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>
[srish: Apply to stable branch linux-5.4.y]
Signed-off-by: Srish Srinivasan <srish.srinivasan@broadcom.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 3fea121fcbcf933aa2cbea9c7d4ec4444910dbde..e3c3bbe92677c499a1b99f412d584547b80ab886 100644 (file)
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -18,6 +18,8 @@
 #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 8e787677a8104414864f130ecbef7ddc5f00d816..e89e710dd29205996c678e263906680aa8a998c5 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 8b05d938aa98953c7046a2788123e165043bf71f..fcb9e2775f78a11140463a66d986f29186744fbc 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -184,7 +184,12 @@ 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;
@@ -199,7 +204,7 @@ 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)) {