[apparmor] [PATCH v2] Allow access to sys devices nodes for libnuma

[Hector Cao]

Hi John,
Agree, let me send another patch, this one can be considered obsolete

On Mon, Feb 24, 2025 at 10:02 AM John Johansen <john.johansen at canonical.com>
wrote:

> On 2/13/25 07:57, Hector Cao wrote:
> > For executables dynamically linked to libnuma, the runtimer linker
> > invokes libnuma functions (num_init) that try to access
> > /sys/devices/system/node/ and if the application's apparmor
> > profile does not allow this access, this access will be denied
> > by apparmor with following error message:
> >
> >    apparmor="DENIED" operation="open" class="file"
> >    name="/sys/devices/system/node/" comm="qemu-bridge-hel"
> >    requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
> >
> > Here is the simplified call trace:
> >
> >    0 ... in ?? () from /lib/x86_64-linux-gnu/libnuma.so.1
> >    1 ... in call_init (...) at ./elf/dl-init.c:74
> >    2 ... in call_init (...) at ./elf/dl-init.c:120
> >    3 _dl_init (...) at ./elf/dl-init.c:121
> >    4 ... in _dl_start_user () from /lib64/ld-linux-x86-64.so.2
> >
> > Allow access to this sysfs folder so that we do not have to
> > specify this permission for every executable linked to libnuma
> >
> what is the advantage of not specifying it? abstractions/base
> violates POLA and needs to go away. So I am very reluctant to
> add anything to base.
>
> Instead of adding the rule to every application linking to
> libnuma we should probably have a numa abstraction. While it
> would have 1 rule atm. As we deconstruct base it will pick up
> a few other rules.
>
>
> > Changes in v2:
> >    - Fix typo: add missing ending '/' character to the path
> >
> > Signed-off-by: Hector Cao <hector.cao at canonical.com>
> > ---
> >   profiles/apparmor.d/abstractions/base | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/profiles/apparmor.d/abstractions/base
> b/profiles/apparmor.d/abstractions/base
> > index bf3f3184e..52cbab920 100644
> > --- a/profiles/apparmor.d/abstractions/base
> > +++ b/profiles/apparmor.d/abstractions/base
> > @@ -108,6 +108,8 @@
> >     @{sys}/devices/system/cpu/       r,
> >     @{sys}/devices/system/cpu/online r,
> >     @{sys}/devices/system/cpu/possible r,
> > +  # runtime initialization for binaries linked to libnuma
> > +  @{sys}/devices/system/node/     r,
> >
> >     # transparent hugepage support
> >     @{sys}/kernel/mm/transparent_hugepage/hpage_pmd_size r,
>
>
>

-- 
Hector CAO
Software Engineer – Partner Engineering Team
hector.cao at canonical.com
https://launc <https://launchpad.net/~hectorcao>hpad.net/~hectorcao
<https://launchpad.net/~hectorcao>

<https://launchpad.net/~hectorcao>
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