staging: android: ion: Zero CMA allocated memory

Since commit 204f672255c2 ("staging: android: ion: Use CMA APIs directly")
the CMA API is now used directly and therefore the allocated memory is no
longer automatically zeroed.

Explicitly zero CMA allocated memory to ensure that no data is exposed to
userspace.

Fixes: 204f672255c2 ("staging: android: ion: Use CMA APIs directly")
Signed-off-by: Liam Mark <lmark@codeaurora.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/android/ion/ion_cma_heap.c b/drivers/staging/android/ion/ion_cma_heap.c
index 94e06925c712b5e52bb06d240ee33057077f8b0a..49718c96bf9ee3de6734ec9acfde9aa8fbc738d8 100644 (file)
--- a/drivers/staging/android/ion/ion_cma_heap.c
+++ b/drivers/staging/android/ion/ion_cma_heap.c
@@ -12,6 +12,7 @@
 #include <linux/err.h>
 #include <linux/cma.h>
 #include <linux/scatterlist.h>
+#include <linux/highmem.h>
 
 #include "ion.h"
 
@@ -42,6 +43,22 @@ static int ion_cma_allocate(struct ion_heap *heap, struct ion_buffer *buffer,
        if (!pages)
                return -ENOMEM;
 
+       if (PageHighMem(pages)) {
+               unsigned long nr_clear_pages = nr_pages;
+               struct page *page = pages;
+
+               while (nr_clear_pages > 0) {
+                       void *vaddr = kmap_atomic(page);
+
+                       memset(vaddr, 0, PAGE_SIZE);
+                       kunmap_atomic(vaddr);
+                       page++;
+                       nr_clear_pages--;
+               }
+       } else {
+               memset(page_address(pages), 0, size);
+       }
+
        table = kmalloc(sizeof(*table), GFP_KERNEL);
        if (!table)
                goto err;