diff --git a/block/ioctl.c b/block/ioctl.c
index 61feed686418..98c4c7b9e7fe 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -18,6 +18,8 @@
 #include "blk.h"
 #include "blk-crypto-internal.h"
 
+#define PR_KEYS_MAX_NUM		(1u << 16)
+
 static int blkpg_do_ioctl(struct block_device *bdev,
 			  struct blkpg_partition __user *upart, int op)
 {
@@ -442,11 +444,12 @@ static int blkdev_pr_read_keys(struct block_device *bdev, blk_mode_t mode,
 	if (copy_from_user(&read_keys, arg, sizeof(read_keys)))
 		return -EFAULT;
 
-	keys_info_len = struct_size(keys_info, keys, read_keys.num_keys);
-	if (keys_info_len == SIZE_MAX)
+	if (read_keys.num_keys > PR_KEYS_MAX_NUM)
 		return -EINVAL;
 
-	keys_info = kzalloc(keys_info_len, GFP_KERNEL);
+	keys_info_len = struct_size(keys_info, keys, read_keys.num_keys);
+
+	keys_info = kvzalloc(keys_info_len, GFP_KERNEL);
 	if (!keys_info)
 		return -ENOMEM;
 
@@ -473,7 +476,7 @@ static int blkdev_pr_read_keys(struct block_device *bdev, blk_mode_t mode,
 	if (copy_to_user(arg, &read_keys, sizeof(read_keys)))
 		ret = -EFAULT;
 out:
-	kfree(keys_info);
+	kvfree(keys_info);
 	return ret;
 }