gpg: Prepare revocation keys for use with v5 keys.

* g10/packet.h (struct revocation_key): Add field 'fprlen'.
* g10/parse-packet.c (parse_revkeys): Set fprlen and allow for v5
keys.  Also fix reading of unitialized data at place where
MAX_FINGERPRINT_LEN is used.
* g10/revoke.c (gen_desig_revoke): Allow for v5 keys and use fprlen.
Do an explicit compare to avoid reading unitialized data.
* g10/sig-check.c (check_revocation_keys): Use the fprlen.
* g10/getkey.c (merge_selfsigs_main): Do an explicit copy to avoid
reading unitialized data.
* g10/import.c (revocation_present): Use fprlen.
* g10/keyedit.c (show_key_with_all_names): Use fprlen.
(menu_addrevoker): Use fprlen.  Allow for v5 keys.
* g10/keygen.c (keygen_add_revkey): Use fprlen.
(parse_revocation_key): Allow for v5 keys.
* g10/keyid.c (keyid_from_fingerprint): Allow for v5 keys.  Print a
better error message in case of bogus fingerprints.
* g10/keylist.c (print_revokers): Use fprlen.
--

The reading of uninitialized data is harmless but we better fix it to
make valgrind happy.  More serious was that we always passed
MAX_FINGERPRINT_LEN but we will need to support 20 and 32 octet
fingerprints and MAX_FINGERPRINT_LEN would be too large for a v4.

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 7 insertions, 3 deletions

diff --git a/g10/keygen.c b/g10/keygen.c
index 145b871b0..61f839a9f 100644
--- a/g10/keygen.c
+++ b/g10/keygen.c
@@ -943,11 +943,13 @@ keygen_add_revkey (PKT_signature *sig, void *opaque)
   struct revocation_key *revkey = opaque;
   byte buf[2+MAX_FINGERPRINT_LEN];
 
+  log_assert (revkey->fprlen <= MAX_FINGERPRINT_LEN);
   buf[0] = revkey->class;
   buf[1] = revkey->algid;
-  memcpy (&buf[2], revkey->fpr, MAX_FINGERPRINT_LEN);
+  memcpy (buf + 2, revkey->fpr, revkey->fprlen);
+  memset (buf + 2 + revkey->fprlen, 0, sizeof (revkey->fpr) - revkey->fprlen);
 
-  build_sig_subpkt (sig, SIGSUBPKT_REV_KEY, buf, 2+MAX_FINGERPRINT_LEN);
+  build_sig_subpkt (sig, SIGSUBPKT_REV_KEY, buf, 2+revkey->fprlen);
 
   /* All sigs with revocation keys set are nonrevocable.  */
   sig->flags.revocable = 0;
@@ -3526,6 +3528,8 @@ parse_revocation_key (const char *fname,
 
       revkey.fpr[i]=c;
     }
+  if (i != 20 && i != 32)
+    goto fail;
 
   /* skip to the tag */
   while(*pn && *pn!='s' && *pn!='S')
@@ -3538,7 +3542,7 @@ parse_revocation_key (const char *fname,
 
   return 0;
 
-  fail:
+ fail:
   log_error("%s:%d: invalid revocation key\n", fname, r->lnr );
   return -1; /* error */
 }