dm: limit the number of targets and parameter size area

commit bd504bcfec41a503b32054da5472904b404341a4 upstream.

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.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: He Gao <hegao@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index 3db92d9a030b9051e1337661b017a719ac998293..ff73b2c17be538a48dbe267424d3e72e404f8ae4 100644 (file)
--- 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 5f9b9178c647e2e64632b78c70c3538ef1513f8e..4184c8a2d49771cf95b2ed9b25650d5842d65a9e 100644 (file)
--- 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 5c590895c14c37b68fbd544ac7c92402f6a43d45..31bcdcd93c7a873e4cfaad7fe488d8537a404c39 100644 (file)
--- 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)) {