA-2 (SHA-256)
+- sha384 corresponds to SHA-2 (SHA-384)
+- sha512 corresponds to SHA-2 (SHA-512)
 
 The two optional arguments START and END are positions specifying for
 which part of OBJECT to compute the hash.  If nil or omitted, uses the
diff --git a/test/src/fns-tests.el b/test/src/fns-tests.el
index 7d56da77cf..5be9a9eb7b 100644
--- a/test/src/fns-tests.el
+++ b/test/src/fns-tests.el
@@ -858,4 +858,19 @@ test-hash-function-that-mutates-hash-table
        (puthash k k h)))
     (should (= 100 (hash-table-count h)))))
 
+(ert-deftest test-secure-hash ()
+  (should (equal (secure-hash 'md5    "foobar") "3858f62230ac3c915f300c664312c63f"))
+  (should (equal (secure-hash 'sha1   "foobar") "8843d7f92416211de9ebb963ff4ce28125932878"))
+  (should (equal (secure-hash 'sha224 "foobar") (concat "de76c3e567fca9d246f5f8d3b2e704a3"
+                                                        "8c3c5e258988ab525f941db8")))
+  (should (equal (secure-hash 'sha256 "foobar") (concat "c3ab8ff13720e8ad9047dd39466b3c89"
+                                                        "74e592c2fa383d4a3960714caef0c4f2")))
+  (should (equal (secure-hash 'sha384 "foobar") (concat "3c9c30d9f665e74d515c842960d4a451"
+                                                        "c83a0125fd3de7392d7b37231af10c72"
+                                                        "ea58aedfcdf89a5765bf902af93ecf06")))
+  (should (equal (secure-hash 'sha512 "foobar") (concat "0a50261ebd1a390fed2bf326f2673c14"
+                                                        "5582a6342d523204973d0219337f8161"
+                                                        "6a8069b012587cf5635f6925f1b56c36"
+                                                        "0230c19b273500ee013e030601bf2425"))))
+
 (provide 'fns-tests)
-- 
2.20.1