2022-12-19 09:43:53

by Johan Hovold

Subject: [PATCH] efi: fix NULL-deref in init error path

In case runtime services are not supported or have been disabled the
runtime services workqueue will never have been allocated.

Do not try to destroy the workqueue unconditionally in the unlikely
event that EFI initialisation fails to avoid dereferencing a NULL
pointer.

Fixes: 98086df8b70c ("efi: add missed destroy_workqueue when efisubsys_init fails")
Cc: [email protected]
Cc: Li Heng <[email protected]>
Signed-off-by: Johan Hovold <[email protected]>
---
drivers/firmware/efi/efi.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 09716eebe8ac..a2b0cbc8741c 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -394,8 +394,8 @@ static int __init efisubsys_init(void)
efi_kobj = kobject_create_and_add("efi", firmware_kobj);
if (!efi_kobj) {
pr_err("efi: Firmware registration failed.\n");
- destroy_workqueue(efi_rts_wq);
- return -ENOMEM;
+ error = -ENOMEM;
+ goto err_destroy_wq;
}

if (efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE |
@@ -443,7 +443,10 @@ static int __init efisubsys_init(void)
err_put:
kobject_put(efi_kobj);
efi_kobj = NULL;
- destroy_workqueue(efi_rts_wq);
+err_destroy_wq:
+ if (efi_rts_wq)
+ destroy_workqueue(efi_rts_wq);
+
return error;
}

--
2.37.4

2022-12-23 14:51:20

by Ard Biesheuvel

Subject: Re: [PATCH] efi: fix NULL-deref in init error path

On Mon, 19 Dec 2022 at 10:10, Johan Hovold <[email protected]> wrote:
>
> In case runtime services are not supported or have been disabled the
> runtime services workqueue will never have been allocated.
>
> Do not try to destroy the workqueue unconditionally in the unlikely
> event that EFI initialisation fails to avoid dereferencing a NULL
> pointer.
>
> Fixes: 98086df8b70c ("efi: add missed destroy_workqueue when efisubsys_init fails")
> Cc: [email protected]
> Cc: Li Heng <[email protected]>
> Signed-off-by: Johan Hovold <[email protected]>

Thanks for the fix - I will queue it up after -rc1

> ---
> drivers/firmware/efi/efi.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 09716eebe8ac..a2b0cbc8741c 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -394,8 +394,8 @@ static int __init efisubsys_init(void)
> efi_kobj = kobject_create_and_add("efi", firmware_kobj);
> if (!efi_kobj) {
> pr_err("efi: Firmware registration failed.\n");
> - destroy_workqueue(efi_rts_wq);
> - return -ENOMEM;
> + error = -ENOMEM;
> + goto err_destroy_wq;
> }
>
> if (efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE |
> @@ -443,7 +443,10 @@ static int __init efisubsys_init(void)
> err_put:
> kobject_put(efi_kobj);
> efi_kobj = NULL;
> - destroy_workqueue(efi_rts_wq);
> +err_destroy_wq:
> + if (efi_rts_wq)
> + destroy_workqueue(efi_rts_wq);
> +
> return error;
> }
>
> --
> 2.37.4
>