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, keescook@chromium.org,
john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp,
paul@paul-moore.com, sds@tycho.nsa.gov, linux-audit@redhat.com
Subject: [PATCH v16 19/23] LSM: Verify LSM display sanity in binder
Date: Mon, 6 Apr 2020 17:01:55 -0700 [thread overview]
Message-ID: <20200407000159.43602-20-casey@schaufler-ca.com> (raw)
In-Reply-To: <20200407000159.43602-1-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".
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 84f33bd4990a..b7c2ed1eee42 100644
--- a/security/security.c
+++ b/security/security.c
@@ -769,9 +769,38 @@ 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
WARNING: multiple messages have this Message-ID (diff)
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 v16 19/23] LSM: Verify LSM display sanity in binder
Date: Mon, 6 Apr 2020 17:01:55 -0700 [thread overview]
Message-ID: <20200407000159.43602-20-casey@schaufler-ca.com> (raw)
In-Reply-To: <20200407000159.43602-1-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".
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 84f33bd4990a..b7c2ed1eee42 100644
--- a/security/security.c
+++ b/security/security.c
@@ -769,9 +769,38 @@ 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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https://www.redhat.com/mailman/listinfo/linux-audit
next prev parent reply other threads:[~2020-04-07 0:22 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200407000159.43602-1-casey.ref@schaufler-ca.com>
2020-04-07 0:01 ` [PATCH v16 00/23] LSM: Module stacking for AppArmor Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 01/23] LSM: Infrastructure management of the sock security Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 02/23] LSM: Create and manage the lsmblob data structure Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 03/23] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 04/23] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 05/23] net: Prepare UDS for security module stacking Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 18:36 ` Kees Cook
2020-04-07 18:36 ` Kees Cook
2020-04-07 0:01 ` [PATCH v16 06/23] Use lsmblob in security_secctx_to_secid Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 18:36 ` Kees Cook
2020-04-07 18:36 ` Kees Cook
2020-04-07 0:01 ` [PATCH v16 07/23] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 08/23] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 09/23] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 10/23] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 11/23] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 12/23] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 13/23] LSM: Specify which LSM to display Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 18:40 ` Kees Cook
2020-04-07 18:40 ` Kees Cook
2020-04-07 0:01 ` [PATCH v16 14/23] LSM: Ensure the correct LSM context releaser Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 15/23] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 18:41 ` Kees Cook
2020-04-07 18:41 ` Kees Cook
2020-04-07 0:01 ` [PATCH v16 16/23] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 18:41 ` Kees Cook
2020-04-07 18:41 ` Kees Cook
2020-04-07 0:01 ` [PATCH v16 17/23] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` [PATCH v16 18/23] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler [this message]
2020-04-07 0:01 ` [PATCH v16 19/23] LSM: Verify LSM display sanity in binder Casey Schaufler
2020-04-07 18:42 ` Kees Cook
2020-04-07 18:42 ` Kees Cook
2020-04-07 0:01 ` [PATCH v16 20/23] Audit: Add a new record for multiple subject LSM attributes Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 18:43 ` Kees Cook
2020-04-07 18:43 ` Kees Cook
2020-04-07 0:01 ` [PATCH v16 21/23] Audit: Add a new record for multiple object " Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 18:43 ` Kees Cook
2020-04-07 18:43 ` Kees Cook
2020-04-07 0:01 ` [PATCH v16 22/23] LSM: Add /proc attr entry for full LSM context Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
2020-04-07 18:47 ` Kees Cook
2020-04-07 18:47 ` Kees Cook
2020-04-07 0:01 ` [PATCH v16 23/23] AppArmor: Remove the exclusive flag Casey Schaufler
2020-04-07 0:01 ` Casey Schaufler
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