4.9-stable patches

added patches:
	fork-unconditionally-clear-stack-on-fork.patch
	kmemleak-clear-stale-pointers-from-task-stacks.patch

diff --git a/queue-4.9/fork-unconditionally-clear-stack-on-fork.patch b/queue-4.9/fork-unconditionally-clear-stack-on-fork.patch
new file mode 100644 (file)
index 0000000..e868292
--- /dev/null
+++ b/queue-4.9/fork-unconditionally-clear-stack-on-fork.patch
@@ -0,0 +1,102 @@
+From e01e80634ecdde1dd113ac43b3adad21b47f3957 Mon Sep 17 00:00:00 2001
+From: Kees Cook <keescook@chromium.org>
+Date: Fri, 20 Apr 2018 14:55:31 -0700
+Subject: fork: unconditionally clear stack on fork
+
+From: Kees Cook <keescook@chromium.org>
+
+commit e01e80634ecdde1dd113ac43b3adad21b47f3957 upstream.
+
+One of the classes of kernel stack content leaks[1] is exposing the
+contents of prior heap or stack contents when a new process stack is
+allocated.  Normally, those stacks are not zeroed, and the old contents
+remain in place.  In the face of stack content exposure flaws, those
+contents can leak to userspace.
+
+Fixing this will make the kernel no longer vulnerable to these flaws, as
+the stack will be wiped each time a stack is assigned to a new process.
+There's not a meaningful change in runtime performance; it almost looks
+like it provides a benefit.
+
+Performing back-to-back kernel builds before:
+       Run times: 157.86 157.09 158.90 160.94 160.80
+       Mean: 159.12
+       Std Dev: 1.54
+
+and after:
+       Run times: 159.31 157.34 156.71 158.15 160.81
+       Mean: 158.46
+       Std Dev: 1.46
+
+Instead of making this a build or runtime config, Andy Lutomirski
+recommended this just be enabled by default.
+
+[1] A noisy search for many kinds of stack content leaks can be seen here:
+https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=linux+kernel+stack+leak
+
+I did some more with perf and cycle counts on running 100,000 execs of
+/bin/true.
+
+before:
+Cycles: 218858861551 218853036130 214727610969 227656844122 224980542841
+Mean:  221015379122.60
+Std Dev: 4662486552.47
+
+after:
+Cycles: 213868945060 213119275204 211820169456 224426673259 225489986348
+Mean:  217745009865.40
+Std Dev: 5935559279.99
+
+It continues to look like it's faster, though the deviation is rather
+wide, but I'm not sure what I could do that would be less noisy.  I'm
+open to ideas!
+
+Link: http://lkml.kernel.org/r/20180221021659.GA37073@beast
+Signed-off-by: Kees Cook <keescook@chromium.org>
+Acked-by: Michal Hocko <mhocko@suse.com>
+Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
+Cc: Andy Lutomirski <luto@kernel.org>
+Cc: Laura Abbott <labbott@redhat.com>
+Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
+Cc: Mel Gorman <mgorman@techsingularity.net>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+[ Srivatsa: Backported to 4.9.y ]
+Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
+Reviewed-by: Srinidhi Rao <srinidhir@vmware.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/linux/thread_info.h |    7 +------
+ kernel/fork.c               |    3 +--
+ 2 files changed, 2 insertions(+), 8 deletions(-)
+
+--- a/include/linux/thread_info.h
++++ b/include/linux/thread_info.h
+@@ -59,12 +59,7 @@ extern long do_no_restart_syscall(struct
+ 
+ #ifdef __KERNEL__
+ 
+-#if IS_ENABLED(CONFIG_DEBUG_STACK_USAGE) || IS_ENABLED(CONFIG_DEBUG_KMEMLEAK)
+-# define THREADINFO_GFP               (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | \
+-                               __GFP_ZERO)
+-#else
+-# define THREADINFO_GFP               (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK)
+-#endif
++#define THREADINFO_GFP        (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | __GFP_ZERO)
+ 
+ /*
+  * flag set/clear/test wrappers
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -184,10 +184,9 @@ static unsigned long *alloc_thread_stack
+                       continue;
+               this_cpu_write(cached_stacks[i], NULL);
+ 
+-#ifdef CONFIG_DEBUG_KMEMLEAK
+               /* Clear stale pointers from reused stack. */
+               memset(s->addr, 0, THREAD_SIZE);
+-#endif
++
+               tsk->stack_vm_area = s;
+               local_irq_enable();
+               return s->addr;

diff --git a/queue-4.9/kmemleak-clear-stale-pointers-from-task-stacks.patch b/queue-4.9/kmemleak-clear-stale-pointers-from-task-stacks.patch
new file mode 100644 (file)
index 0000000..4ee67bb
--- /dev/null
+++ b/queue-4.9/kmemleak-clear-stale-pointers-from-task-stacks.patch
@@ -0,0 +1,49 @@
+From ca182551857cc2c1e6a2b7f1e72090a137a15008 Mon Sep 17 00:00:00 2001
+From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
+Date: Fri, 13 Oct 2017 15:58:22 -0700
+Subject: kmemleak: clear stale pointers from task stacks
+
+From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
+
+commit ca182551857cc2c1e6a2b7f1e72090a137a15008 upstream.
+
+Kmemleak considers any pointers on task stacks as references.  This
+patch clears newly allocated and reused vmap stacks.
+
+Link: http://lkml.kernel.org/r/150728990124.744199.8403409836394318684.stgit@buzz
+Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
+Acked-by: Catalin Marinas <catalin.marinas@arm.com>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+[ Srivatsa: Backported to 4.9.y ]
+Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/linux/thread_info.h |    2 +-
+ kernel/fork.c               |    4 ++++
+ 2 files changed, 5 insertions(+), 1 deletion(-)
+
+--- a/include/linux/thread_info.h
++++ b/include/linux/thread_info.h
+@@ -59,7 +59,7 @@ extern long do_no_restart_syscall(struct
+ 
+ #ifdef __KERNEL__
+ 
+-#ifdef CONFIG_DEBUG_STACK_USAGE
++#if IS_ENABLED(CONFIG_DEBUG_STACK_USAGE) || IS_ENABLED(CONFIG_DEBUG_KMEMLEAK)
+ # define THREADINFO_GFP               (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | \
+                                __GFP_ZERO)
+ #else
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -184,6 +184,10 @@ static unsigned long *alloc_thread_stack
+                       continue;
+               this_cpu_write(cached_stacks[i], NULL);
+ 
++#ifdef CONFIG_DEBUG_KMEMLEAK
++              /* Clear stale pointers from reused stack. */
++              memset(s->addr, 0, THREAD_SIZE);
++#endif
+               tsk->stack_vm_area = s;
+               local_irq_enable();
+               return s->addr;

diff --git a/queue-4.9/series b/queue-4.9/series
index 01f1300fa0a554f71f0e1dd56277d19073aa89ad..53b1054f4e20318c61e1bdbefbde78f777fa573c 100644 (file)
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -11,3 +11,5 @@ ring_buffer-tracing-inherit-the-tracing-setting-to-next-ring-buffer.patch
 i2c-imx-fix-reinit_completion-use.patch
 btrfs-fix-file-data-corruption-after-cloning-a-range-and-fsync.patch
 tcp-add-tcp_ooo_try_coalesce-helper.patch
+kmemleak-clear-stale-pointers-from-task-stacks.patch
+fork-unconditionally-clear-stack-on-fork.patch