common,gpg,sm: Restrict the use of algorithms according to CO_DE_VS.

* common/compliance.c (gnupg_pk_is_allowed): New function.
(gnupg_cipher_is_allowed): Likewise.
(gnupg_digest_is_allowed): Likewise.
* common/compliance.h (enum pk_use_case): New definition.
(gnupg_pk_is_allowed): New prototype.
(gnupg_cipher_is_allowed): Likewise.
(gnupg_digest_is_allowed): Likewise.
* g10/decrypt-data.c (decrypt_data): Restrict use of algorithms using
the new predicates.
* g10/encrypt.c (encrypt_crypt): Likewise.
* g10/gpg.c (main): Likewise.
* g10/pubkey-enc.c (get_session_key): Likewise.
* g10/sig-check.c (check_signature2): Likewise.
* g10/sign.c (do_sign): Likewise.
* sm/decrypt.c (gpgsm_decrypt): Likewise.
* sm/encrypt.c (gpgsm_encrypt): Likewise.
* sm/gpgsm.c (main): Likewise.
* sm/sign.c (gpgsm_sign): Likewise.
* sm/verify.c (gpgsm_verify): Likewise.
--

With this change, policies can effectively restrict what algorithms
are used for different purposes.  The algorithm policy for CO_DE_VS is
implemented.

GnuPG-bug-id: 3191
Signed-off-by: Justus Winter <justus@g10code.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/sm/gpgsm.c b/sm/gpgsm.c
index f749cfd28..c462544e2 100644
--- a/sm/gpgsm.c
+++ b/sm/gpgsm.c
@@ -1614,6 +1614,43 @@ main ( int argc, char **argv)
         }
     }
 
+  /* Check our chosen algorithms against the list of allowed
+   * algorithms in the current compliance mode, and fail hard if it is
+   * not.  This is us being nice to the user informing her early that
+   * the chosen algorithms are not available.  We also check and
+   * enforce this right before the actual operation.  */
+  if (! gnupg_cipher_is_allowed (opt.compliance,
+                                 cmd == aEncr || cmd == aSignEncr,
+                                 gcry_cipher_map_name (opt.def_cipher_algoid),
+                                 GCRY_CIPHER_MODE_NONE)
+      && ! gnupg_cipher_is_allowed (opt.compliance,
+                                    cmd == aEncr || cmd == aSignEncr,
+                                    gcry_cipher_mode_from_oid (opt.def_cipher_algoid),
+                                    GCRY_CIPHER_MODE_NONE))
+    log_error (_ ("you may not use cipher algorithm '%s'"
+                  " while in %s mode\n"),
+               opt.def_cipher_algoid, gnupg_compliance_option_string (opt.compliance));
+
+  if (forced_digest_algo
+      && ! gnupg_digest_is_allowed (opt.compliance,
+                                     cmd == aSign
+                                     || cmd == aSignEncr
+                                     || cmd == aClearsign,
+                                     opt.forced_digest_algo))
+    log_error (_ ("you may not use digest algorithm '%s'"
+                  " while in %s mode\n"),
+               forced_digest_algo, gnupg_compliance_option_string (opt.compliance));
+
+  if (extra_digest_algo
+      && ! gnupg_digest_is_allowed (opt.compliance,
+                                     cmd == aSign
+                                     || cmd == aSignEncr
+                                     || cmd == aClearsign,
+                                     opt.extra_digest_algo))
+    log_error (_ ("you may not use digest algorithm '%s'"
+                  " while in %s mode\n"),
+               forced_digest_algo, gnupg_compliance_option_string (opt.compliance));
+
   if (log_get_errorcount(0))
     gpgsm_exit(2);