From: Casey Schaufler <casey@schaufler-ca.com>
To: casey.schaufler@intel.com, jmorris@namei.org,
linux-security-module@vger.kernel.org, selinux@vger.kernel.org
Cc: john.johansen@canonical.com, linux-kernel@vger.kernel.org,
linux-audit@redhat.com, sds@tycho.nsa.gov
Subject: [PATCH v29 20/28] LSM: Verify LSM display sanity in binder
Date: Fri, 24 Sep 2021 10:54:33 -0700 [thread overview]
Message-ID: <20210924175441.7943-21-casey@schaufler-ca.com> (raw)
In-Reply-To: <20210924175441.7943-1-casey@schaufler-ca.com>
Verify that the tasks on the ends of a binder transaction
use the same "interface_lsm" security module. This prevents
confusion of security "contexts".
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
security/security.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/security/security.c b/security/security.c
index a61477c6b0f6..155da0e9b778 100644
--- a/security/security.c
+++ b/security/security.c
@@ -860,9 +860,38 @@ int security_binder_set_context_mgr(struct task_struct *mgr)
return call_int_hook(binder_set_context_mgr, 0, mgr);
}
+/**
+ * security_binder_transaction - Binder driver transaction check
+ * @from: source of the transaction
+ * @to: destination of the transaction
+ *
+ * Verify that the tasks have the same LSM "display", then
+ * call the security module hooks.
+ *
+ * Returns -EINVAL if the displays don't match, or the
+ * result of the security module checks.
+ */
int security_binder_transaction(struct task_struct *from,
struct task_struct *to)
{
+ int from_ilsm = lsm_task_ilsm(from);
+ int to_ilsm = lsm_task_ilsm(to);
+
+ /*
+ * If the ilsm is LSMBLOB_INVALID the first module that has
+ * an entry is used. This will be in the 0 slot.
+ *
+ * This is currently only required if the server has requested
+ * peer contexts, but it would be unwieldly to have too much of
+ * the binder driver detail here.
+ */
+ if (from_ilsm == LSMBLOB_INVALID)
+ from_ilsm = 0;
+ if (to_ilsm == LSMBLOB_INVALID)
+ to_ilsm = 0;
+ if (from_ilsm != to_ilsm)
+ return -EINVAL;
+
return call_int_hook(binder_transaction, 0, from, to);
}
--
2.31.1
--
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next prev parent reply other threads:[~2021-09-24 18:17 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210924175441.7943-1-casey.ref@schaufler-ca.com>
2021-09-24 17:54 ` [PATCH v29 00/28] LSM: Module stacking for AppArmor Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 01/28] LSM: Infrastructure management of the sock security Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 02/28] LSM: Add the lsmblob data structure Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 03/28] LSM: provide lsm name and id slot mappings Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 04/28] IMA: avoid label collisions with stacked LSMs Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 05/28] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 06/28] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 07/28] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 08/28] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 09/28] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 10/28] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 11/28] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 12/28] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 13/28] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 14/28] LSM: Specify which LSM to display Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 15/28] LSM: Ensure the correct LSM context releaser Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 16/28] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 17/28] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 18/28] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 19/28] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2021-09-24 17:54 ` Casey Schaufler [this message]
2021-09-24 17:54 ` [PATCH v29 21/28] LSM: Extend security_secid_to_secctx to include module selection Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 22/28] Audit: Keep multiple LSM data in audit_names Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 23/28] Audit: Create audit_stamp structure Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 24/28] Audit: Add framework for auxiliary records Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 25/28] Audit: Add record for multiple task security contexts Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 26/28] Audit: Add record for multiple object " Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 27/28] LSM: Add /proc attr entry for full LSM context Casey Schaufler
2021-09-24 17:54 ` [PATCH v29 28/28] AppArmor: Remove the exclusive flag Casey Schaufler
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