Re: Re: [PATCH] net/rds: Fix a use after free in rds_message_map_pages

2021-03-30 Thread lyl2019 



> -原始邮件-
> 发件人: "David Miller" 
> 发送时间: 2021-03-31 08:02:28 (星期三)
> 收件人: lyl2...@mail.ustc.edu.cn
> 抄送: santosh.shilim...@oracle.com, k...@kernel.org, net...@vger.kernel.org, 
> linux-r...@vger.kernel.org, rds-de...@oss.oracle.com, 
> linux-kernel@vger.kernel.org
> 主题: Re: [PATCH] net/rds: Fix a use after free in rds_message_map_pages
> 
> From: Lv Yunlong 
> Date: Tue, 30 Mar 2021 03:16:02 -0700
> 
> > @@ -348,7 +348,7 @@ struct rds_message *rds_message_map_pages(unsigned long 
> > *page_addrs, unsigned in
> > rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
> > if (IS_ERR(rm->data.op_sg)) {
> > rds_message_put(rm);
> > -   return ERR_CAST(rm->data.op_sg);
> > +   return ERR_PTR(-ENOMEM);
> > }
> >  
> > for (i = 0; i < rm->data.op_nents; ++i) {
> 
> Maybe instead do:
> 
>   int err = ERR_CAST(rm->data.op_sg);
>   rds_message_put(rm);
>   return err;
> 
> Then if rds_message_alloc_sgs() starts to return other errors, they will 
> propagate.
> 
> Thank you.

The type of ERR_CAST() is void *, not int. 
I think the correct patch is:

void *err = ERR_CAST(rm->data.op_sg);
rds_message_put(rm);
return err;

I have submitted the PATCH v2 for you to review.

Thanks.

Re: [PATCH] net/rds: Fix a use after free in rds_message_map_pages

2021-03-30 Thread David Miller 
From: Lv Yunlong 
Date: Tue, 30 Mar 2021 03:16:02 -0700

> @@ -348,7 +348,7 @@ struct rds_message *rds_message_map_pages(unsigned long 
> *page_addrs, unsigned in
>   rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
>   if (IS_ERR(rm->data.op_sg)) {
>   rds_message_put(rm);
> - return ERR_CAST(rm->data.op_sg);
> + return ERR_PTR(-ENOMEM);
>   }
>  
>   for (i = 0; i < rm->data.op_nents; ++i) {

Maybe instead do:

  int err = ERR_CAST(rm->data.op_sg);
  rds_message_put(rm);
  return err;

Then if rds_message_alloc_sgs() starts to return other errors, they will 
propagate.

Thank you.

Re: [PATCH] net/rds: Fix a use after free in rds_message_map_pages

2021-03-18 Thread lyl2019 

Just as a reminder,
there has been no reply to this message for more than a week.

Could someone help to fix this issue?

> -原始邮件-
> 发件人: "Lv Yunlong" 
> 发送时间: 2021-03-11 16:46:16 (星期四)
> 收件人: santosh.shilim...@oracle.com, da...@davemloft.net, k...@kernel.org
> 抄送: net...@vger.kernel.org, linux-r...@vger.kernel.org, 
> rds-de...@oss.oracle.com, linux-kernel@vger.kernel.org, "Lv Yunlong" 
> 
> 主题: [PATCH] net/rds: Fix a use after free in rds_message_map_pages
> 
> In rds_message_map_pages, rds_message_put() will free rm.
> Maybe store the value of rm->data.op_sg ahead of rds_message_put()
> is better. Otherwise other threads could allocate the freed chunk
> and may change the value of rm->data.op_sg.
> 
> Signed-off-by: Lv Yunlong 
> ---
>  net/rds/message.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/rds/message.c b/net/rds/message.c
> index 071a261fdaab..392e3a2f41a0 100644
> --- a/net/rds/message.c
> +++ b/net/rds/message.c
> @@ -347,8 +347,9 @@ struct rds_message *rds_message_map_pages(unsigned long 
> *page_addrs, unsigned in
>   rm->data.op_nents = DIV_ROUND_UP(total_len, PAGE_SIZE);
>   rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
>   if (IS_ERR(rm->data.op_sg)) {
> + struct scatterlist *tmp = rm->data.op_sg;
>   rds_message_put(rm);
> - return ERR_CAST(rm->data.op_sg);
> + return ERR_CAST(tmp);
>   }
>  
>   for (i = 0; i < rm->data.op_nents; ++i) {
> -- 
> 2.25.1
>