mount.nfs: Protocol error after upgrade to linux/master

[Tetsuo Handa]

On 2019/03/23 7:45, Kees Cook wrote:
> It breaks the backward-compat for the "security=" line. If a system is
> booted with CONFIG_LSM="minors...,apparmor" and "security=selinux",
> neither apparmor nor selinux will be initialized. The logic on
> "security=..." depends on the other LSMs being present in the list.

Really? The logic on "security=..." does not depend on LSM_FLAG_LEGACY_MAJOR
LSMs being present in the CONFIG_LSM= list, for ordered_lsm_parse() does

  (Step 1) Enable LSM_ORDER_FIRST module (i.e. capability).

  (Step 2) Disable LSM_FLAG_LEGACY_MAJOR modules which was not specified
           by "security=" parameter when "security=" parameter was specified.

  (Step 3) Enable modules specified by "lsm=" parameter (or CONFIG_LSM= settings
           if "lsm=" parameter was not specified).

  (Step 4) Enable up to one LSM_FLAG_LEGACY_MAJOR module which was specified
           by "security=" parameter when "security=" parameter was specified.

  (Step 5) Disable all unused modules.

and (Step 4) will compensate for lack of that module in (Step 3).