binder: validate alloc->mm in ->mmap() handler

[platform/kernel/linux-rpi.git] / drivers / android / binder_alloc.c

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 8ed4501..6acfb89 100644 (file)
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -753,6 +753,12 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
        const char *failure_string;
        struct binder_buffer *buffer;
 
+       if (unlikely(vma->vm_mm != alloc->vma_vm_mm)) {
+               ret = -EINVAL;
+               failure_string = "invalid vma->vm_mm";
+               goto err_invalid_mm;
+       }
+
        mutex_lock(&binder_alloc_mmap_lock);
        if (alloc->buffer_size) {
                ret = -EBUSY;
@@ -799,6 +805,7 @@ err_alloc_pages_failed:
        alloc->buffer_size = 0;
 err_already_mapped:
        mutex_unlock(&binder_alloc_mmap_lock);
+err_invalid_mm:
        binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
                           "%s: %d %lx-%lx %s failed %d\n", __func__,
                           alloc->pid, vma->vm_start, vma->vm_end,