Description of problem:
in crypto/signature/ksign.c, ksign_signature_check() checks if the
return value of ksign_get_public_key() was null.  Unfortunately, it is
possible for ksign_get_public_key() to return a bogus non-null pointer if
the key is not actually found.  This results in (at best) a 'atomic counter
underflow' complaint from ksign_put_public_key (because it dereferences
pk->count), and at worst locking failures and similar


Version-Release number of selected component (if applicable):
2.6.13-1.1627_FC5

How reproducible:
Attempt to modprobe a module that is signed with a key other than the one that's
in crypto/signatures/key.h

Steps to Reproduce:
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Actual results:


Expected results:


Additional info:
Patch to make ksign_get_public_key() to behave nicely attached....