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-rw-r--r--CVE-2017-1000364.mm-fix-new-crash-in-unmapped_area_topdown.patch47
1 files changed, 47 insertions, 0 deletions
diff --git a/CVE-2017-1000364.mm-fix-new-crash-in-unmapped_area_topdown.patch b/CVE-2017-1000364.mm-fix-new-crash-in-unmapped_area_topdown.patch
new file mode 100644
index 00000000000..25fc3f55d6e
--- /dev/null
+++ b/CVE-2017-1000364.mm-fix-new-crash-in-unmapped_area_topdown.patch
@@ -0,0 +1,47 @@
+From f4cb767d76cf7ee72f97dd76f6cfa6c76a5edc89 Mon Sep 17 00:00:00 2001
+From: Hugh Dickins <hughd@google.com>
+Date: Tue, 20 Jun 2017 02:10:44 -0700
+Subject: [PATCH] mm: fix new crash in unmapped_area_topdown()
+
+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().
+
+Cc: stable@vger.kernel.org
+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>
+---
+ mm/mmap.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/mm/mmap.c b/mm/mmap.c
+index 8e07976d5e477..290b77d9a01e0 100644
+--- a/mm/mmap.c
++++ b/mm/mmap.c
+@@ -1817,7 +1817,8 @@ unsigned long unmapped_area(struct vm_unmapped_area_info *info)
+ /* 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 */
+@@ -1920,7 +1921,8 @@ unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
+ 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 */