* certlist.c (cert_usable_p): New.

(gpgsm_cert_use_sign_p,gpgsm_cert_use_encrypt_p): New.
(gpgsm_cert_use_verify_p,gpgsm_cert_use_decrypt_p): New.
(gpgsm_add_to_certlist): Check the key usage.
* sign.c (gpgsm_sign): Ditto.
* verify.c (gpgsm_verify): Print a message wehn an unsuitable
certificate was used.
* decrypt.c (gpgsm_decrypt): Ditto
* keylist.c (print_capabilities): Determine values from the cert.

1 files changed, 4 insertions, 0 deletions

diff --git a/sm/sign.c b/sm/sign.c
index b16e840bc..2781baa84 100644
--- a/sm/sign.c
+++ b/sm/sign.c
@@ -310,6 +310,10 @@ gpgsm_sign (CTRL ctrl, int data_fd, int detached, FILE *out_fp)
       rc = seterr (General_Error);
       goto leave;
     }
+  rc = gpgsm_cert_use_sign_p (cert);
+  if (rc)
+    goto leave;
+
   err = ksba_cms_add_signer (cms, cert);
   if (err)
     {