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 v28 20/25] LSM: Verify LSM display sanity in binder
Date: Wed, 21 Jul 2021 17:47:53 -0700 [thread overview]
Message-ID: <20210722004758.12371-21-casey@schaufler-ca.com> (raw)
In-Reply-To: <20210722004758.12371-1-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 <sds@tycho.nsa.gov>
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 13ded9c55344..cb359e185d1a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -859,9 +859,38 @@ 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:[~2021-07-22 1:10 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210722004758.12371-1-casey.ref@schaufler-ca.com>
2021-07-22 0:47 ` [PATCH v28 00/25] LSM: Module stacking for AppArmor Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 01/25] LSM: Infrastructure management of the sock security Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 02/25] LSM: Add the lsmblob data structure Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 03/25] LSM: provide lsm name and id slot mappings Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 04/25] IMA: avoid label collisions with stacked LSMs Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 05/25] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 06/25] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 07/25] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 08/25] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 09/25] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 10/25] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 11/25] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 12/25] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2021-07-23 23:56 ` kernel test robot
2021-07-22 0:47 ` [PATCH v28 13/25] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 14/25] LSM: Specify which LSM to display Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 15/25] LSM: Ensure the correct LSM context releaser Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 16/25] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 17/25] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 18/25] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 19/25] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2021-07-22 0:47 ` Casey Schaufler [this message]
2021-07-22 0:47 ` [PATCH v28 21/25] audit: support non-syscall auxiliary records Casey Schaufler
2021-07-22 17:02 ` kernel test robot
2021-07-22 0:47 ` [PATCH v28 22/25] Audit: Add record for multiple process LSM attributes Casey Schaufler
2021-07-22 4:08 ` kernel test robot
2021-08-12 20:59 ` Paul Moore
2021-08-12 22:38 ` Casey Schaufler
2021-08-13 15:31 ` Paul Moore
2021-08-13 18:48 ` Casey Schaufler
2021-08-13 20:43 ` Paul Moore
2021-08-13 21:47 ` Casey Schaufler
2021-08-16 18:57 ` Paul Moore
2021-08-18 21:59 ` Casey Schaufler
2021-08-19 0:47 ` Paul Moore
2021-08-19 0:56 ` Casey Schaufler
2021-08-19 22:41 ` Casey Schaufler
2021-08-20 19:06 ` Paul Moore
2021-08-20 19:17 ` Casey Schaufler
2021-08-20 23:48 ` Casey Schaufler
2021-08-24 14:45 ` Paul Moore
2021-08-24 15:20 ` Casey Schaufler
2021-08-24 16:14 ` Paul Moore
2021-07-22 0:47 ` [PATCH v28 23/25] Audit: Add record for multiple object " Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 24/25] LSM: Add /proc attr entry for full LSM context Casey Schaufler
2021-07-22 0:47 ` [PATCH v28 25/25] AppArmor: Remove the exclusive flag Casey Schaufler
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