[PATCH] selinux: log anon inode class name

[PATCH] selinux: log anon inode class name

[Christian Göttsche]

Log the anonymous inode class name in the security hook
inode_init_security_anon.  This name is the key for name based type
transitions on the anon_inode security class on creation.  Example:

    type=AVC msg=audit(02/16/22 22:02:50.585:216) : avc:  granted  { create } for  pid=2136 comm=mariadbd anonclass="[io_uring]" dev="anon_inodefs" ino=6871 scontext=system_u:system_r:mysqld_t:s0 tcontext=system_u:system_r:mysqld_iouring_t:s0 tclass=anon_inode

Add a new LSM audit data type holding the inode and the class name.

Also warn if the security hook gets called with no name set; currently
the only caller fs/anon_inodes.c:anon_inode_make_secure_inode() passes
one.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
 include/linux/lsm_audit.h |  5 +++++
 security/lsm_audit.c      | 21 +++++++++++++++++++++
 security/selinux/hooks.c  |  7 +++++--
 3 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
index 17d02eda9538..8135a88d6d82 100644
--- a/include/linux/lsm_audit.h
+++ b/include/linux/lsm_audit.h
@@ -76,6 +76,7 @@ struct common_audit_data {
 #define LSM_AUDIT_DATA_IBENDPORT 14
 #define LSM_AUDIT_DATA_LOCKDOWN 15
 #define LSM_AUDIT_DATA_NOTIFICATION 16
+#define LSM_AUDIT_DATA_ANONINODE	17
 	union 	{
 		struct path path;
 		struct dentry *dentry;
@@ -96,6 +97,10 @@ struct common_audit_data {
 		struct lsm_ibpkey_audit *ibpkey;
 		struct lsm_ibendport_audit *ibendport;
 		int reason;
+		struct {
+			struct inode *inode;
+			const char *anonclass;
+		} anoninode_struct;
 	} u;
 	/* this union contains LSM specific data */
 	union {
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 1897cbf6fc69..5545fed35539 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -433,6 +433,27 @@ static void dump_common_audit_data(struct audit_buffer *ab,
 		audit_log_format(ab, " lockdown_reason=\"%s\"",
 				 lockdown_reasons[a->u.reason]);
 		break;
+	case LSM_AUDIT_DATA_ANONINODE: {
+		struct dentry *dentry;
+		struct inode *inode;
+
+		rcu_read_lock();
+		inode = a->u.anoninode_struct.inode;
+		dentry = d_find_alias_rcu(inode);
+		if (dentry) {
+			audit_log_format(ab, " name=");
+			spin_lock(&dentry->d_lock);
+			audit_log_untrustedstring(ab, dentry->d_name.name);
+			spin_unlock(&dentry->d_lock);
+		}
+		audit_log_format(ab, " anonclass=");
+		audit_log_untrustedstring(ab, a->u.anoninode_struct.anonclass);
+		audit_log_format(ab, " dev=");
+		audit_log_untrustedstring(ab, inode->i_sb->s_id);
+		audit_log_format(ab, " ino=%lu", inode->i_ino);
+		rcu_read_unlock();
+		break;
+	}
 	} /* switch (a->type) */
 }
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index dafabb4dcc64..19c831d94d9b 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2932,6 +2932,8 @@ static int selinux_inode_init_security_anon(struct inode *inode,
 	if (unlikely(!selinux_initialized(&selinux_state)))
 		return 0;
 
+	WARN_ON(!name);
+
 	isec = selinux_inode(inode);
 
 	/*
@@ -2965,8 +2967,9 @@ static int selinux_inode_init_security_anon(struct inode *inode,
 	 * allowed to actually create this type of anonymous inode.
 	 */
 
-	ad.type = LSM_AUDIT_DATA_INODE;
-	ad.u.inode = inode;
+	ad.type = LSM_AUDIT_DATA_ANONINODE;
+	ad.u.anoninode_struct.inode = inode;
+	ad.u.anoninode_struct.anonclass = name ? (const char *)name->name : "unknown(null)";
 
 	return avc_has_perm(&selinux_state,
 			    tsec->sid,
-- 
2.35.1

Re: [PATCH] selinux: log anon inode class name

[Paul Moore]

On Thu, Feb 17, 2022 at 9:35 AM Christian Göttsche
<cgzones@googlemail.com> wrote:
>
> Log the anonymous inode class name in the security hook
> inode_init_security_anon.  This name is the key for name based type
> transitions on the anon_inode security class on creation.  Example:
>
>     type=AVC msg=audit(02/16/22 22:02:50.585:216) : avc:  granted  { create } for  pid=2136 comm=mariadbd anonclass="[io_uring]" dev="anon_inodefs" ino=6871 scontext=system_u:system_r:mysqld_t:s0 tcontext=system_u:system_r:mysqld_iouring_t:s0 tclass=anon_inode
>
> Add a new LSM audit data type holding the inode and the class name.
>
> Also warn if the security hook gets called with no name set; currently
> the only caller fs/anon_inodes.c:anon_inode_make_secure_inode() passes
> one.
>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> ---
>  include/linux/lsm_audit.h |  5 +++++
>  security/lsm_audit.c      | 21 +++++++++++++++++++++
>  security/selinux/hooks.c  |  7 +++++--
>  3 files changed, 31 insertions(+), 2 deletions(-)

...

> diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
> index 17d02eda9538..8135a88d6d82 100644
> --- a/include/linux/lsm_audit.h
> +++ b/include/linux/lsm_audit.h
> @@ -76,6 +76,7 @@ struct common_audit_data {
>  #define LSM_AUDIT_DATA_IBENDPORT 14
>  #define LSM_AUDIT_DATA_LOCKDOWN 15
>  #define LSM_AUDIT_DATA_NOTIFICATION 16
> +#define LSM_AUDIT_DATA_ANONINODE       17
>         union   {
>                 struct path path;
>                 struct dentry *dentry;
> @@ -96,6 +97,10 @@ struct common_audit_data {
>                 struct lsm_ibpkey_audit *ibpkey;
>                 struct lsm_ibendport_audit *ibendport;
>                 int reason;
> +               struct {
> +                       struct inode *inode;
> +                       const char *anonclass;
> +               } anoninode_struct;
>         } u;
>         /* this union contains LSM specific data */
>         union {
> diff --git a/security/lsm_audit.c b/security/lsm_audit.c
> index 1897cbf6fc69..5545fed35539 100644
> --- a/security/lsm_audit.c
> +++ b/security/lsm_audit.c
> @@ -433,6 +433,27 @@ static void dump_common_audit_data(struct audit_buffer *ab,
>                 audit_log_format(ab, " lockdown_reason=\"%s\"",
>                                  lockdown_reasons[a->u.reason]);
>                 break;
> +       case LSM_AUDIT_DATA_ANONINODE: {
> +               struct dentry *dentry;
> +               struct inode *inode;
> +
> +               rcu_read_lock();
> +               inode = a->u.anoninode_struct.inode;
> +               dentry = d_find_alias_rcu(inode);
> +               if (dentry) {
> +                       audit_log_format(ab, " name=");
> +                       spin_lock(&dentry->d_lock);
> +                       audit_log_untrustedstring(ab, dentry->d_name.name);
> +                       spin_unlock(&dentry->d_lock);
> +               }

I'm not sure we are ever going to get a useful dentry name for
anonymous inodes, I think we can probably drop this.  The "anonclass="
field will likely be much more interesting and helpful.

> +               audit_log_format(ab, " anonclass=");
> +               audit_log_untrustedstring(ab, a->u.anoninode_struct.anonclass);
> +               audit_log_format(ab, " dev=");
> +               audit_log_untrustedstring(ab, inode->i_sb->s_id);

I'm pretty sure this is always going to end up being "anon_inodefs"
and thus not very useful.

> +               audit_log_format(ab, " ino=%lu", inode->i_ino);

Similarly, I'm not sure how useful the inode number is in practice.
I've never tried, but can a user lookup an anonymous inode via the
inode number?

> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index dafabb4dcc64..19c831d94d9b 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2932,6 +2932,8 @@ static int selinux_inode_init_security_anon(struct inode *inode,
>         if (unlikely(!selinux_initialized(&selinux_state)))
>                 return 0;
>
> +       WARN_ON(!name);
> +
>         isec = selinux_inode(inode);
>
>         /*
> @@ -2965,8 +2967,9 @@ static int selinux_inode_init_security_anon(struct inode *inode,
>          * allowed to actually create this type of anonymous inode.
>          */
>
> -       ad.type = LSM_AUDIT_DATA_INODE;
> -       ad.u.inode = inode;
> +       ad.type = LSM_AUDIT_DATA_ANONINODE;
> +       ad.u.anoninode_struct.inode = inode;
> +       ad.u.anoninode_struct.anonclass = name ? (const char *)name->name : "unknown(null)";

This doesn't seem to match well with the newly added WARN_ON()
assertion above.  I would suggest dropping the WARN_ON() assertion as
security_transition_sid() can already handle that safely, and leaving
the tertiary statement above; however I think we should probably
change the anonclass string to "?" as that is the common unset field
value used by audit.

-- 
paul-moore.com

[PATCH v2] selinux: log anon inode class name

[Christian Göttsche]

Log the anonymous inode class name in the security hook
inode_init_security_anon.  This name is the key for name based type
transitions on the anon_inode security class on creation.  Example:

    type=AVC msg=audit(02/16/22 22:02:50.585:216) : avc:  granted \
        { create } for  pid=2136 comm=mariadbd anonclass="[io_uring]" \
        scontext=system_u:system_r:mysqld_t:s0 \
        tcontext=system_u:system_r:mysqld_iouring_t:s0 tclass=anon_inode

Add a new LSM audit data type holding the inode and the class name.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>

---
v2:
  - drop dev= and name= output for anonymous inodes, and hence simplify
    the common_audit_data union member.
  - drop WARN_ON() on empty name passed to inode_init_security_anon hook
---
 include/linux/lsm_audit.h | 2 ++
 security/lsm_audit.c      | 4 ++++
 security/selinux/hooks.c  | 4 ++--
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
index 17d02eda9538..97a8b21eb033 100644
--- a/include/linux/lsm_audit.h
+++ b/include/linux/lsm_audit.h
@@ -76,6 +76,7 @@ struct common_audit_data {
 #define LSM_AUDIT_DATA_IBENDPORT 14
 #define LSM_AUDIT_DATA_LOCKDOWN 15
 #define LSM_AUDIT_DATA_NOTIFICATION 16
+#define LSM_AUDIT_DATA_ANONINODE	17
 	union 	{
 		struct path path;
 		struct dentry *dentry;
@@ -96,6 +97,7 @@ struct common_audit_data {
 		struct lsm_ibpkey_audit *ibpkey;
 		struct lsm_ibendport_audit *ibendport;
 		int reason;
+		const char *anonclass;
 	} u;
 	/* this union contains LSM specific data */
 	union {
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 1897cbf6fc69..981f6a4e4590 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -433,6 +433,10 @@ static void dump_common_audit_data(struct audit_buffer *ab,
 		audit_log_format(ab, " lockdown_reason=\"%s\"",
 				 lockdown_reasons[a->u.reason]);
 		break;
+	case LSM_AUDIT_DATA_ANONINODE:
+		audit_log_format(ab, " anonclass=");
+		audit_log_untrustedstring(ab, a->u.anonclass);
+		break;
 	} /* switch (a->type) */
 }
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b12e14b2797b..49c0abfd2f6a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2965,8 +2965,8 @@ static int selinux_inode_init_security_anon(struct inode *inode,
 	 * allowed to actually create this type of anonymous inode.
 	 */
 
-	ad.type = LSM_AUDIT_DATA_INODE;
-	ad.u.inode = inode;
+	ad.type = LSM_AUDIT_DATA_ANONINODE;
+	ad.u.anonclass = name ? (const char *)name->name : "?";
 
 	return avc_has_perm(&selinux_state,
 			    tsec->sid,
-- 
2.35.1

Re: [PATCH] selinux: log anon inode class name

[Christian Göttsche]

On Fri, 25 Feb 2022 at 01:25, Paul Moore <paul@paul-moore.com> wrote:
>
> On Thu, Feb 17, 2022 at 9:35 AM Christian Göttsche
> <cgzones@googlemail.com> wrote:
> >
> > Log the anonymous inode class name in the security hook
> > inode_init_security_anon.  This name is the key for name based type
> > transitions on the anon_inode security class on creation.  Example:
> >
> >     type=AVC msg=audit(02/16/22 22:02:50.585:216) : avc:  granted  { create } for  pid=2136 comm=mariadbd anonclass="[io_uring]" dev="anon_inodefs" ino=6871 scontext=system_u:system_r:mysqld_t:s0 tcontext=system_u:system_r:mysqld_iouring_t:s0 tclass=anon_inode
> >
> > Add a new LSM audit data type holding the inode and the class name.
> >
> > Also warn if the security hook gets called with no name set; currently
> > the only caller fs/anon_inodes.c:anon_inode_make_secure_inode() passes
> > one.
> >
> > Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> > ---
> >  include/linux/lsm_audit.h |  5 +++++
> >  security/lsm_audit.c      | 21 +++++++++++++++++++++
> >  security/selinux/hooks.c  |  7 +++++--
> >  3 files changed, 31 insertions(+), 2 deletions(-)
>
> ...
>
> > diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
> > index 17d02eda9538..8135a88d6d82 100644
> > --- a/include/linux/lsm_audit.h
> > +++ b/include/linux/lsm_audit.h
> > @@ -76,6 +76,7 @@ struct common_audit_data {
> >  #define LSM_AUDIT_DATA_IBENDPORT 14
> >  #define LSM_AUDIT_DATA_LOCKDOWN 15
> >  #define LSM_AUDIT_DATA_NOTIFICATION 16
> > +#define LSM_AUDIT_DATA_ANONINODE       17
> >         union   {
> >                 struct path path;
> >                 struct dentry *dentry;
> > @@ -96,6 +97,10 @@ struct common_audit_data {
> >                 struct lsm_ibpkey_audit *ibpkey;
> >                 struct lsm_ibendport_audit *ibendport;
> >                 int reason;
> > +               struct {
> > +                       struct inode *inode;
> > +                       const char *anonclass;
> > +               } anoninode_struct;
> >         } u;
> >         /* this union contains LSM specific data */
> >         union {
> > diff --git a/security/lsm_audit.c b/security/lsm_audit.c
> > index 1897cbf6fc69..5545fed35539 100644
> > --- a/security/lsm_audit.c
> > +++ b/security/lsm_audit.c
> > @@ -433,6 +433,27 @@ static void dump_common_audit_data(struct audit_buffer *ab,
> >                 audit_log_format(ab, " lockdown_reason=\"%s\"",
> >                                  lockdown_reasons[a->u.reason]);
> >                 break;
> > +       case LSM_AUDIT_DATA_ANONINODE: {
> > +               struct dentry *dentry;
> > +               struct inode *inode;
> > +
> > +               rcu_read_lock();
> > +               inode = a->u.anoninode_struct.inode;
> > +               dentry = d_find_alias_rcu(inode);
> > +               if (dentry) {
> > +                       audit_log_format(ab, " name=");
> > +                       spin_lock(&dentry->d_lock);
> > +                       audit_log_untrustedstring(ab, dentry->d_name.name);
> > +                       spin_unlock(&dentry->d_lock);
> > +               }
>
> I'm not sure we are ever going to get a useful dentry name for
> anonymous inodes, I think we can probably drop this.  The "anonclass="
> field will likely be much more interesting and helpful.
>
> > +               audit_log_format(ab, " anonclass=");
> > +               audit_log_untrustedstring(ab, a->u.anoninode_struct.anonclass);
> > +               audit_log_format(ab, " dev=");
> > +               audit_log_untrustedstring(ab, inode->i_sb->s_id);
>
> I'm pretty sure this is always going to end up being "anon_inodefs"
> and thus not very useful.
>
> > +               audit_log_format(ab, " ino=%lu", inode->i_ino);
>
> Similarly, I'm not sure how useful the inode number is in practice.
> I've never tried, but can a user lookup an anonymous inode via the
> inode number?
>
> > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> > index dafabb4dcc64..19c831d94d9b 100644
> > --- a/security/selinux/hooks.c
> > +++ b/security/selinux/hooks.c
> > @@ -2932,6 +2932,8 @@ static int selinux_inode_init_security_anon(struct inode *inode,
> >         if (unlikely(!selinux_initialized(&selinux_state)))
> >                 return 0;
> >
> > +       WARN_ON(!name);
> > +
> >         isec = selinux_inode(inode);
> >
> >         /*
> > @@ -2965,8 +2967,9 @@ static int selinux_inode_init_security_anon(struct inode *inode,
> >          * allowed to actually create this type of anonymous inode.
> >          */
> >
> > -       ad.type = LSM_AUDIT_DATA_INODE;
> > -       ad.u.inode = inode;
> > +       ad.type = LSM_AUDIT_DATA_ANONINODE;
> > +       ad.u.anoninode_struct.inode = inode;
> > +       ad.u.anoninode_struct.anonclass = name ? (const char *)name->name : "unknown(null)";
>
> This doesn't seem to match well with the newly added WARN_ON()
> assertion above.  I would suggest dropping the WARN_ON() assertion as
> security_transition_sid() can already handle that safely, and leaving
> the tertiary statement above; however I think we should probably
> change the anonclass string to "?" as that is the common unset field
> value used by audit.

Is the hook inode_init_security_anon expected to be called with an
empty name though?
The condition was just a fallback to not crash the kernel.
(Dropped in v2.)

>
> --
> paul-moore.com

Re: [PATCH v2] selinux: log anon inode class name

[Paul Moore]

On Tue, Mar 8, 2022 at 12:09 PM Christian Göttsche
<cgzones@googlemail.com> wrote:
>
> Log the anonymous inode class name in the security hook
> inode_init_security_anon.  This name is the key for name based type
> transitions on the anon_inode security class on creation.  Example:
>
>     type=AVC msg=audit(02/16/22 22:02:50.585:216) : avc:  granted \
>         { create } for  pid=2136 comm=mariadbd anonclass="[io_uring]" \
>         scontext=system_u:system_r:mysqld_t:s0 \
>         tcontext=system_u:system_r:mysqld_iouring_t:s0 tclass=anon_inode
>
> Add a new LSM audit data type holding the inode and the class name.
>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
>
> ---
> v2:
>   - drop dev= and name= output for anonymous inodes, and hence simplify
>     the common_audit_data union member.
>   - drop WARN_ON() on empty name passed to inode_init_security_anon hook
> ---
>  include/linux/lsm_audit.h | 2 ++
>  security/lsm_audit.c      | 4 ++++
>  security/selinux/hooks.c  | 4 ++--
>  3 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
> index 17d02eda9538..97a8b21eb033 100644
> --- a/include/linux/lsm_audit.h
> +++ b/include/linux/lsm_audit.h
> @@ -76,6 +76,7 @@ struct common_audit_data {
>  #define LSM_AUDIT_DATA_IBENDPORT 14
>  #define LSM_AUDIT_DATA_LOCKDOWN 15
>  #define LSM_AUDIT_DATA_NOTIFICATION 16
> +#define LSM_AUDIT_DATA_ANONINODE       17
>         union   {
>                 struct path path;
>                 struct dentry *dentry;
> @@ -96,6 +97,7 @@ struct common_audit_data {
>                 struct lsm_ibpkey_audit *ibpkey;
>                 struct lsm_ibendport_audit *ibendport;
>                 int reason;
> +               const char *anonclass;
>         } u;
>         /* this union contains LSM specific data */
>         union {
> diff --git a/security/lsm_audit.c b/security/lsm_audit.c
> index 1897cbf6fc69..981f6a4e4590 100644
> --- a/security/lsm_audit.c
> +++ b/security/lsm_audit.c
> @@ -433,6 +433,10 @@ static void dump_common_audit_data(struct audit_buffer *ab,
>                 audit_log_format(ab, " lockdown_reason=\"%s\"",
>                                  lockdown_reasons[a->u.reason]);
>                 break;
> +       case LSM_AUDIT_DATA_ANONINODE:
> +               audit_log_format(ab, " anonclass=");
> +               audit_log_untrustedstring(ab, a->u.anonclass);

My apologies, I didn't notice this in the previous patch ... I don't
think we need to log this as an untrusted string as the string value
is coming from the kernel, not userspace, so we could rewrite the
above as the following:

  audit_log_format(ab, " anonclass=%s", a->u.anonclass);

... if you are okay with that, I can make the change when I merge the
patch or you can submit another revision, let me know which you would
prefer.

The rest of the patch looks good, thanks!

> +               break;
>         } /* switch (a->type) */
>  }
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index b12e14b2797b..49c0abfd2f6a 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2965,8 +2965,8 @@ static int selinux_inode_init_security_anon(struct inode *inode,
>          * allowed to actually create this type of anonymous inode.
>          */
>
> -       ad.type = LSM_AUDIT_DATA_INODE;
> -       ad.u.inode = inode;
> +       ad.type = LSM_AUDIT_DATA_ANONINODE;
> +       ad.u.anonclass = name ? (const char *)name->name : "?";
>
>         return avc_has_perm(&selinux_state,
>                             tsec->sid,
> --
> 2.35.1

-- 
paul-moore.com

Re: [PATCH v2] selinux: log anon inode class name

[Paul Moore]

On Mon, Apr 4, 2022 at 4:18 PM Paul Moore <paul@paul-moore.com> wrote:
> On Tue, Mar 8, 2022 at 12:09 PM Christian Göttsche
> <cgzones@googlemail.com> wrote:
> >
> > Log the anonymous inode class name in the security hook
> > inode_init_security_anon.  This name is the key for name based type
> > transitions on the anon_inode security class on creation.  Example:
> >
> >     type=AVC msg=audit(02/16/22 22:02:50.585:216) : avc:  granted \
> >         { create } for  pid=2136 comm=mariadbd anonclass="[io_uring]" \
> >         scontext=system_u:system_r:mysqld_t:s0 \
> >         tcontext=system_u:system_r:mysqld_iouring_t:s0 tclass=anon_inode
> >
> > Add a new LSM audit data type holding the inode and the class name.
> >
> > Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> >
> > ---
> > v2:
> >   - drop dev= and name= output for anonymous inodes, and hence simplify
> >     the common_audit_data union member.
> >   - drop WARN_ON() on empty name passed to inode_init_security_anon hook
> > ---
> >  include/linux/lsm_audit.h | 2 ++
> >  security/lsm_audit.c      | 4 ++++
> >  security/selinux/hooks.c  | 4 ++--
> >  3 files changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
> > index 17d02eda9538..97a8b21eb033 100644
> > --- a/include/linux/lsm_audit.h
> > +++ b/include/linux/lsm_audit.h
> > @@ -76,6 +76,7 @@ struct common_audit_data {
> >  #define LSM_AUDIT_DATA_IBENDPORT 14
> >  #define LSM_AUDIT_DATA_LOCKDOWN 15
> >  #define LSM_AUDIT_DATA_NOTIFICATION 16
> > +#define LSM_AUDIT_DATA_ANONINODE       17
> >         union   {
> >                 struct path path;
> >                 struct dentry *dentry;
> > @@ -96,6 +97,7 @@ struct common_audit_data {
> >                 struct lsm_ibpkey_audit *ibpkey;
> >                 struct lsm_ibendport_audit *ibendport;
> >                 int reason;
> > +               const char *anonclass;
> >         } u;
> >         /* this union contains LSM specific data */
> >         union {
> > diff --git a/security/lsm_audit.c b/security/lsm_audit.c
> > index 1897cbf6fc69..981f6a4e4590 100644
> > --- a/security/lsm_audit.c
> > +++ b/security/lsm_audit.c
> > @@ -433,6 +433,10 @@ static void dump_common_audit_data(struct audit_buffer *ab,
> >                 audit_log_format(ab, " lockdown_reason=\"%s\"",
> >                                  lockdown_reasons[a->u.reason]);
> >                 break;
> > +       case LSM_AUDIT_DATA_ANONINODE:
> > +               audit_log_format(ab, " anonclass=");
> > +               audit_log_untrustedstring(ab, a->u.anonclass);
>
> My apologies, I didn't notice this in the previous patch ... I don't
> think we need to log this as an untrusted string as the string value
> is coming from the kernel, not userspace, so we could rewrite the
> above as the following:
>
>   audit_log_format(ab, " anonclass=%s", a->u.anonclass);
>
> ... if you are okay with that, I can make the change when I merge the
> patch or you can submit another revision, let me know which you would
> prefer.
>
> The rest of the patch looks good, thanks!

Hi Christian,

I just wanted to follow up on this as we are at -rc4 this week and if
we want this to go during the next merge window this would need to be
merged soon ...

-- 
paul-moore.com

Re: [PATCH v2] selinux: log anon inode class name

[Christian Göttsche]

On Wed, 27 Apr 2022 at 15:19, Paul Moore <paul@paul-moore.com> wrote:
>
> On Mon, Apr 4, 2022 at 4:18 PM Paul Moore <paul@paul-moore.com> wrote:
> > On Tue, Mar 8, 2022 at 12:09 PM Christian Göttsche
> > <cgzones@googlemail.com> wrote:
> > >
> > > Log the anonymous inode class name in the security hook
> > > inode_init_security_anon.  This name is the key for name based type
> > > transitions on the anon_inode security class on creation.  Example:
> > >
> > >     type=AVC msg=audit(02/16/22 22:02:50.585:216) : avc:  granted \
> > >         { create } for  pid=2136 comm=mariadbd anonclass="[io_uring]" \
> > >         scontext=system_u:system_r:mysqld_t:s0 \
> > >         tcontext=system_u:system_r:mysqld_iouring_t:s0 tclass=anon_inode
> > >
> > > Add a new LSM audit data type holding the inode and the class name.
> > >
> > > Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> > >
> > > ---
> > > v2:
> > >   - drop dev= and name= output for anonymous inodes, and hence simplify
> > >     the common_audit_data union member.
> > >   - drop WARN_ON() on empty name passed to inode_init_security_anon hook
> > > ---
> > >  include/linux/lsm_audit.h | 2 ++
> > >  security/lsm_audit.c      | 4 ++++
> > >  security/selinux/hooks.c  | 4 ++--
> > >  3 files changed, 8 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
> > > index 17d02eda9538..97a8b21eb033 100644
> > > --- a/include/linux/lsm_audit.h
> > > +++ b/include/linux/lsm_audit.h
> > > @@ -76,6 +76,7 @@ struct common_audit_data {
> > >  #define LSM_AUDIT_DATA_IBENDPORT 14
> > >  #define LSM_AUDIT_DATA_LOCKDOWN 15
> > >  #define LSM_AUDIT_DATA_NOTIFICATION 16
> > > +#define LSM_AUDIT_DATA_ANONINODE       17
> > >         union   {
> > >                 struct path path;
> > >                 struct dentry *dentry;
> > > @@ -96,6 +97,7 @@ struct common_audit_data {
> > >                 struct lsm_ibpkey_audit *ibpkey;
> > >                 struct lsm_ibendport_audit *ibendport;
> > >                 int reason;
> > > +               const char *anonclass;
> > >         } u;
> > >         /* this union contains LSM specific data */
> > >         union {
> > > diff --git a/security/lsm_audit.c b/security/lsm_audit.c
> > > index 1897cbf6fc69..981f6a4e4590 100644
> > > --- a/security/lsm_audit.c
> > > +++ b/security/lsm_audit.c
> > > @@ -433,6 +433,10 @@ static void dump_common_audit_data(struct audit_buffer *ab,
> > >                 audit_log_format(ab, " lockdown_reason=\"%s\"",
> > >                                  lockdown_reasons[a->u.reason]);
> > >                 break;
> > > +       case LSM_AUDIT_DATA_ANONINODE:
> > > +               audit_log_format(ab, " anonclass=");
> > > +               audit_log_untrustedstring(ab, a->u.anonclass);
> >
> > My apologies, I didn't notice this in the previous patch ... I don't
> > think we need to log this as an untrusted string as the string value
> > is coming from the kernel, not userspace, so we could rewrite the
> > above as the following:
> >
> >   audit_log_format(ab, " anonclass=%s", a->u.anonclass);
> >
> > ... if you are okay with that, I can make the change when I merge the
> > patch or you can submit another revision, let me know which you would
> > prefer.

Feel free to adjust while merging, thanks.

> >
> > The rest of the patch looks good, thanks!
>
> Hi Christian,
>
> I just wanted to follow up on this as we are at -rc4 this week and if
> we want this to go during the next merge window this would need to be
> merged soon ...
>
> --
> paul-moore.com

Re: [PATCH v2] selinux: log anon inode class name

[Paul Moore]

On Mon, May 2, 2022 at 9:39 AM Christian Göttsche
<cgzones@googlemail.com> wrote:
> On Wed, 27 Apr 2022 at 15:19, Paul Moore <paul@paul-moore.com> wrote:
> > On Mon, Apr 4, 2022 at 4:18 PM Paul Moore <paul@paul-moore.com> wrote:
> > > On Tue, Mar 8, 2022 at 12:09 PM Christian Göttsche
> > > <cgzones@googlemail.com> wrote:
> > > >
> > > > Log the anonymous inode class name in the security hook
> > > > inode_init_security_anon.  This name is the key for name based type
> > > > transitions on the anon_inode security class on creation.  Example:
> > > >
> > > >     type=AVC msg=audit(02/16/22 22:02:50.585:216) : avc:  granted \
> > > >         { create } for  pid=2136 comm=mariadbd anonclass="[io_uring]" \
> > > >         scontext=system_u:system_r:mysqld_t:s0 \
> > > >         tcontext=system_u:system_r:mysqld_iouring_t:s0 tclass=anon_inode
> > > >
> > > > Add a new LSM audit data type holding the inode and the class name.
> > > >
> > > > Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> > > >
> > > > ---
> > > > v2:
> > > >   - drop dev= and name= output for anonymous inodes, and hence simplify
> > > >     the common_audit_data union member.
> > > >   - drop WARN_ON() on empty name passed to inode_init_security_anon hook
> > > > ---
> > > >  include/linux/lsm_audit.h | 2 ++
> > > >  security/lsm_audit.c      | 4 ++++
> > > >  security/selinux/hooks.c  | 4 ++--
> > > >  3 files changed, 8 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
> > > > index 17d02eda9538..97a8b21eb033 100644
> > > > --- a/include/linux/lsm_audit.h
> > > > +++ b/include/linux/lsm_audit.h
> > > > @@ -76,6 +76,7 @@ struct common_audit_data {
> > > >  #define LSM_AUDIT_DATA_IBENDPORT 14
> > > >  #define LSM_AUDIT_DATA_LOCKDOWN 15
> > > >  #define LSM_AUDIT_DATA_NOTIFICATION 16
> > > > +#define LSM_AUDIT_DATA_ANONINODE       17
> > > >         union   {
> > > >                 struct path path;
> > > >                 struct dentry *dentry;
> > > > @@ -96,6 +97,7 @@ struct common_audit_data {
> > > >                 struct lsm_ibpkey_audit *ibpkey;
> > > >                 struct lsm_ibendport_audit *ibendport;
> > > >                 int reason;
> > > > +               const char *anonclass;
> > > >         } u;
> > > >         /* this union contains LSM specific data */
> > > >         union {
> > > > diff --git a/security/lsm_audit.c b/security/lsm_audit.c
> > > > index 1897cbf6fc69..981f6a4e4590 100644
> > > > --- a/security/lsm_audit.c
> > > > +++ b/security/lsm_audit.c
> > > > @@ -433,6 +433,10 @@ static void dump_common_audit_data(struct audit_buffer *ab,
> > > >                 audit_log_format(ab, " lockdown_reason=\"%s\"",
> > > >                                  lockdown_reasons[a->u.reason]);
> > > >                 break;
> > > > +       case LSM_AUDIT_DATA_ANONINODE:
> > > > +               audit_log_format(ab, " anonclass=");
> > > > +               audit_log_untrustedstring(ab, a->u.anonclass);
> > >
> > > My apologies, I didn't notice this in the previous patch ... I don't
> > > think we need to log this as an untrusted string as the string value
> > > is coming from the kernel, not userspace, so we could rewrite the
> > > above as the following:
> > >
> > >   audit_log_format(ab, " anonclass=%s", a->u.anonclass);
> > >
> > > ... if you are okay with that, I can make the change when I merge the
> > > patch or you can submit another revision, let me know which you would
> > > prefer.
>
> Feel free to adjust while merging, thanks.

Adjusted and merged, thanks.

-- 
paul-moore.com