dm: limit the number of targets and parameter size area

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>

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index 095b9b49aa8250a1f56c531883cce5f6e8a24727..e6757a30dccad1fa1a6ae060b33d41a6a120dda3 100644 (file)
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -22,6 +22,8 @@
 #include "dm-ima.h"
 
 #define DM_RESERVED_MAX_IOS            1024
+#define DM_MAX_TARGETS                 1048576
+#define DM_MAX_TARGET_PARAMS           1024
 
 struct dm_io;
 

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index e65058e0ed06ab73b9d20d26dfbf7aca55829572..3b1ad7127cb846a1b50059921241f2abe63eaf53 100644 (file)
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1941,7 +1941,8 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
                           minimum_data_size - sizeof(param_kernel->version)))
                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)) {
                DMERR("Invalid data size in the ioctl structure: %u",
                      param_kernel->data_size);
                return -EINVAL;

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 260b5b8f2b0d7e9352ed9ed9376a91504ee10c9d..41f1d731ae5ac275d90fbc334666438187da02b4 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -129,7 +129,12 @@ static int alloc_targets(struct dm_table *t, unsigned int num)
 int dm_table_create(struct dm_table **result, blk_mode_t mode,
                    unsigned int 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;
@@ -144,7 +149,7 @@ int dm_table_create(struct dm_table **result, blk_mode_t mode,
 
        if (!num_targets) {
                kfree(t);
-               return -ENOMEM;
+               return -EOVERFLOW;
        }
 
        if (alloc_targets(t, num_targets)) {