Fix up backported ptrace patch

[thirdparty/kernel/stable-queue.git] / releases / 3.4.96 / target-explicitly-clear-ramdisk_mcp-backend-pages.patch

From nab@linux-iscsi.org  Fri Jun 27 17:13:41 2014
From: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Date: Mon, 16 Jun 2014 20:59:52 +0000
Subject: [PATCH] target: Explicitly clear ramdisk_mcp backend pages
To: target-devel <target-devel@vger.kernel.org>
Cc: Greg-KH <gregkh@linuxfoundation.org>, stable <stable@vger.kernel.org>, Nicholas Bellinger <nab@linux-iscsi.org>, Jorge Daniel Sequeira Matias <jdsm@tecnico.ulisboa.pt>
Message-ID: <1402952392-30762-1-git-send-email-nab@linux-iscsi.org>


[Note that a different patch to address the same issue went in during
v3.15-rc1 (commit 4442dc8a), but includes a bunch of other changes that
don't strictly apply to fixing the bug]

This patch changes rd_allocate_sgl_table() to explicitly clear
ramdisk_mcp backend memory pages by passing __GFP_ZERO into
alloc_pages().

This addresses a potential security issue where reading from a
ramdisk_mcp could return sensitive information, and follows what
>= v3.15 does to explicitly clear ramdisk_mcp memory at backend
device initialization time.

Reported-by: Jorge Daniel Sequeira Matias <jdsm@tecnico.ulisboa.pt>
Cc: Jorge Daniel Sequeira Matias <jdsm@tecnico.ulisboa.pt>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/target/target_core_rd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -177,7 +177,7 @@ static int rd_build_device_space(struct
 						- 1;
 
 		for (j = 0; j < sg_per_table; j++) {
-			pg = alloc_pages(GFP_KERNEL, 0);
+			pg = alloc_pages(GFP_KERNEL | __GFP_ZERO, 0);
 			if (!pg) {
 				pr_err("Unable to allocate scatterlist"
 					" pages for struct rd_dev_sg_table\n");