2022-01-24 19:11:55

by Miaoqian Lin

Subject: [PATCH v2] RDMA/rtrs: Fix double free in alloc_clt

Callback function rtrs_clt_dev_release() in put_device()
calls kfree(clt); to free memory. We shouldn't call kfree(clt) again.

Fixes: 6a98d71daea1 ("RDMA/rtrs: client: main functionality")
Signed-off-by: Miaoqian Lin <[email protected]>
---
Changes in v2:
- call free_percpu() before put_device() to avoid UAF.
---
drivers/infiniband/ulp/rtrs/rtrs-clt.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index 7c3f98e57889..aff04f566304 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -2739,10 +2739,8 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
*/
dev_set_uevent_suppress(&clt->dev, true);
err = device_register(&clt->dev);
- if (err) {
- put_device(&clt->dev);
- goto err;
- }
+ if (err)
+ goto err_register;

clt->kobj_paths = kobject_create_and_add("paths", &clt->dev.kobj);
if (!clt->kobj_paths) {
@@ -2764,6 +2762,11 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
err:
free_percpu(clt->pcpu_path);
kfree(clt);
+ goto ret;
+err_register:
+ free_percpu(clt->pcpu_path);
+ put_device(&clt->dev);
+ret:
return ERR_PTR(err);
}

--
2.17.1

2022-01-25 08:37:17

by Jinpu Wang

Subject: Re: [PATCH v2] RDMA/rtrs: Fix double free in alloc_clt

On Mon, Jan 24, 2022 at 1:21 PM Miaoqian Lin <[email protected]> wrote:
>
> Callback function rtrs_clt_dev_release() in put_device()
> calls kfree(clt); to free memory. We shouldn't call kfree(clt) again.
>
> Fixes: 6a98d71daea1 ("RDMA/rtrs: client: main functionality")
> Signed-off-by: Miaoqian Lin <[email protected]>
Hi Miaoqian,
this is the complete fix.
https://lore.kernel.org/linux-rdma/Ye00cQ+VUkzh8JCH@unreal/T/#t

Thanks!
> ---
> Changes in v2:
> - call free_percpu() before put_device() to avoid UAF.
> ---
> drivers/infiniband/ulp/rtrs/rtrs-clt.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> index 7c3f98e57889..aff04f566304 100644
> --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> @@ -2739,10 +2739,8 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
> */
> dev_set_uevent_suppress(&clt->dev, true);
> err = device_register(&clt->dev);
> - if (err) {
> - put_device(&clt->dev);
> - goto err;
> - }
> + if (err)
> + goto err_register;
>
> clt->kobj_paths = kobject_create_and_add("paths", &clt->dev.kobj);
> if (!clt->kobj_paths) {
> @@ -2764,6 +2762,11 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
> err:
> free_percpu(clt->pcpu_path);
> kfree(clt);
> + goto ret;
> +err_register:
> + free_percpu(clt->pcpu_path);
> + put_device(&clt->dev);
> +ret:
> return ERR_PTR(err);
> }
>
> --
> 2.17.1
>