[PATCH 08/10] mm: Prevent mremap of shadow stack

[Yu-cheng Yu]

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
---
 mm/mremap.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 049470aa1e3e..70f20edb248e 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -525,7 +525,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 		unsigned long, new_addr)
 {
 	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma = find_vma(mm, addr);
 	unsigned long ret = -EINVAL;
 	unsigned long charged = 0;
 	bool locked = false;
@@ -533,6 +533,9 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 	LIST_HEAD(uf_unmap_early);
 	LIST_HEAD(uf_unmap);
 
+	if (vma->vm_flags & VM_SHSTK)
+		return ret;
+
 	if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
 		return ret;
 
-- 
2.15.1