Re: [PATCH 1/2] audit: remove redundant data_len check
On Sun, May 15, 2022 at 7:35 PM Paul Moore wrote: > > On Sun, May 15, 2022 at 3:31 AM Shreenidhi Shedi wrote: > > > > data_len is already getting checked if it's less than 2 earlier in this > > function. > > > > Signed-off-by: Shreenidhi Shedi > > --- > > kernel/audit.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > Thanks, this patch looks okay, but since we are already at v5.18-rc7 > this patch will have to wait until after the upcoming merge window as > it isn't a critical bug fix. ... and it's now merged into audit/next, thanks! -- paul-moore.com -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit
Re: Be careful with rules
On 6/7/22 09:14, Paul Moore wrote: On Tue, Jun 7, 2022 at 11:02 AM Steve Grubb wrote: On Tuesday, June 7, 2022 9:42:06 AM EDT Paul Moore wrote: On Mon, Jun 6, 2022 at 7:10 PM Lenny Bruzenak wrote: I've been told that it is not a potential security problem, and not subject to change in the (current) kernel. I'm that little birdy that Lenny was talking to off-list so I figured I would add a quick comment here :) As a reminder, elevated privilege is needed to both add/remove/modify audit rules as well as the loaded SELinux policy (affecting the validity of the relevant security labels). Also, as Lenny already mentioned, if an invalid security label is used, the kernel will notify the admin via the kernel log. Wouldn't it be better if the kernel knew the rule was invalid to return EINVAL so that rule loading stops or becomes an error return from auditctl? A long time ago, there was no way from user space to check a type or a role or an selinux user for validity. Can that be done now? Is there an API for it? We don't want to change how the kernel responds to userspace input unless we have no (good) choice. According to the git log, the kernel has behaved like this for almost 20 years, this is not something we want to change, especially given that we already need to trust the administrator to configure the system correctly. As I told Lenny earlier, I agree that the existing behavior is a bit silly, but it's not something we can really change at this point with the current API. Future API changes will make things like this much easier (hopefully I'll have more to share on this later this year). For anyone who has audit rules that include type filters for subject or object (subj_user, subj_role, subj_type, subj_sen, subj_clr, obj_ser, obj_role, obj_type, obj_lev_low, or obj_lev_high), I recommend doing this ASAP to see if you are affected: # dmesg | grep "LSM.*invalid" If you see this, you are affected. No OpenSCAP scans or other userspace security validators will catch this AFAIK. LCB -- Lenny Bruzenak MagitekLTD -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit
Re: Be careful with rules
On Tue, Jun 7, 2022 at 11:02 AM Steve Grubb wrote: > On Tuesday, June 7, 2022 9:42:06 AM EDT Paul Moore wrote: > > On Mon, Jun 6, 2022 at 7:10 PM Lenny Bruzenak wrote: > > > I've been told that it is not a potential security problem, and not > > > subject to change in the (current) kernel. > > > > I'm that little birdy that Lenny was talking to off-list so I figured > > I would add a quick comment here :) > > > > As a reminder, elevated privilege is needed to both add/remove/modify > > audit rules as well as the loaded SELinux policy (affecting the > > validity of the relevant security labels). Also, as Lenny already > > mentioned, if an invalid security label is used, the kernel will > > notify the admin via the kernel log. > > Wouldn't it be better if the kernel knew the rule was invalid to return > EINVAL so that rule loading stops or becomes an error return from auditctl? A > long time ago, there was no way from user space to check a type or a role or > an selinux user for validity. Can that be done now? Is there an API for it? We don't want to change how the kernel responds to userspace input unless we have no (good) choice. According to the git log, the kernel has behaved like this for almost 20 years, this is not something we want to change, especially given that we already need to trust the administrator to configure the system correctly. As I told Lenny earlier, I agree that the existing behavior is a bit silly, but it's not something we can really change at this point with the current API. Future API changes will make things like this much easier (hopefully I'll have more to share on this later this year). -- paul-moore.com -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit
Re: Be careful with rules
Hello Paul, On Tuesday, June 7, 2022 9:42:06 AM EDT Paul Moore wrote: > On Mon, Jun 6, 2022 at 7:10 PM Lenny Bruzenak wrote: > > I've been told that it is not a potential security problem, and not > > subject to change in the (current) kernel. > > I'm that little birdy that Lenny was talking to off-list so I figured > I would add a quick comment here :) > > As a reminder, elevated privilege is needed to both add/remove/modify > audit rules as well as the loaded SELinux policy (affecting the > validity of the relevant security labels). Also, as Lenny already > mentioned, if an invalid security label is used, the kernel will > notify the admin via the kernel log. Wouldn't it be better if the kernel knew the rule was invalid to return EINVAL so that rule loading stops or becomes an error return from auditctl? A long time ago, there was no way from user space to check a type or a role or an selinux user for validity. Can that be done now? Is there an API for it? -Steve -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit
Re: Be careful with rules
On Mon, Jun 6, 2022 at 7:10 PM Lenny Bruzenak wrote: > I've been told that it is not a potential security problem, and not subject > to change in the (current) kernel. I'm that little birdy that Lenny was talking to off-list so I figured I would add a quick comment here :) As a reminder, elevated privilege is needed to both add/remove/modify audit rules as well as the loaded SELinux policy (affecting the validity of the relevant security labels). Also, as Lenny already mentioned, if an invalid security label is used, the kernel will notify the admin via the kernel log. -- paul-moore.com -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit
