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: casey@schaufler-ca.com, linux-audit@redhat.com,
keescook@chromium.org, john.johansen@canonical.com,
penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com,
sds@tycho.nsa.gov
Subject: [PATCH v19 19/23] LSM: Verify LSM display sanity in binder
Date: Fri, 24 Jul 2020 13:32:22 -0700 [thread overview]
Message-ID: <20200724203226.16374-20-casey@schaufler-ca.com> (raw)
In-Reply-To: <20200724203226.16374-1-casey@schaufler-ca.com>
Verify that the tasks on the ends of a binder transaction
use the same "display" security module. This prevents confusion
of security "contexts".
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
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 ddbaf2073b02..95b48721fb17 100644
--- a/security/security.c
+++ b/security/security.c
@@ -788,9 +788,38 @@ 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_display = lsm_task_display(from);
+ int to_display = lsm_task_display(to);
+
+ /*
+ * If the display 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_display == LSMBLOB_INVALID)
+ from_display = 0;
+ if (to_display == LSMBLOB_INVALID)
+ to_display = 0;
+ if (from_display != to_display)
+ return -EINVAL;
+
return call_int_hook(binder_transaction, 0, from, to);
}
--
2.24.1
next prev parent reply other threads:[~2020-07-24 20:53 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200724203226.16374-1-casey.ref@schaufler-ca.com>
2020-07-24 20:32 ` [PATCH v19 00/23] LSM: Module stacking for AppArmor Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 01/23] LSM: Infrastructure management of the sock security Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 02/23] LSM: Create and manage the lsmblob data structure Casey Schaufler
2020-07-27 16:12 ` Stephen Smalley
2020-07-27 21:04 ` Casey Schaufler
2020-07-28 19:50 ` John Johansen
2020-07-24 20:32 ` [PATCH v19 03/23] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 04/23] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2020-07-28 10:34 ` John Johansen
2020-07-24 20:32 ` [PATCH v19 05/23] net: Prepare UDS for security module stacking Casey Schaufler
2020-07-28 10:57 ` John Johansen
2020-07-24 20:32 ` [PATCH v19 06/23] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2020-07-28 11:11 ` John Johansen
2020-07-28 23:41 ` Casey Schaufler
2020-07-29 0:30 ` John Johansen
2020-07-24 20:32 ` [PATCH v19 07/23] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 08/23] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 09/23] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 10/23] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 11/23] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 12/23] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 13/23] LSM: Specify which LSM to display Casey Schaufler
2020-07-27 20:36 ` James Morris
2020-07-27 20:40 ` John Johansen
2020-07-28 18:29 ` John Johansen
2020-07-24 20:32 ` [PATCH v19 14/23] LSM: Ensure the correct LSM context releaser Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 15/23] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2020-07-28 20:13 ` John Johansen
2020-07-24 20:32 ` [PATCH v19 16/23] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2020-07-28 20:28 ` John Johansen
2020-07-24 20:32 ` [PATCH v19 17/23] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2020-07-27 20:37 ` James Morris
2020-07-24 20:32 ` [PATCH v19 18/23] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2020-07-24 20:32 ` Casey Schaufler [this message]
2020-07-30 8:40 ` [PATCH v19 19/23] LSM: Verify LSM display sanity in binder John Johansen
2020-07-24 20:32 ` [PATCH v19 20/23] Audit: Add new record for multiple process LSM attributes Casey Schaufler
2020-07-27 19:04 ` Stephen Smalley
2020-07-24 20:32 ` [PATCH v19 21/23] Audit: Add a new record for multiple object " Casey Schaufler
2020-07-27 20:40 ` James Morris
2020-07-24 20:32 ` [PATCH v19 22/23] LSM: Add /proc attr entry for full LSM context Casey Schaufler
2020-07-30 10:03 ` John Johansen
2020-07-30 20:44 ` Casey Schaufler
2020-07-30 20:57 ` John Johansen
2020-07-30 22:22 ` Casey Schaufler
2020-07-24 20:32 ` [PATCH v19 23/23] AppArmor: Remove the exclusive flag Casey Schaufler
2020-07-30 9:23 ` John Johansen
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