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-audit@redhat.com, sds@tycho.nsa.gov
Subject: [PATCH v20 19/23] LSM: Verify LSM display sanity in binder
Date: Wed, 26 Aug 2020 07:52:43 -0700 [thread overview]
Message-ID: <20200826145247.10029-20-casey@schaufler-ca.com> (raw)
In-Reply-To: <20200826145247.10029-1-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
--
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next prev parent reply other threads:[~2020-08-26 15:22 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200826145247.10029-1-casey.ref@schaufler-ca.com>
2020-08-26 14:52 ` [PATCH v20 00/23] LSM: Module stacking for AppArmor Casey Schaufler
2020-08-26 14:52 ` [PATCH v20 01/23] LSM: Infrastructure management of the sock security Casey Schaufler
2020-08-26 14:52 ` [PATCH v20 02/23] LSM: Create and manage the lsmblob data structure Casey Schaufler
2020-09-04 21:50 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 03/23] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2020-09-04 18:53 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 04/23] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2020-09-04 19:46 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 05/23] net: Prepare UDS for security module stacking Casey Schaufler
2020-09-03 16:28 ` James Morris
2020-09-04 20:08 ` Paul Moore
2020-09-04 21:35 ` Casey Schaufler
2020-09-04 21:53 ` Paul Moore
2020-09-04 23:58 ` Casey Schaufler
2020-09-05 13:25 ` Paul Moore
2020-09-05 18:13 ` Casey Schaufler
2020-09-05 19:05 ` John Johansen
2020-09-08 1:28 ` Stephen Smalley
2020-09-08 13:35 ` Stephen Smalley
2020-09-08 23:37 ` Casey Schaufler
2020-09-09 0:21 ` John Johansen
2020-09-09 13:19 ` Stephen Smalley
2020-09-09 18:19 ` Casey Schaufler
2020-09-09 18:33 ` John Johansen
2020-09-09 18:47 ` John Johansen
2020-09-10 14:11 ` Paul Moore
2020-09-09 0:17 ` John Johansen
2020-08-26 14:52 ` [PATCH v20 06/23] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2020-09-04 21:29 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 07/23] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2020-09-04 21:59 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 08/23] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2020-09-05 13:12 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 09/23] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2020-09-05 13:18 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 10/23] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2020-09-05 13:20 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 11/23] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2020-08-26 14:52 ` [PATCH v20 12/23] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2020-09-06 2:28 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 13/23] LSM: Specify which LSM to display Casey Schaufler
2020-08-26 14:52 ` [PATCH v20 14/23] LSM: Ensure the correct LSM context releaser Casey Schaufler
2020-09-06 2:45 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 15/23] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2020-08-26 14:52 ` [PATCH v20 16/23] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2020-09-06 2:55 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 17/23] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2020-09-06 3:11 ` Paul Moore
2020-09-08 10:46 ` Pablo Neira Ayuso
2020-08-26 14:52 ` [PATCH v20 18/23] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2020-09-06 3:27 ` Paul Moore
2020-08-26 14:52 ` Casey Schaufler [this message]
2020-09-06 3:30 ` [PATCH v20 19/23] LSM: Verify LSM display sanity in binder Paul Moore
2020-08-26 14:52 ` [PATCH v20 20/23] Audit: Add new record for multiple process LSM attributes Casey Schaufler
2020-09-03 16:32 ` James Morris
2020-09-03 17:00 ` John Johansen
2020-09-03 21:49 ` Paul Moore
2020-09-06 16:32 ` Paul Moore
2020-08-26 14:52 ` [PATCH v20 21/23] Audit: Add a new record for multiple object " Casey Schaufler
2020-08-26 14:52 ` [PATCH v20 22/23] LSM: Add /proc attr entry for full LSM context Casey Schaufler
2020-08-26 18:02 ` Randy Dunlap
2020-08-26 14:52 ` [PATCH v20 23/23] AppArmor: Remove the exclusive flag Casey Schaufler
2020-08-26 15:27 ` [PATCH v20 00/23] LSM: Module stacking for AppArmor Casey Schaufler
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