linux-kernel - [PATCH v3] staging: android: ion: Zero CMA allocated memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 26 Jan 2018 09:48:18 -0800 (PST)
From:   Liam Mark <lmark@...eaurora.org>
To:     Laura Abbott <labbott@...hat.com>,
        Sumit Semwal <sumit.semwal@...aro.org>
cc:     Dan Carpenter <dan.carpenter@...cle.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org,
        linaro-mm-sig@...ts.linaro.org
Subject: [PATCH v3] 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@...eaurora.org>
---
Changes in v2:
  - Clean up the commit message.
  - Add 'Fixes:'

Changes in v3:
 - Add support for highmem pages

 drivers/staging/android/ion/ion_cma_heap.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/staging/android/ion/ion_cma_heap.c b/drivers/staging/android/ion/ion_cma_heap.c
index 86196ffd2faf..fa3e4b7e0c9f 100644
--- a/drivers/staging/android/ion/ion_cma_heap.c
+++ b/drivers/staging/android/ion/ion_cma_heap.c
@@ -21,6 +21,7 @@
 #include <linux/err.h>
 #include <linux/cma.h>
 #include <linux/scatterlist.h>
+#include <linux/highmem.h>
 
 #include "ion.h"
 
@@ -51,6 +52,22 @@ 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;
-- 
1.8.5.2


Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project