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Merge branch 'mm-readonly-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull read-only kernel memory updates from Ingo Molnar:
 "This tree adds two (security related) enhancements to the kernel's
  handling of read-only kernel memory:

   - extend read-only kernel memory to a new class of formerly writable
     kernel data: 'post-init read-only memory' via the __ro_after_init
     attribute, and mark the ARM and x86 vDSO as such read-only memory.

     This kind of attribute can be used for data that requires a once
     per bootup initialization sequence, but is otherwise never modified
     after that point.

     This feature was based on the work by PaX Team and Brad Spengler.

     (by Kees Cook, the ARM vDSO bits by David Brown.)

   - make CONFIG_DEBUG_RODATA always enabled on x86 and remove the
     Kconfig option.  This simplifies the kernel and also signals that
     read-only memory is the default model and a first-class citizen.
     (Kees Cook)"

* 'mm-readonly-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ARM/vdso: Mark the vDSO code read-only after init
  x86/vdso: Mark the vDSO code read-only after init
  lkdtm: Verify that '__ro_after_init' works correctly
  arch: Introduce post-init read-only memory
  x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option
  mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings
  asm-generic: Consolidate mark_rodata_ro()
This commit is contained in:
Linus Torvalds
2016-03-14 16:58:50 -07:00
parent 5ec942463b 11bf9b8658
commit d09e356ad0
26 changed files with 103 additions and 84 deletions
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27
init/main.c
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@@ -93,9 +93,6 @@ static int kernel_init(void *);
extern void init_IRQ(void);
extern void fork_init(void);
extern void radix_tree_init(void);
#ifndef CONFIG_DEBUG_RODATA
static inline void mark_rodata_ro(void) { }
#endif
/*
* Debug helper: via this flag we know that we are in 'early bootup code'
@@ -924,6 +921,28 @@ static int try_to_run_init_process(const char *init_filename)
static noinline void __init kernel_init_freeable(void);
#ifdef CONFIG_DEBUG_RODATA
static bool rodata_enabled = true;
static int __init set_debug_rodata(char *str)
{
return strtobool(str, &rodata_enabled);
}
__setup("rodata=", set_debug_rodata);
static void mark_readonly(void)
{
if (rodata_enabled)
mark_rodata_ro();
else
pr_info("Kernel memory protection disabled.\n");
}
#else
static inline void mark_readonly(void)
{
pr_warn("This architecture does not have kernel memory protection.\n");
}
#endif
static int __ref kernel_init(void *unused)
{
int ret;
@@ -932,7 +951,7 @@ static int __ref kernel_init(void *unused)
/* need to finish all async __init code before freeing the memory */
async_synchronize_full();
free_initmem();
mark_rodata_ro();
mark_readonly();
system_state = SYSTEM_RUNNING;
numa_default_policy();