Backport fix for CVE-2017-1000364 to linux-yocto-4.4

Backport of upstream fixes from 4.4 kernel branch to linux-yocto:
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/?h=linux-4.4.y&id=4b359430674caa2c98d0049a6941f157d2a33741
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/?h=linux-4.4.y&id=f41512c6acb71c63cf4e3bd50934365ae2a23891
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/?h=linux-4.4.y&id=1f2284fac2180d7a9442c796d9755e3ce7ab0bd9

Bug-AGL: SPEC-705 SPEC-706

Change-Id: I8f180d6d58d985ca7186638015a57d3d836a9a61
Signed-off-by: Jan-Simon Möller <jsmoeller@linuxfoundation.org>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/9861
Tested-by: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-build: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-boot-test: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
Reviewed-by: Stéphane Desneux <stephane.desneux@iot.bzh>

1 files changed, 52 insertions, 0 deletions

diff --git a/meta-agl-bsp/recipes-kernel/linux/linux-yocto/0003-mm-fix-new-crash-in-unmapped_area_topdown.patch b/meta-agl-bsp/recipes-kernel/linux/linux-yocto/0003-mm-fix-new-crash-in-unmapped_area_topdown.patch
new file mode 100644
index 000000000..f8865d8bc
--- /dev/null
+++ b/meta-agl-bsp/recipes-kernel/linux/linux-yocto/0003-mm-fix-new-crash-in-unmapped_area_topdown.patch
@@ -0,0 +1,52 @@
+From ec63c36f85e7ca803e8c303f5c4a802a3ae45dec Mon Sep 17 00:00:00 2001
+From: Hugh Dickins <hughd@google.com>
+Date: Tue, 20 Jun 2017 02:10:44 -0700
+Subject: [PATCH 3/3] mm: fix new crash in unmapped_area_topdown()
+
+commit f4cb767d76cf7ee72f97dd76f6cfa6c76a5edc89 upstream.
+
+Trinity gets kernel BUG at mm/mmap.c:1963! in about 3 minutes of
+mmap testing.  That's the VM_BUG_ON(gap_end < gap_start) at the
+end of unmapped_area_topdown().  Linus points out how MAP_FIXED
+(which does not have to respect our stack guard gap intentions)
+could result in gap_end below gap_start there.  Fix that, and
+the similar case in its alternative, unmapped_area().
+
+Fixes: 1be7107fbe18 ("mm: larger stack guard gap, between vmas")
+Reported-by: Dave Jones <davej@codemonkey.org.uk>
+Debugged-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Hugh Dickins <hughd@google.com>
+Acked-by: Michal Hocko <mhocko@suse.com>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/mmap.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/mm/mmap.c b/mm/mmap.c
+index 3ca4fc9f0dac..35da0ff7d737 100644
+--- a/mm/mmap.c
++++ b/mm/mmap.c
+@@ -1771,7 +1771,8 @@ check_current:
+ 		/* Check if current node has a suitable gap */
+ 		if (gap_start > high_limit)
+ 			return -ENOMEM;
+-		if (gap_end >= low_limit && gap_end - gap_start >= length)
++		if (gap_end >= low_limit &&
++		    gap_end > gap_start && gap_end - gap_start >= length)
+ 			goto found;
+ 
+ 		/* Visit right subtree if it looks promising */
+@@ -1874,7 +1875,8 @@ check_current:
+ 		gap_end = vm_start_gap(vma);
+ 		if (gap_end < low_limit)
+ 			return -ENOMEM;
+-		if (gap_start <= high_limit && gap_end - gap_start >= length)
++		if (gap_start <= high_limit &&
++		    gap_end > gap_start && gap_end - gap_start >= length)
+ 			goto found;
+ 
+ 		/* Visit left subtree if it looks promising */
+-- 
+2.12.3
+