[PATCH v4 5/5] SELinux: Support SELinux determination of side-channel

From: Casey Schaufler
Date: Fri Aug 24 2018 - 18:41:47 EST


SELinux considers tasks to be side-channel safe if they
have FILE__READ access.

Signed-off-by: Casey Schaufler <casey.schaufler@xxxxxxxxx>
---
security/selinux/hooks.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index a8bf324130f5..992f2402edaa 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4219,6 +4219,14 @@ static void selinux_task_to_inode(struct task_struct *p,
spin_unlock(&isec->lock);
}

+static int selinux_task_safe_sidechannel(struct task_struct *p)
+{
+ struct av_decision avd;
+
+ return avc_has_perm_noaudit(&selinux_state, current_sid(), task_sid(p),
+ SECCLASS_FILE, FILE__READ, 0, &avd);
+}
+
/* Returns error only if unable to parse addresses */
static int selinux_parse_skb_ipv4(struct sk_buff *skb,
struct common_audit_data *ad, u8 *proto)
@@ -7002,6 +7010,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(task_movememory, selinux_task_movememory),
LSM_HOOK_INIT(task_kill, selinux_task_kill),
LSM_HOOK_INIT(task_to_inode, selinux_task_to_inode),
+ LSM_HOOK_INIT(task_safe_sidechannel, selinux_task_safe_sidechannel),

LSM_HOOK_INIT(ipc_permission, selinux_ipc_permission),
LSM_HOOK_INIT(ipc_getsecid, selinux_ipc_getsecid),
--
2.17.1