Re: Leaking path for search_binary_handler

From: Stephen Smalley
Date: Wed Sep 26 2018 - 08:57:42 EST


On 09/25/2018 01:27 PM, Tong Zhang wrote:
Kernel Version: 4.18.5

Problem Description:

search_binary_handler() should be called after setting bprm using prepare_binprm(),
and in prepare_binprm(), thereâs 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 donât ask LSMâs decision.

Do you mean the MISC_FMT_CREDENTIALS case? That looks intentional to me, as noted in the comment there, and as per Documentation/admin-guide/binfmt-misc.rst's discussion of the credentials flag.