Thread (261 messages) 261 messages, 2 authors, 2014-08-09
STALE4341d

[PATCH 3.13 003/259] target: Explicitly clear ramdisk_mcp backend pages

From: Kamal Mostafa <hidden>
Date: 2014-08-08 22:36:31
Also in: lkml
Subsystem: scsi target subsystem, the rest · Maintainers: "Martin K. Petersen", Linus Torvalds

3.13.11.6 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicholas Bellinger <redacted>

[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 <redacted>
Cc: Jorge Daniel Sequeira Matias <redacted>
Signed-off-by: Nicholas Bellinger <redacted>
Reference: CVE-2014-4027
Signed-off-by: Kamal Mostafa <redacted>
---
 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 4ffe5f2..a97107c 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -178,7 +178,7 @@ 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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