gpg: Ensure all weak digest rejection notices are shown

* g10/main.h: Add rejection_shown flag to each weakhash struct
* g10/misc.c (print_digest_algo_note, additional_weak_digest): Do not
treat MD5 separately; (print_digest_rejected_note): Use
weakhash.rejection_shown instead of static shown.
* g10/options.h (opt): Change from additional_weak_digests to
weak_digests.
* g10/sig-check.c: Do not treat MD5 separately.
* g10/gpg.c (main): Explicitly set MD5 as weak.
* g10/gpgv.c (main): Explicitly set MD5 as weak.

--

Previously, only one weak digest rejection message was shown, of
whichever was the first type encountered.  This meant that if "gpg
--weak-digest SHA224" encountered both an MD5 digest and a SHA224
digest, it would only show the user that the MD5 digest was rejected.

In order to let the user know which algorithms were rejected, we
needed to move the "shown" flag into a per-weak-algorithm location.
Given this additional complication, it made no sense to continue to
treat MD5 specially, so it is added as a default weak algorithm in the
same opt.weak_digests data structure as any other.

Signed-Off-By: Daniel Kahn Gillmor <[email protected]>

1 files changed, 25 insertions, 26 deletions

diff --git a/g10/misc.c b/g10/misc.c
index 93ddaa042..5c77714d3 100644
--- a/g10/misc.c
+++ b/g10/misc.c
@@ -307,7 +307,6 @@ print_cipher_algo_note (cipher_algo_t algo)
 void
 print_digest_algo_note (digest_algo_t algo)
 {
-  int deprecated = 0;
   const enum gcry_md_algos galgo = map_md_openpgp_to_gcry (algo);
   const struct weakhash *weak;
 
@@ -322,34 +321,38 @@ print_digest_algo_note (digest_algo_t algo)
                     gcry_md_algo_name (galgo));
 	}
     }
-  else if(algo == DIGEST_ALGO_MD5)
-    deprecated = 1;
   else
-      for (weak = opt.additional_weak_digests; weak != NULL; weak = weak->next)
+      for (weak = opt.weak_digests; weak != NULL; weak = weak->next)
         if (weak->algo == galgo)
-          deprecated = 1;
-
-  if (deprecated)
-    {
-      es_fflush (es_stdout);
-      log_info (_("WARNING: digest algorithm %s is deprecated\n"),
-                gcry_md_algo_name (galgo));
-    }
+          {
+            es_fflush (es_stdout);
+            log_info (_("WARNING: digest algorithm %s is deprecated\n"),
+                      gcry_md_algo_name (galgo));
+          }
 }
 
 
 void
 print_digest_rejected_note (enum gcry_md_algos algo)
 {
-  static int shown;
-
-  if (!shown)
+  struct weakhash* weak;
+  int show = 1;
+  for (weak = opt.weak_digests; weak; weak = weak->next)
+    if (weak->algo == algo)
+      {
+        if (weak->rejection_shown)
+          show = 0;
+        else
+          weak->rejection_shown = 1;
+        break;
+      }
+
+  if (show)
     {
       es_fflush (es_stdout);
       log_info
         (_("Note: signatures using the %s algorithm are rejected\n"),
          gcry_md_algo_name(algo));
-      shown = 1;
     }
 }
 
@@ -1699,9 +1702,6 @@ additional_weak_digest (const char* digestname)
   struct weakhash *weak = NULL;
   const enum gcry_md_algos algo = string_to_digest_algo(digestname);
 
-  if (algo == GCRY_MD_MD5)
-    return; /* MD5 is always considered weak, no need to add it.  */
-
   if (algo == GCRY_MD_NONE)
     {
       log_error(_("Unknown weak digest '%s'\n"), digestname);
@@ -1709,15 +1709,14 @@ additional_weak_digest (const char* digestname)
     }
 
   /* Check to ensure it's not already present.  */
-  for (weak = opt.additional_weak_digests; weak != NULL; weak = weak->next)
-    {
-      if (algo == weak->algo)
-        return;
-    }
+  for (weak = opt.weak_digests; weak; weak = weak->next)
+    if (algo == weak->algo)
+      return;
 
   /* Add it to the head of the list.  */
   weak = xmalloc(sizeof(*weak));
   weak->algo = algo;
-  weak->next = opt.additional_weak_digests;
-  opt.additional_weak_digests = weak;
+  weak->rejection_shown = 0;
+  weak->next = opt.weak_digests;
+  opt.weak_digests = weak;
 }