From: Casey Schaufler <casey.schaufler@intel.com>
To: kernel-hardening@lists.openwall.com,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov,
casey.schaufler@intel.com, dave.hansen@intel.com,
deneen.t.dock@intel.com, kristen@linux.intel.com,
arjan@linux.intel.com
Subject: [PATCH RFC v2 4/5] Smack: Support determination of side-channel vulnerability
Date: Fri, 17 Aug 2018 15:16:23 -0700 [thread overview]
Message-ID: <20180817221624.10232-5-casey.schaufler@intel.com> (raw)
In-Reply-To: <20180817221624.10232-1-casey.schaufler@intel.com>
Smack considers its private task data safe if the current task
has read access to the passed task.
Signed-off-by: Casey Schaufler <casey.schaufler@intel.com>
---
security/smack/smack_lsm.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 91750205a5de..85dc053e610c 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2299,6 +2299,23 @@ static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
isp->smk_inode = skp;
}
+/**
+ * smack_task_safe_sidechannel - Are the task and current sidechannel safe?
+ * @p: task to check on
+ *
+ * A crude value for sidechannel safety is that the current task is
+ * already allowed to read from the other.
+ *
+ * Returns 0 if the tasks are sidechannel safe, -EACCES otherwise.
+ */
+static int smack_task_safe_sidechannel(struct task_struct *p)
+{
+ struct smack_known *skp = smk_of_task_struct(p);
+ struct smack_known *ckp = smk_of_task_struct(current);
+
+ return smk_access(ckp, skp, MAY_READ, NULL);
+}
+
/*
* Socket hooks.
*/
@@ -4718,6 +4735,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(task_movememory, smack_task_movememory),
LSM_HOOK_INIT(task_kill, smack_task_kill),
LSM_HOOK_INIT(task_to_inode, smack_task_to_inode),
+ LSM_HOOK_INIT(task_safe_sidechannel, smack_task_safe_sidechannel),
LSM_HOOK_INIT(ipc_permission, smack_ipc_permission),
LSM_HOOK_INIT(ipc_getsecid, smack_ipc_getsecid),
--
2.17.1
next prev parent reply other threads:[~2018-08-17 22:16 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-17 22:16 [PATCH RFC v2 0/5] LSM: Add and use a hook for side-channel safety checks Casey Schaufler
2018-08-17 22:16 ` [PATCH RFC v2 1/5] LSM: Introduce a hook for side-channel danger Casey Schaufler
2018-08-17 22:16 ` [PATCH RFC v2 2/5] X86: Support LSM determination of side-channel vulnerability Casey Schaufler
2018-08-17 23:55 ` Jann Horn
2018-08-20 14:45 ` Schaufler, Casey
2018-08-21 10:20 ` Jann Horn
2018-08-21 16:37 ` Schaufler, Casey
2018-08-21 17:45 ` Jann Horn
2018-08-17 22:16 ` [PATCH RFC v2 3/5] LSM: Security module checking for side-channel dangers Casey Schaufler
2018-08-17 23:52 ` Jann Horn
2018-08-20 15:31 ` Schaufler, Casey
2018-08-17 22:16 ` Casey Schaufler [this message]
2018-08-17 22:16 ` [PATCH RFC v2 5/5] SELinux: Support SELinux determination of side-channel vulnerability Casey Schaufler
2018-08-20 16:02 ` Stephen Smalley
2018-08-20 16:59 ` Schaufler, Casey
2018-08-20 17:43 ` Stephen Smalley
2018-08-20 19:30 ` Schaufler, Casey
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