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From: Casey Schaufler <casey@schaufler-ca.com>
To: casey.schaufler@intel.com, paul@paul-moore.com,
	linux-security-module@vger.kernel.org
Cc: casey@schaufler-ca.com, linux-audit@redhat.com,
	jmorris@namei.org, selinux@vger.kernel.org,
	keescook@chromium.org, john.johansen@canonical.com,
	penguin-kernel@i-love.sakura.ne.jp,
	stephen.smalley.work@gmail.com, linux-kernel@vger.kernel.org
Subject: [PATCH v38 27/39] binder: Pass LSM identifier for confirmation
Date: Tue, 27 Sep 2022 12:54:09 -0700	[thread overview]
Message-ID: <20220927195421.14713-28-casey@schaufler-ca.com> (raw)
In-Reply-To: <20220927195421.14713-1-casey@schaufler-ca.com>

Send an identifier for the security module interface_lsm
along with the security context. This allows the receiver
to verify that the receiver and the sender agree on which
security module's context is being used. If they don't
agree the message is rejected.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 drivers/android/binder.c          | 21 +++++++++++++++++++++
 drivers/android/binder_internal.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 5cfdaec0f9b5..ff8f35b9bd1b 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3222,6 +3222,7 @@ static void binder_transaction(struct binder_proc *proc,
 				    ALIGN(extra_buffers_size, sizeof(void *)) -
 				    ALIGN(lsmctx.len, sizeof(u64));
 
+		t->security_interface = lsm_task_ilsm(current);
 		t->security_ctx = (uintptr_t)t->buffer->user_data + buf_offset;
 		err = binder_alloc_copy_to_buffer(&target_proc->alloc,
 						  t->buffer, buf_offset,
@@ -4667,6 +4668,26 @@ static int binder_thread_read(struct binder_proc *proc,
 
 		tr.secctx = t->security_ctx;
 		if (t->security_ctx) {
+			int to_ilsm = lsm_task_ilsm(current);
+			int from_ilsm = t->security_interface;
+
+			if (to_ilsm == LSMBLOB_INVALID)
+				to_ilsm = 0;
+			if (from_ilsm == LSMBLOB_INVALID)
+				from_ilsm = 0;
+			/*
+			 * The sender provided a security context from
+			 * a different security module than the one this
+			 * process wants to report if these don't match.
+			 */
+			if (from_ilsm != to_ilsm) {
+				if (t_from)
+					binder_thread_dec_tmpref(t_from);
+
+				binder_cleanup_transaction(t, "security context mismatch",
+							   BR_FAILED_REPLY);
+				return -EINVAL;
+			}
 			cmd = BR_TRANSACTION_SEC_CTX;
 			trsize = sizeof(tr);
 		}
diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h
index abe19d88c6ec..152d0b55e050 100644
--- a/drivers/android/binder_internal.h
+++ b/drivers/android/binder_internal.h
@@ -528,6 +528,7 @@ struct binder_transaction {
 	long    saved_priority;
 	kuid_t  sender_euid;
 	struct list_head fd_fixups;
+	int	security_interface;
 	binder_uintptr_t security_ctx;
 	/**
 	 * @lock:  protects @from, @to_proc, and @to_thread
-- 
2.37.3


  parent reply	other threads:[~2022-09-27 20:10 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20220927195421.14713-1-casey.ref@schaufler-ca.com>
2022-09-27 19:53 ` [PATCH v38 00/39] LSM: Module stacking for AppArmor Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 01/39] LSM: Identify modules by more than name Casey Schaufler
2022-10-12 21:14     ` Mickaël Salaün
2023-03-03 15:17     ` Georgia Garcia
2023-03-03 16:52       ` Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 02/39] LSM: Add an LSM identifier for external use Casey Schaufler
2022-10-12 21:14     ` Mickaël Salaün
2022-10-20 22:47       ` Casey Schaufler
2023-03-03 17:14     ` Georgia Garcia
2022-09-27 19:53   ` [PATCH v38 03/39] LSM: Identify the process attributes for each module Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 04/39] LSM: Maintain a table of LSM attribute data Casey Schaufler
2022-10-13 10:04     ` Tetsuo Handa
2022-10-20 23:42       ` Casey Schaufler
2022-10-23  7:27         ` Tetsuo Handa
2022-10-23 10:10           ` Tetsuo Handa
2022-10-23 17:20             ` Casey Schaufler
2022-10-23 17:13           ` Casey Schaufler
2022-10-24 15:13             ` Tetsuo Handa
2022-10-24 16:37               ` Casey Schaufler
2022-10-25  9:59                 ` Tetsuo Handa
2022-09-27 19:53   ` [PATCH v38 05/39] proc: Use lsmids instead of lsm names for attrs Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 06/39] LSM: lsm_self_attr syscall for LSM self attributes Casey Schaufler
2022-09-28 11:04     ` kernel test robot
2022-10-12 21:16     ` Mickaël Salaün
2022-10-20 15:44     ` Paul Moore
2022-10-20 16:13       ` Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 07/39] integrity: disassociate ima_filter_rule from security_audit_rule Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 08/39] LSM: Infrastructure management of the sock security Casey Schaufler
2022-10-12 21:17     ` Mickaël Salaün
2022-09-27 19:53   ` [PATCH v38 09/39] LSM: Add the lsmblob data structure Casey Schaufler
2022-10-12 21:18     ` Mickaël Salaün
2022-09-27 19:53   ` [PATCH v38 10/39] LSM: provide lsm name and id slot mappings Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 11/39] IMA: avoid label collisions with stacked LSMs Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 12/39] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 13/39] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 14/39] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 15/39] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 16/39] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2022-09-27 19:53   ` [PATCH v38 17/39] LSM: Use lsmblob in security_current_getsecid Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 18/39] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 19/39] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 20/39] LSM: Specify which LSM to display Casey Schaufler
2022-10-12 21:19     ` Mickaël Salaün
2022-09-27 19:54   ` [PATCH v38 21/39] LSM: Ensure the correct LSM context releaser Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 22/39] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 23/39] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 24/39] Use lsmcontext in security_dentry_init_security Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 25/39] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 26/39] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2022-09-27 19:54   ` Casey Schaufler [this message]
2022-09-27 19:54   ` [PATCH v38 28/39] LSM: security_secid_to_secctx module selection Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 29/39] Audit: Keep multiple LSM data in audit_names Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 30/39] Audit: Create audit_stamp structure Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 31/39] LSM: Add a function to report multiple LSMs Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 32/39] Audit: Allow multiple records in an audit_buffer Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 33/39] Audit: Add record for multiple task security contexts Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 34/39] audit: multiple subject lsm values for netlabel Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 35/39] Audit: Add record for multiple object contexts Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 36/39] netlabel: Use a struct lsmblob in audit data Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 37/39] LSM: Removed scaffolding function lsmcontext_init Casey Schaufler
2022-09-27 19:54   ` [PATCH v38 38/39] AppArmor: Remove the exclusive flag Casey Schaufler
2022-09-27 20:31   ` [PATCH v38 39/39] LSM: Create lsm_module_list system call Casey Schaufler
2022-09-28 14:27     ` kernel test robot
2022-10-12 21:19     ` Mickaël Salaün
2022-10-20 20:28       ` Casey Schaufler
2022-10-12 22:04     ` Kees Cook
2022-10-25  0:39       ` Casey Schaufler

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