[PATCH 3.11 184/198] target: Explicitly clear ramdisk_mcp backend pages
From: Luis Henriques
Date: Thu Jul 03 2014 - 05:29:07 EST
3.11.10.13 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
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.
[ 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 is a one-liner that addresses the bug for all <= v3.14 versions. ]
Reported-by: Jorge Daniel Sequeira Matias <jdsm@xxxxxxxxxxxxxxxxxx>
Cc: Jorge Daniel Sequeira Matias <jdsm@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/target/target_core_rd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index 51127d15d5c5..d71cdbed413b 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -179,7 +179,7 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
- 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");
--
1.9.1
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