diff mbox series

selinux,smack: properly reference the LSM blob in security_watch_key()

Message ID 20240919155740.29539-2-paul@paul-moore.com (mailing list archive)
State Accepted
Delegated to: Paul Moore
Headers show
Series selinux,smack: properly reference the LSM blob in security_watch_key() | expand

Commit Message

Paul Moore Sept. 19, 2024, 3:57 p.m. UTC
Unfortunately when we migrated the lifecycle management of the key LSM
blob to the LSM framework we forgot to convert the security_watch_key()
callbacks for SELinux and Smack.  This patch corrects this by making use
of the selinux_key() and smack_key() helper functions respectively.

This patch also removes some input checking in the Smack callback as it
is no longer needed.

Reported-by: syzbot+044fdf24e96093584232@syzkaller.appspotmail.com
Fixes: 5f8d28f6d7d5 ("lsm: infrastructure management of the key security blob")
Signed-off-by: Paul Moore <paul@paul-moore.com>
---
 security/selinux/hooks.c   |  2 +-
 security/smack/smack_lsm.c | 13 +++----------
 2 files changed, 4 insertions(+), 11 deletions(-)

Comments

Casey Schaufler Sept. 19, 2024, 4:34 p.m. UTC | #1
On 9/19/2024 8:57 AM, Paul Moore wrote:
> Unfortunately when we migrated the lifecycle management of the key LSM
> blob to the LSM framework we forgot to convert the security_watch_key()
> callbacks for SELinux and Smack.  This patch corrects this by making use
> of the selinux_key() and smack_key() helper functions respectively.
>
> This patch also removes some input checking in the Smack callback as it
> is no longer needed.
>
> Reported-by: syzbot+044fdf24e96093584232@syzkaller.appspotmail.com
> Fixes: 5f8d28f6d7d5 ("lsm: infrastructure management of the key security blob")
> Signed-off-by: Paul Moore <paul@paul-moore.com>

Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>

> ---
>  security/selinux/hooks.c   |  2 +-
>  security/smack/smack_lsm.c | 13 +++----------
>  2 files changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 81fbfa5b80d4..67baa487cf7a 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -6720,7 +6720,7 @@ static int selinux_key_getsecurity(struct key *key, char **_buffer)
>  #ifdef CONFIG_KEY_NOTIFICATIONS
>  static int selinux_watch_key(struct key *key)
>  {
> -	struct key_security_struct *ksec = key->security;
> +	struct key_security_struct *ksec = selinux_key(key);
>  	u32 sid = current_sid();
>  
>  	return avc_has_perm(sid, ksec->sid, SECCLASS_KEY, KEY__VIEW, NULL);
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index da0c2bffbd08..563fb404f659 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -4629,16 +4629,9 @@ static int smack_watch_key(struct key *key)
>  {
>  	struct smk_audit_info ad;
>  	struct smack_known *tkp = smk_of_current();
> +	struct smack_known **blob = smack_key(key);
>  	int rc;
>  
> -	if (key == NULL)
> -		return -EINVAL;
> -	/*
> -	 * If the key hasn't been initialized give it access so that
> -	 * it may do so.
> -	 */
> -	if (key->security == NULL)
> -		return 0;
>  	/*
>  	 * This should not occur
>  	 */
> @@ -4653,8 +4646,8 @@ static int smack_watch_key(struct key *key)
>  	ad.a.u.key_struct.key = key->serial;
>  	ad.a.u.key_struct.key_desc = key->description;
>  #endif
> -	rc = smk_access(tkp, key->security, MAY_READ, &ad);
> -	rc = smk_bu_note("key watch", tkp, key->security, MAY_READ, rc);
> +	rc = smk_access(tkp, *blob, MAY_READ, &ad);
> +	rc = smk_bu_note("key watch", tkp, *blob, MAY_READ, rc);
>  	return rc;
>  }
>  #endif /* CONFIG_KEY_NOTIFICATIONS */
Paul Moore Sept. 19, 2024, 8:40 p.m. UTC | #2
On Thu, Sep 19, 2024 at 12:34 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 9/19/2024 8:57 AM, Paul Moore wrote:
> > Unfortunately when we migrated the lifecycle management of the key LSM
> > blob to the LSM framework we forgot to convert the security_watch_key()
> > callbacks for SELinux and Smack.  This patch corrects this by making use
> > of the selinux_key() and smack_key() helper functions respectively.
> >
> > This patch also removes some input checking in the Smack callback as it
> > is no longer needed.
> >
> > Reported-by: syzbot+044fdf24e96093584232@syzkaller.appspotmail.com
> > Fixes: 5f8d28f6d7d5 ("lsm: infrastructure management of the key security blob")
> > Signed-off-by: Paul Moore <paul@paul-moore.com>
>
> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>

Thanks for the quick review, it looks like syzbot was happy with the
patch too so I've merged this into lsm/stable-6.12 and I'll send it up
to Linus soon.
diff mbox series

Patch

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 81fbfa5b80d4..67baa487cf7a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6720,7 +6720,7 @@  static int selinux_key_getsecurity(struct key *key, char **_buffer)
 #ifdef CONFIG_KEY_NOTIFICATIONS
 static int selinux_watch_key(struct key *key)
 {
-	struct key_security_struct *ksec = key->security;
+	struct key_security_struct *ksec = selinux_key(key);
 	u32 sid = current_sid();
 
 	return avc_has_perm(sid, ksec->sid, SECCLASS_KEY, KEY__VIEW, NULL);
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index da0c2bffbd08..563fb404f659 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4629,16 +4629,9 @@  static int smack_watch_key(struct key *key)
 {
 	struct smk_audit_info ad;
 	struct smack_known *tkp = smk_of_current();
+	struct smack_known **blob = smack_key(key);
 	int rc;
 
-	if (key == NULL)
-		return -EINVAL;
-	/*
-	 * If the key hasn't been initialized give it access so that
-	 * it may do so.
-	 */
-	if (key->security == NULL)
-		return 0;
 	/*
 	 * This should not occur
 	 */
@@ -4653,8 +4646,8 @@  static int smack_watch_key(struct key *key)
 	ad.a.u.key_struct.key = key->serial;
 	ad.a.u.key_struct.key_desc = key->description;
 #endif
-	rc = smk_access(tkp, key->security, MAY_READ, &ad);
-	rc = smk_bu_note("key watch", tkp, key->security, MAY_READ, rc);
+	rc = smk_access(tkp, *blob, MAY_READ, &ad);
+	rc = smk_bu_note("key watch", tkp, *blob, MAY_READ, rc);
 	return rc;
 }
 #endif /* CONFIG_KEY_NOTIFICATIONS */