>From dcca9cecaa77cf362e694031de080540f55d6daf Mon Sep 17 00:00:00 2001
From: Hyeonjun Ahn <guswns0863@xxxxxxxxx>
Date: Thu, 9 Nov 2023 11:41:02 +0900
Subject: [PATCH] nbd: limit the number of connections per config
Add max_connections to prevent out-of-memory in nbd_add_socket.
Signed-off-by: Hyeonjun Ahn <guswns0863@xxxxxxxxx>
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: Jens Axboe <axboe@xxxxxxxxx>
---
drivers/block/nbd.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 800f131222fc..69f7fe0d07d6 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -162,6 +162,7 @@ static struct dentry *nbd_dbg_dir;
static unsigned int nbds_max = 16;
static int max_part = 16;
static int part_shift;
+static unsigned long max_connections = PAGE_SIZE / sizeof(struct nbd_sock *);
static int nbd_dev_dbg_init(struct nbd_device *nbd);
static void nbd_dev_dbg_close(struct nbd_device *nbd);
@@ -1117,6 +1118,13 @@ static int nbd_add_socket(struct nbd_device
*nbd, unsigned long arg,
/* Arg will be cast to int, check it to avoid overflow */
if (arg > INT_MAX)
return -EINVAL;
+
+ if (config->num_connections >= max_connections) {
+ dev_err(disk_to_dev(nbd->disk),
+ "Number of socket connections exceeded limit.\n");
+ return -ENOMEM;
+ }
+
sock = nbd_get_socket(nbd, arg, &err);
if (!sock)
return err;
--
2.34.1
2023년 11월 9일 (목) 오전 12:34, Jens Axboe <axboe@xxxxxxxxx>님이 작성:
>
> On 11/7/23 9:30 PM, Hyeonjun Ahn wrote:
> > Thanks for your reviews.
> > Below is the modified patch.
>
> Please send it with a CC to linux-block, as that is the proper list.
> You'll need to ensure it's just plain text, looks like it's html right
> now.
>
> And also add a proper commit message.
>
> --
> Jens Axboe
>
Attachment:
0001-nbd-limit-the-number-of-connections-per-config.patch
Description: Binary data
