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From:   Tong Zhang <ztong@vt.edu>
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Subject: Leaking path for search_binary_handler
Message-Id: <C2D9C687-4964-4DB3-AAF4-7C836324D6BE@vt.edu>
Date:   Tue, 25 Sep 2018 13:27:03 -0400
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org, wenbo.s@samsung.com
To:     viro@zeniv.linux.org.uk
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Kernel Version: 4.18.5

Problem Description:

search_binary_handler() should be called after setting bprm using prepare_binprm(),
and in prepare_binprm(), there’s a LSM hook security_bprm_set_creds(), 
which can make a decision that binfmt cares.

We found a leaking path In fs/binfmt_misc.c:235, that don’t ask LSM’s decision.

- Tong