[PATCH 3.14 62/83] mtd: sm_ftl: heap corruption in sm_create_sysfs_attributes()

Greg Kroah-Hartman
2014-05-11T19:24:52Z

From: Dan Carpenter <dan.carpenter@oracle.com>

commit b4c233057771581698a13694ab6f33b48ce837dc upstream.

We always put a NUL terminator one space past the end of the "vendor"
buffer. Walter Harms also pointed out that this should just use
kstrndup().

Fixes: 7d17c02a01a1 ('mtd: Add new SmartMedia/xD FTL')

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/mtd/sm_ftl.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

--- a/drivers/mtd/sm_ftl.c
+++ b/drivers/mtd/sm_ftl.c
@@ -59,15 +59,12 @@ static struct attribute_group *sm_create
struct attribute_group *attr_group;
struct attribute **attributes;
struct sm_sysfs_attribute *vendor_attribute;
+ char *vendor;

- int vendor_len = strnlen(ftl->cis_buffer + SM_CIS_VENDOR_OFFSET,
- SM_SMALL_PAGE - SM_CIS_VENDOR_OFFSET);
-
- char *vendor = kmalloc(vendor_len, GFP_KERNEL);
+ vendor = kstrndup(ftl->cis_buffer + SM_CIS_VENDOR_OFFSET,
+ SM_SMALL_PAGE - SM_CIS_VENDOR_OFFSET, GFP_KERNEL);
if (!vendor)
goto error1;
- memcpy(vendor, ftl->cis_buffer + SM_CIS_VENDOR_OFFSET, vendor_len);
- vendor[vendor_len] = 0;

/* Initialize sysfs attributes */
vendor_attribute =
@@ -78,7 +75,7 @@ static struct attribute_group *sm_create
sysfs_attr_init(&vendor_attribute->dev_attr.attr);

vendor_attribute->data = vendor;
- vendor_attribute->len = vendor_len;
+ vendor_attribute->len = strlen(vendor);
vendor_attribute->dev_attr.attr.name = "vendor";
vendor_attribute->dev_attr.attr.mode = S_IRUGO;
vendor_attribute->dev_attr.show = sm_attr_show;