Access to the files in /sys/firmware/efi/esrt has been restricted to
CAP_SYS_ADMIN since support for ESRT was added, but this seems overly
restrictive given that the files are read-only and just provide
information about UEFI firmware updates.
Remove the CAP_SYS_ADMIN restriction so that a non-root process can read
the files, provided a suitably-privileged process changes the file
ownership first. The files are still read-only and still owned by root by
default.
Signed-off-by: Nicholas Bishop <[email protected]>
---
drivers/firmware/efi/esrt.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/firmware/efi/esrt.c b/drivers/firmware/efi/esrt.c
index d5915272141f..aab96ab64a1a 100644
--- a/drivers/firmware/efi/esrt.c
+++ b/drivers/firmware/efi/esrt.c
@@ -95,10 +95,6 @@ static ssize_t esre_attr_show(struct kobject *kobj,
struct esre_entry *entry = to_entry(kobj);
struct esre_attribute *attr = to_attr(_attr);
- /* Don't tell normal users what firmware versions we've got... */
- if (!capable(CAP_SYS_ADMIN))
- return -EACCES;
-
return attr->show(entry, buf);
}
--
2.40.1.606.ga4b1b128d6-goog
On Fri, 12 May 2023 at 21:43, Nicholas Bishop <[email protected]> wrote:
>
> Access to the files in /sys/firmware/efi/esrt has been restricted to
> CAP_SYS_ADMIN since support for ESRT was added, but this seems overly
> restrictive given that the files are read-only and just provide
> information about UEFI firmware updates.
>
> Remove the CAP_SYS_ADMIN restriction so that a non-root process can read
> the files, provided a suitably-privileged process changes the file
> ownership first. The files are still read-only and still owned by root by
> default.
>
> Signed-off-by: Nicholas Bishop <[email protected]>
Seems reasonable to me. Peter?
> ---
> drivers/firmware/efi/esrt.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/drivers/firmware/efi/esrt.c b/drivers/firmware/efi/esrt.c
> index d5915272141f..aab96ab64a1a 100644
> --- a/drivers/firmware/efi/esrt.c
> +++ b/drivers/firmware/efi/esrt.c
> @@ -95,10 +95,6 @@ static ssize_t esre_attr_show(struct kobject *kobj,
> struct esre_entry *entry = to_entry(kobj);
> struct esre_attribute *attr = to_attr(_attr);
>
> - /* Don't tell normal users what firmware versions we've got... */
> - if (!capable(CAP_SYS_ADMIN))
> - return -EACCES;
> -
> return attr->show(entry, buf);
> }
>
> --
> 2.40.1.606.ga4b1b128d6-goog
>
On Mon, 22 May 2023 at 10:11, Ard Biesheuvel <[email protected]> wrote:
>
> On Fri, 12 May 2023 at 21:43, Nicholas Bishop <[email protected]> wrote:
> >
> > Access to the files in /sys/firmware/efi/esrt has been restricted to
> > CAP_SYS_ADMIN since support for ESRT was added, but this seems overly
> > restrictive given that the files are read-only and just provide
> > information about UEFI firmware updates.
> >
> > Remove the CAP_SYS_ADMIN restriction so that a non-root process can read
> > the files, provided a suitably-privileged process changes the file
> > ownership first. The files are still read-only and still owned by root by
> > default.
> >
> > Signed-off-by: Nicholas Bishop <[email protected]>
>
> Seems reasonable to me. Peter?
>
I've queued this up now.
> > ---
> > drivers/firmware/efi/esrt.c | 4 ----
> > 1 file changed, 4 deletions(-)
> >
> > diff --git a/drivers/firmware/efi/esrt.c b/drivers/firmware/efi/esrt.c
> > index d5915272141f..aab96ab64a1a 100644
> > --- a/drivers/firmware/efi/esrt.c
> > +++ b/drivers/firmware/efi/esrt.c
> > @@ -95,10 +95,6 @@ static ssize_t esre_attr_show(struct kobject *kobj,
> > struct esre_entry *entry = to_entry(kobj);
> > struct esre_attribute *attr = to_attr(_attr);
> >
> > - /* Don't tell normal users what firmware versions we've got... */
> > - if (!capable(CAP_SYS_ADMIN))
> > - return -EACCES;
> > -
> > return attr->show(entry, buf);
> > }
> >
> > --
> > 2.40.1.606.ga4b1b128d6-goog
> >
On Mon, May 22, 2023 at 4:11 AM Ard Biesheuvel <[email protected]> wrote:
>
> On Fri, 12 May 2023 at 21:43, Nicholas Bishop <[email protected]> wrote:
> >
> > Access to the files in /sys/firmware/efi/esrt has been restricted to
> > CAP_SYS_ADMIN since support for ESRT was added, but this seems overly
> > restrictive given that the files are read-only and just provide
> > information about UEFI firmware updates.
> >
> > Remove the CAP_SYS_ADMIN restriction so that a non-root process can read
> > the files, provided a suitably-privileged process changes the file
> > ownership first. The files are still read-only and still owned by root by
> > default.
> >
> > Signed-off-by: Nicholas Bishop <[email protected]>
>
> Seems reasonable to me. Peter?
Yeah, I don't think we had any specific reason to limit it.
-- Peter