msm: kgsl: Remove VM_MAYWRITE flag to restrict mprotect
When VM_MAYWRITE flag is used during mmap(), mprotect()
can be used later to change the protection of memstore
to allow write. Make sure this does not happen by
removing VM_MAYWRITE from the vm_flags of vma.
Change-Id: I6f69f05858ea40611d512cfa796caabeaa88cdb5
Signed-off-by: Indira Biruduraju <ibirudur@codeaurora.org>
diff --git a/drivers/gpu/msm/kgsl.c b/drivers/gpu/msm/kgsl.c
index b47f095..2ddf48a 100644
--- a/drivers/gpu/msm/kgsl.c
+++ b/drivers/gpu/msm/kgsl.c
@@ -4139,6 +4139,8 @@
if (vma->vm_flags & VM_WRITE)
return -EPERM;
+ vma->vm_flags &= ~VM_MAYWRITE;
+
if (memdesc->size != vma_size) {
KGSL_MEM_ERR(device, "memstore bad size: %d should be %llu\n",
vma_size, memdesc->size);