smb: client: reject userspace cifs.spnego descriptions#291
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cifs.spnego key descriptions contain authority-bearing fields such as pid, uid, creduid, and upcall_target that cifs.upcall treats as kernel-originating inputs. However, userspace can also create keys of this type through request_key(2) or add_key(2), allowing those fields to be supplied without CIFS origin. Only accept cifs.spnego descriptions while CIFS is using its private spnego_cred to request the key. Fixes: f1d662a ("[CIFS] Add upcall files for cifs to use spnego/kerberos") Assisted-by: avom-custom-harness:gpt-5.5-qwen3.6-mod-mix Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Asim Viladi Oglu Manizada <manizada@pm.me> Signed-off-by: Steve French <stfrench@microsoft.com>
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#283 is already present in the
release/25.10.4branch; this is just a minor backport to keep both branches in sync.cifs.spnego key descriptions contain authority-bearing fields such as pid, uid, creduid, and upcall_target that cifs.upcall treats as kernel-originating inputs. However, userspace can also create keys of this type through request_key(2) or add_key(2), allowing those fields to be supplied without CIFS origin.
Only accept cifs.spnego descriptions while CIFS is using its private spnego_cred to request the key.
Fixes: f1d662a ("[CIFS] Add upcall files for cifs to use spnego/kerberos")
Assisted-by: avom-custom-harness:gpt-5.5-qwen3.6-mod-mix
Reviewed-by: David Howells dhowells@redhat.com