[PATCH 5.10] dm: limit the number of targets and parameter size area

He Gao
2024-02-20T23:50:22Z

[ Upstream commit bd504bcfec41a503b32054da5472904b404341a4 ]

The kvmalloc function fails with a warning if the size is larger than
INT_MAX. The warning was triggered by a syscall testing robot.

In order to avoid the warning, this commit limits the number of targets to
1048576 and the size of the parameter area to 1073741824.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: He Gao <hegao@google.com>
---
drivers/md/dm-core.h | 2 ++
drivers/md/dm-ioctl.c | 3 ++-
drivers/md/dm-table.c | 9 +++++++--
3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index 3db92d9a030b..ff73b2c17be5 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -19,6 +19,8 @@
#include "dm.h"

#define DM_RESERVED_MAX_IOS 1024
+#define DM_MAX_TARGETS 1048576
+#define DM_MAX_TARGET_PARAMS 1024

struct dm_kobject_holder {
struct kobject kobj;
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 5f9b9178c647..4184c8a2d497 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1760,7 +1760,8 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
if (copy_from_user(param_kernel, user, minimum_data_size))
return -EFAULT;

- if (param_kernel->data_size < minimum_data_size)
+ if (unlikely(param_kernel->data_size < minimum_data_size) ||
+ unlikely(param_kernel->data_size > DM_MAX_TARGETS * DM_MAX_TARGET_PARAMS))
return -EINVAL;

secure_data = param_kernel->flags & DM_SECURE_DATA_FLAG;
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 5c590895c14c..31bcdcd93c7a 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -144,7 +144,12 @@ static int alloc_targets(struct dm_table *t, unsigned int num)
int dm_table_create(struct dm_table **result, fmode_t mode,
unsigned num_targets, struct mapped_device *md)
{
- struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
+ struct dm_table *t;
+
+ if (num_targets > DM_MAX_TARGETS)
+ return -EOVERFLOW;
+
+ t = kzalloc(sizeof(*t), GFP_KERNEL);

if (!t)
return -ENOMEM;
@@ -158,7 +163,7 @@ int dm_table_create(struct dm_table **result, fmode_t mode,

if (!num_targets) {
kfree(t);
- return -ENOMEM;
+ return -EOVERFLOW;
}

if (alloc_targets(t, num_targets)) {
--
2.44.0.rc0.258.g7320e95886-goog