[PATCH 1/1] selinux: add the processing of the failure of avc_add_xperms_decision()

[PATCH 1/1] selinux: add the processing of the failure of avc_add_xperms_decision()

[thunder.leizhen]

From: Zhen Lei <thunder.leizhen@huawei.com>

When avc_add_xperms_decision() fails, the information recorded by the new
avc node is incomplete. In this case, the new avc node should be released
instead of replacing the old avc node.

Fixes: fa1aa143ac4a ("selinux: extended permissions for ioctls")
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 security/selinux/avc.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 7087cd2b802d8d8..b49c44869dc4627 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -907,7 +907,11 @@ static int avc_update_node(u32 event, u32 perms, u8 driver, u8 xperm, u32 ssid,
 		node->ae.avd.auditdeny &= ~perms;
 		break;
 	case AVC_CALLBACK_ADD_XPERMS:
-		avc_add_xperms_decision(node, xpd);
+		rc = avc_add_xperms_decision(node, xpd);
+		if (rc) {
+			avc_node_kill(node);
+			goto out_unlock;
+		}
 		break;
 	}
 	avc_node_replace(node, orig);
-- 
2.34.1

Re: [PATCH 1/1] selinux: add the processing of the failure of avc_add_xperms_decision()

[Stephen Smalley]

On Wed, Aug 7, 2024 at 5:02 AM <thunder.leizhen@huaweicloud.com> wrote:
>
> From: Zhen Lei <thunder.leizhen@huawei.com>
>
> When avc_add_xperms_decision() fails, the information recorded by the new
> avc node is incomplete. In this case, the new avc node should be released
> instead of replacing the old avc node.
>
> Fixes: fa1aa143ac4a ("selinux: extended permissions for ioctls")
> Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>

Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>

> ---
>  security/selinux/avc.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/security/selinux/avc.c b/security/selinux/avc.c
> index 7087cd2b802d8d8..b49c44869dc4627 100644
> --- a/security/selinux/avc.c
> +++ b/security/selinux/avc.c
> @@ -907,7 +907,11 @@ static int avc_update_node(u32 event, u32 perms, u8 driver, u8 xperm, u32 ssid,
>                 node->ae.avd.auditdeny &= ~perms;
>                 break;
>         case AVC_CALLBACK_ADD_XPERMS:
> -               avc_add_xperms_decision(node, xpd);
> +               rc = avc_add_xperms_decision(node, xpd);
> +               if (rc) {
> +                       avc_node_kill(node);
> +                       goto out_unlock;
> +               }
>                 break;
>         }
>         avc_node_replace(node, orig);
> --
> 2.34.1
>

Re: [PATCH 1/1] selinux: add the processing of the failure of avc_add_xperms_decision()

[Paul Moore]

On Aug  7, 2024 thunder.leizhen@huaweicloud.com wrote:
> 
> When avc_add_xperms_decision() fails, the information recorded by the new
> avc node is incomplete. In this case, the new avc node should be released
> instead of replacing the old avc node.
> 
> Fixes: fa1aa143ac4a ("selinux: extended permissions for ioctls")
> Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
> ---
>  security/selinux/avc.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

Thanks, this looks good to me.  I'm going to merge this into
selinux/stable-6.11 with the idea of sending it, and your other
patch, up to Linus tomorrow, or potentially next week.

Thanks for your help!

--
paul-moore.com