[PATCH -mm 3/4] Audit: start not to use SELinux exported symbols

[Ahmed S. Darwish]

Remove the following exported SELinux interfaces:
selinux_get_inode_sid(inode, sid)
selinux_get_ipc_sid(ipcp, sid) 
selinux_get_task_sid(tsk, sid)
selinux_sid_to_string(sid, ctx, len)

and substitue them with following generic LSM equivalents 
respectively:
security_inode_getsecid(inode, secid)
security_ipc_getsecid*(ipcp, secid)
security_task_getsecid(tsk, secid)
security_sid_to_secctx(sid, ctx, len)

Let the security_task_getsecid(tsk, secid) LSM hook set
the secid to 0 by default if CONFIG_SECURITY is not defined 
or if the hook is set to NULL (dummy). This is done to
notify the caller that no valid secid exists.

Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
Signed-off-by: Ahmed S. Darwish <darwish.07@xxxxxxxxx>
---

 include/linux/security.h |    5 ++++-
 kernel/audit.c           |   14 +++++++-------
 kernel/auditfilter.c     |    5 +++--
 kernel/auditsc.c         |   37 ++++++++++++++++++-------------------
 security/dummy.c         |    4 +++-
 6 files changed, 36 insertions(+), 32 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index a7fb136..35c98f0 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -621,6 +621,7 @@ struct request_sock;
  * @task_getsecid:
  *	Retrieve the security identifier of the process @p.
  *	@p contains the task_struct for the process and place is into @secid.
+ *      In case of failure, @secid will be set to zero
  * @task_setgroups:
  *	Check permission before setting the supplementary group set of the
  *	current process.
@@ -2115,7 +2116,9 @@ static inline int security_task_getsid (struct task_struct *p)
 }
 
 static inline void security_task_getsecid (struct task_struct *p, u32 *secid)
-{ }
+{ 
+	*secid = 0;
+}
 
 static inline int security_task_setgroups (struct group_info *group_info)
 {
diff --git a/security/dummy.c b/security/dummy.c
index c2f4c52..56b007e 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -545,7 +545,9 @@ static int dummy_task_getsid (struct task_struct *p)
 }
 
 static void dummy_task_getsecid (struct task_struct *p, u32 *secid)
-{ }
+{
+	*secid = 0;
+}
 
 static int dummy_task_setgroups (struct group_info *group_info)
 {
diff --git a/kernel/audit.c b/kernel/audit.c
index 8316a88..2bd4124 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -259,13 +259,13 @@ static int audit_log_config_change(char *function_name, int new, int old,
 		char *ctx = NULL;
 		u32 len;
 
-		rc = selinux_sid_to_string(sid, &ctx, &len);
+		rc = security_secid_to_secctx(sid, &ctx, &len);
 		if (rc) {
 			audit_log_format(ab, " sid=%u", sid);
 			allow_changes = 0; /* Something weird, deny request */
 		} else {
 			audit_log_format(ab, " subj=%s", ctx);
-			kfree(ctx);
+			security_release_secctx(ctx, len);
 		}
 	}
 	audit_log_format(ab, " res=%d", allow_changes);
@@ -543,12 +543,12 @@ static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type,
 	audit_log_format(*ab, "user pid=%d uid=%u auid=%u",
 			 pid, uid, auid);
 	if (sid) {
-		rc = selinux_sid_to_string(sid, &ctx, &len);
+		rc = security_secid_to_secctx(sid, &ctx, &len);
 		if (rc)
 			audit_log_format(*ab, " ssid=%u", sid);
 		else
 			audit_log_format(*ab, " subj=%s", ctx);
-		kfree(ctx);
+		security_release_secctx(ctx, len);
 	}
 
 	return rc;
@@ -750,18 +750,18 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		break;
 	}
 	case AUDIT_SIGNAL_INFO:
-		err = selinux_sid_to_string(audit_sig_sid, &ctx, &len);
+		err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
 		if (err)
 			return err;
 		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
 		if (!sig_data) {
-			kfree(ctx);
+			security_release_secctx(ctx, len);
 			return -ENOMEM;
 		}
 		sig_data->uid = audit_sig_uid;
 		sig_data->pid = audit_sig_pid;
 		memcpy(sig_data->ctx, ctx, len);
-		kfree(ctx);
+		security_release_secctx(ctx, len);
 		audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
 				0, 0, sig_data, sizeof(*sig_data) + len);
 		kfree(sig_data);
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 2f2914b..894e3bd 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -28,6 +28,7 @@
 #include <linux/netlink.h>
 #include <linux/sched.h>
 #include <linux/inotify.h>
+#include <linux/security.h>
 #include <linux/selinux.h>
 #include "audit.h"
 
@@ -1515,11 +1516,11 @@ static void audit_log_rule_change(uid_t loginuid, u32 sid, char *action,
 	if (sid) {
 		char *ctx = NULL;
 		u32 len;
-		if (selinux_sid_to_string(sid, &ctx, &len))
+		if (security_secid_to_secctx(sid, &ctx, &len))
 			audit_log_format(ab, " ssid=%u", sid);
 		else
 			audit_log_format(ab, " subj=%s", ctx);
-		kfree(ctx);
+		security_release_secctx(ctx, len);
 	}
 	audit_log_format(ab, " op=%s rule key=", action);
 	if (rule->filterkey)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d07fc4a..631c044 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -530,7 +530,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 			   logged upon error */
 			if (f->se_rule) {
 				if (need_sid) {
-					selinux_get_task_sid(tsk, &sid);
+					security_task_getsecid(tsk, &sid);
 					need_sid = 0;
 				}
 				result = selinux_audit_rule_match(sid, f->type,
@@ -885,11 +885,11 @@ void audit_log_task_context(struct audit_buffer *ab)
 	int error;
 	u32 sid;
 
-	selinux_get_task_sid(current, &sid);
+	security_task_getsecid(current, &sid);
 	if (!sid)
 		return;
 
-	error = selinux_sid_to_string(sid, &ctx, &len);
+	error = security_secid_to_secctx(sid, &ctx, &len);
 	if (error) {
 		if (error != -EINVAL)
 			goto error_path;
@@ -897,7 +897,7 @@ void audit_log_task_context(struct audit_buffer *ab)
 	}
 
 	audit_log_format(ab, " subj=%s", ctx);
-	kfree(ctx);
+	security_release_secctx(ctx, len);
 	return;
 
 error_path:
@@ -951,7 +951,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 
 	audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid, auid,
 			 uid, sessionid);
-	if (selinux_sid_to_string(sid, &s, &len)) {
+	if (security_secid_to_secctx(sid, &s, &len)) {
 		audit_log_format(ab, " obj=(none)");
 		rc = 1;
 	} else
@@ -1268,14 +1268,14 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
 			if (axi->osid != 0) {
 				char *ctx = NULL;
 				u32 len;
-				if (selinux_sid_to_string(
+				if (security_secid_to_secctx(
 						axi->osid, &ctx, &len)) {
 					audit_log_format(ab, " osid=%u",
 							axi->osid);
 					call_panic = 1;
 				} else
 					audit_log_format(ab, " obj=%s", ctx);
-				kfree(ctx);
+				security_release_secctx(ctx, len);
 			}
 			break; }
 
@@ -1389,13 +1389,13 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
 		if (n->osid != 0) {
 			char *ctx = NULL;
 			u32 len;
-			if (selinux_sid_to_string(
+			if (security_secid_to_secctx(
 				n->osid, &ctx, &len)) {
 				audit_log_format(ab, " osid=%u", n->osid);
 				call_panic = 2;
 			} else
 				audit_log_format(ab, " obj=%s", ctx);
-			kfree(ctx);
+			security_release_secctx(ctx, len);
 		}
 
 		audit_log_end(ab);
@@ -1772,7 +1772,7 @@ static void audit_copy_inode(struct audit_names *name, const struct inode *inode
 	name->uid   = inode->i_uid;
 	name->gid   = inode->i_gid;
 	name->rdev  = inode->i_rdev;
-	selinux_get_inode_sid(inode, &name->osid);
+	security_inode_getsecid(inode, &name->osid);
 }
 
 /**
@@ -2187,8 +2187,7 @@ int __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 	ax->uid = ipcp->uid;
 	ax->gid = ipcp->gid;
 	ax->mode = ipcp->mode;
-	selinux_get_ipc_sid(ipcp, &ax->osid);
-
+	security_ipc_getsecid(ipcp, &ax->osid);
 	ax->d.type = AUDIT_IPC;
 	ax->d.next = context->aux;
 	context->aux = (void *)ax;
@@ -2340,7 +2339,7 @@ void __audit_ptrace(struct task_struct *t)
 	context->target_auid = audit_get_loginuid(t);
 	context->target_uid = t->uid;
 	context->target_sessionid = audit_get_sessionid(t);
-	selinux_get_task_sid(t, &context->target_sid);
+	security_task_getsecid(t, &context->target_sid);
 	memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
 }
 
@@ -2368,7 +2367,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
 				audit_sig_uid = tsk->loginuid;
 			else
 				audit_sig_uid = tsk->uid;
-			selinux_get_task_sid(tsk, &audit_sig_sid);
+			security_task_getsecid(tsk, &audit_sig_sid);
 		}
 		if (!audit_signals || audit_dummy_context())
 			return 0;
@@ -2381,7 +2380,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
 		ctx->target_auid = audit_get_loginuid(t);
 		ctx->target_uid = t->uid;
 		ctx->target_sessionid = audit_get_sessionid(t);
-		selinux_get_task_sid(t, &ctx->target_sid);
+		security_task_getsecid(t, &ctx->target_sid);
 		memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
 		return 0;
 	}
@@ -2402,7 +2401,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
 	axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
 	axp->target_uid[axp->pid_count] = t->uid;
 	axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
-	selinux_get_task_sid(t, &axp->target_sid[axp->pid_count]);
+	security_task_getsecid(t, &axp->target_sid[axp->pid_count]);
 	memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
 	axp->pid_count++;
 
@@ -2432,16 +2431,16 @@ void audit_core_dumps(long signr)
 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_ANOM_ABEND);
 	audit_log_format(ab, "auid=%u uid=%u gid=%u ses=%u",
 			auid, current->uid, current->gid, sessionid);
-	selinux_get_task_sid(current, &sid);
+	security_task_getsecid(current, &sid);
 	if (sid) {
 		char *ctx = NULL;
 		u32 len;
 
-		if (selinux_sid_to_string(sid, &ctx, &len))
+		if (security_secid_to_secctx(sid, &ctx, &len))
 			audit_log_format(ab, " ssid=%u", sid);
 		else
 			audit_log_format(ab, " subj=%s", ctx);
-		kfree(ctx);
+		security_release_secctx(ctx, len);
 	}
 	audit_log_format(ab, " pid=%d comm=", current->pid);
 	audit_log_untrustedstring(ab, current->comm);


-- 

"Better to light a candle, than curse the darkness"

Ahmed S. Darwish
Homepage: http://darwish.07.googlepages.com
Blog: http://darwish-07.blogspot.com

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