init: move stack canary initialization after setup_arch

Patch series "Command line randomness", v3.

A series to add the kernel command line as a source of randomness.

This patch (of 2):

Stack canary intialization involves getting a random number.  Getting this
random number may involve accessing caches or other architectural specific
features which are not available until after the architecture is setup.
Move the stack canary initialization later to accommodate this.

Link: http://lkml.kernel.org/r/20170816231458.2299-2-labbott@redhat.com
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Nick Kralevich <nnk@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/init/main.c b/init/main.c
index 949306bb5b6ad8e8930ecd11ccac910466674081..ae5d1fd780819ecf8dc3a8a899344e7f0869fcfc 100644 (file)
--- a/init/main.c
+++ b/init/main.c
@@ -515,12 +515,6 @@ asmlinkage __visible void __init start_kernel(void)
        smp_setup_processor_id();
        debug_objects_early_init();
 
-       /*
-        * Set up the initial canary ASAP:
-        */
-       add_latent_entropy();
-       boot_init_stack_canary();
-
        cgroup_init_early();
 
        local_irq_disable();
@@ -534,6 +528,11 @@ asmlinkage __visible void __init start_kernel(void)
        page_address_init();
        pr_notice("%s", linux_banner);
        setup_arch(&command_line);
+       /*
+        * Set up the the initial canary and entropy after arch
+        */
+       add_latent_entropy();
+       boot_init_stack_canary();
        mm_init_cpumask(&init_mm);
        setup_command_line(command_line);
        setup_nr_cpu_ids();