Smack<->Audit integration

Hi all,

This is the second step of integrating Audit with Smack.

The AUDIT_SUBJ_USER and AUDIT_OBJ_USER SELinux flags are recycled for Smack to avoid `auditd' userspace modifications. Smack only needs auditing on subject/object bases, so those flags were enough.

Patch below setups the new Audit LSM hooks and add a secid field in smack inode and ipc security structures. The secid field was needed cause it's the main Audit way of distinguishing kernel objects to be audited from the remaining ones.

Possibly the last steps would be to:
1- report smack access grants and denials through Audit (like AVC) 2- Letting Audit send an OBJ_USER event in case of a process that
recieved a signal without affecting SELinux.

Thank you for your reviews.

Signed-off-by Ahmed S. Darwish <[email protected]>

---

 smack.h     |    9 ++
 smack_lsm.c |  211

+++++++++++++++++++++++++++++++++++++++++++++++++++++-----

 2 files changed, 200 insertions(+), 17 deletions(-)

Patch is generated over James security/next branch cause it's the only tree that currently has the Audit hooks merged:

security/smack/smack.h +0 -0

 };
 
 #define	SMK_INODE_INSTANT	0x01	/* inode is instantiated */

security/smack/smack_lsm.c +4 -0

index afa7967..5b5e1fd 100644
@@ -6,6 +6,9 @@
  *  Author:
  *	Casey Schaufler <[email protected]>
  *
+ *  Audit integration by:
+ *	Ahmed S. Darwish <[email protected]>
+ *
  *  Copyright (C) 2007 Casey Schaufler <[email protected]>
  *
  *	This program is free software; you can redistribute it and/or modify

@@ -24,6 +27,7 @@
 #include <linux/udp.h>
 #include <linux/mutex.h>
 #include <linux/pipe_fs_i.h>
+#include <linux/audit.h>
 #include <net/netlabel.h>
 #include <net/cipso_ipv4.h>
 

security/smack/smack_lsm.c +1 -0

+
 	return;
 }

@@ -759,6 +766,17 @@ static int smack_inode_listsecurity(struct inode *inode,
 char *buffer,
 	return -EINVAL;
 }

security/smack/smack_lsm.c +2 -0

+}
+
 /*
  * File Hooks

*/

security/smack/smack_lsm.c +1 -0

@@ -1344,6 +1362,7 @@ static int smack_inode_setsecurity(struct inode *inode,
 const char *name,
 				   const void *value, size_t size, int flags)
 {
 	char *sp;
+	struct smack_known *skp;
 	struct inode_smack *nsp = inode->i_security;
 	struct socket_smack *ssp;

security/smack/smack_lsm.c +0 -2

 	struct socket *sock;

@@ -1352,12 +1371,14 @@ static int smack_inode_setsecurity(struct inode
 *inode, const char *name,
 	if (value == NULL || size > SMK_LABELLEN)
 		return -EACCES;
 
-	sp = smk_import(value, size);
-	if (sp == NULL)

security/smack/smack_lsm.c +2 -1

 	/*

@@ -1471,9 +1492,16 @@ static char *smack_of_shm(struct shmid_kernel *shp)
  */
 static int smack_shm_alloc_security(struct shmid_kernel *shp)
 {
-	struct kern_ipc_perm *isp = &shp->shm_perm;
+	struct ipc_smack *isp;
+	struct kern_ipc_perm *ipcp = &shp->shm_perm;
 

security/smack/smack_lsm.c +3 -1

 /**

@@ -1579,9 +1607,16 @@ static char *smack_of_sem(struct sem_array *sma)
  */
 static int smack_sem_alloc_security(struct sem_array *sma)
 {
-	struct kern_ipc_perm *isp = &sma->sem_perm;
+	struct ipc_smack *isp;
+	struct kern_ipc_perm *ipcp = &sma->sem_perm;
+

security/smack/smack_lsm.c +2 -1

 /**

@@ -1682,9 +1717,16 @@ static int smack_sem_semop(struct sem_array *sma,
 struct sembuf *sops,
  */
 static int smack_msg_queue_alloc_security(struct msg_queue *msq)
 {
-	struct kern_ipc_perm *kisp = &msq->q_perm;
+	struct ipc_smack *isp;
+	struct kern_ipc_perm *ipcp = &msq->q_perm;
 

security/smack/smack_lsm.c +1 -2

 /**

@@ -1800,18 +1842,30 @@ static int smack_msg_queue_msgrcv(struct msg_queue
 *msq, struct msg_msg *msg,
 
 /**
  * smack_ipc_permission - Smack access for ipc_permission()
- * @ipp: the object permissions
+ * @ipcp: the object permissions
  * @flag: access requested
  *
  * Returns 0 if current has read and write access, error code otherwise
  */
-static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)

security/smack/smack_lsm.c +0 -0

 	isp->smk_flags |= SMK_INODE_INSTANT;
 

unlockandout:

security/smack/smack_lsm.c +68 -0

@@ -2391,6 +2446,116 @@ static int smack_key_permission(key_ref_t key_ref,
 #endif /* CONFIG_KEYS */
 
 /*
+ * Smack Audit hooks
+ *
+ * Audit requires an internal representation of each Smack specific
+ * rule which works as a glue between the audit hooks. Since smack_known
+ * repository entries are added but never deleted, we'll use the
+ * smack_known entry related to the given audit rule as the needed
+ * smack representation.
+ *
+ * This will also save us from searching the smack labels repository
+ * each time the audit_rule_match hook get called.
+ */
+#ifdef CONFIG_AUDIT
+
+/**
+ * smack_audit_rule_init - Initialize a smack audit rule
+ * @field: Message flags given from user-space (audit.h)
+ * @op: Required operation (Only equality testing is allowed)
+ * @rulestr: Given user-space rule
+ * @vrule: Where we'll save our own audit rule representation
+ *
+ * The label to be audited (rulestr) is created if necessay
+ */
+static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void
 **vrule)
+{
+	struct smack_known **smk_rule = (struct smack_known **)vrule;
+	*smk_rule = NULL;
+
+	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
+		return -EINVAL;
+
+	if (op != AUDIT_EQUAL && op != AUDIT_NOT_EQUAL)
+		return -EINVAL;
+
+	*smk_rule = smk_import_entry(rulestr, 0);
+
+	return 0;
+}
+
+/**
+ * smack_audit_rule_known - Distinguish smack audit rules from others
+ * @krule: rule of interest, in internal kernel representation format
+ *
+ * This is used to filter rules related to Smack from other saved
+ * Audit rules. If it's proved that this rule belongs to us, the
+ * audit_rule_match hook will be used to check a specific kernel
+ * object against its smack audit rule.
+ */
+static int smack_audit_rule_known(struct audit_krule *krule)
+{
+	struct audit_field *f;
+	int i;
+
+	for (i = 0; i < krule->field_count; i++) {
+		f = &krule->fields[i];
+
+		if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
+			return 1;
+	}
+
+	return 0;
+}
+
+/**
+ * smack_audit_rule_match - Audit given secid identified object ?
+ * @secid: Security id to test
+ * @field: Message flags given from user-space
+ * @op: Required operation (only equality is allowed)
+ * @vrule: Smack audit rule that will be checked against the secid object

security/smack/smack_lsm.c +18 -0

+
+	return 0;
+}
+
+/**
+ * smack_audit_rule_free - free internal audit rule representation
+ * @vrule: rule to be freed.
+ *
+ * No memory was allocated in audit_rule_init.
+ */
+static void smack_audit_rule_free(void *vrule)
+{
+	/* No-op */
+}
+
+#endif /* CONFIG_AUDIT */
+
+/*
  * smack_secid_to_secctx - return the smack label for a secid
  * @secid: incoming integer

* @secdata: destination

security/smack/smack_lsm.c +12 -0

@@ -2476,6 +2641,7 @@ struct security_operations smack_ops = {
 	.inode_getsecurity = 		smack_inode_getsecurity,
 	.inode_setsecurity = 		smack_inode_setsecurity,
 	.inode_listsecurity = 		smack_inode_listsecurity,
+	.inode_getsecid =		smack_inode_getsecid,
 
 	.file_permission = 		smack_file_permission,
 	.file_alloc_security = 		smack_file_alloc_security,

@@ -2506,6 +2672,7 @@ struct security_operations smack_ops = {
 	.task_to_inode = 		smack_task_to_inode,
 
 	.ipc_permission = 		smack_ipc_permission,
+	.ipc_getsecid =			smack_ipc_getsecid,
 
 	.msg_msg_alloc_security = 	smack_msg_msg_alloc_security,
 	.msg_msg_free_security = 	smack_msg_msg_free_security,

@@ -2550,12 +2717,22 @@ struct security_operations smack_ops = {
 	.sk_free_security = 		smack_sk_free_security,
 	.sock_graft = 			smack_sock_graft,
 	.inet_conn_request = 		smack_inet_conn_request,
+
  /* key management security hooks */
 #ifdef CONFIG_KEYS
 	.key_alloc = 			smack_key_alloc,
 	.key_free = 			smack_key_free,
 	.key_permission = 		smack_key_permission,
 #endif /* CONFIG_KEYS */
+
+ /* Audit hooks */
+#ifdef CONFIG_AUDIT
+	.audit_rule_init =		smack_audit_rule_init,
+	.audit_rule_known =		smack_audit_rule_known,
+	.audit_rule_match =		smack_audit_rule_match,
+	.audit_rule_free =		smack_audit_rule_free,
+#endif /* CONFIG_AUDIT */
+
 	.secid_to_secctx = 		smack_secid_to_secctx,
 	.secctx_to_secid = 		smack_secctx_to_secid,
 	.release_secctx = 		smack_release_secctx,

Regards,

Signature · 5 lines

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

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

--- "Ahmed S. Darwish" <[email protected]> wrote:

security/smack/smack.h struct inode_smack { · line 60

Quoted 10 lines

security/smack/smack.h +1 -0

index c444f48..2c8bb4c 100644
@@ -57,6 +57,15 @@ struct inode_smack {
 	char		*smk_inode;	/* label of the fso */
 	struct mutex	smk_lock;	/* initialization lock */
 	int		smk_flags;	/* smack inode flags */
+	int		secid;		/* security identifier */

No.

Secid's are horrid things and every effort should be made to expunge them from the known universe. Under no circumstances should thier use be expanded. The only reason Smack has them at all is because certain interfaces that in my mind should have known better use them. If you must deal with secids, and for this round of audit I think that's a given, use smack_to_secid(sp->smk_inode) where you need to. If there's a real performance issue apply intelligence to smack_to_secid instead of storing the secid. There ought to be a way to use container_of to do smack_to_secid, but I had trouble with that and moved along without figuring out what I had done wrong.

Quoted 9 lines

security/smack/smack.h +1 -1

@@ -1696,9 +1738,9 @@ static int smack_msg_queue_alloc_security(struct
 msg_queue *msq)
  */
 static void smack_msg_queue_free_security(struct msg_queue *msq)
 {
-	struct kern_ipc_perm *kisp = &msq->q_perm;
+	struct kern_ipc_perm *ipcp = &msq->q_perm;
 

security/smack/smack.h static int smack_msg_queue_alloc_security(struct · line 1745

Quoted 3 lines

security/smack/smack.h +1 -1

-	kisp->security = NULL;
+	kfree(ipcp->security);
 }

Don't you just hate repetative reviewers?

Quoted 11 lines

security/smack/smack.h +11 -0

+
+/**
+ * smack_audit_rule_match - Audit given secid identified object ?
+ * @secid: Security id to test
+ * @field: Message flags given from user-space
+ * @op: Required operation (only equality is allowed)
+ * @vrule: Smack audit rule that will be checked against the secid object
+ * @actx: audit context associated with the check (used for Audit logging)
+ *
+ * This is the core Audit hook. It's used to identify objects like 
+ * syscalls and inodes requested from user-space to be audited from 

security/smack/smack.h

Quoted 6 lines

+ * remaining kernel objects.
+ */

security/smack/smack.h +4 -0

+static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
+				  struct audit_context *actx)
+{
+	struct smack_known *smk_rule = vrule;

        char *smack;

security/smack/smack.h

Quoted 10 lines

security/smack/smack.h +10 -0

+
+	if (!smk_rule) {
+		audit_log(actx, GFP_KERNEL, AUDIT_SELINUX_ERR,
+			  "Smack: missing rule\n");
+		return -ENOENT;
+	}
+
+	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
+		return 0;
+

        smack = smack_from_secid(secid);

security/smack/smack.h

Quoted 4 lines

security/smack/smack.h +4 -0

+	if (op == AUDIT_EQUAL)
+		return (smk_rule->smk_secid == secid);
+	if (op == AUDIT_NOT_EQUAL)
+		return (smk_rule->smk_secid != secid);

if (op == AUDIT_EQUAL)

		return (smk_rule->smk_smack == smack);
	if (op == AUDIT_NOT_EQUAL)
		return (smk_rule->smk_smack == smack);

security/smack/smack.h

Quoted 11 lines

security/smack/smack.h +11 -0

+
+/**
+ * smack_audit_rule_free - free internal audit rule representation
+ * @vrule: rule to be freed.
+ *
+ * No memory was allocated in audit_rule_init.
+ */
+static void smack_audit_rule_free(void *vrule)
+{
+	/* No-op */
+}

Casey Schaufler
[email protected]

...

Quoted 1 line

You've meant using the short-circuit:

	 smk_rule->smk_smack == smack || strnmp(smack, ..., ..)

Right ?

Hi!,

Setup the new Audit hooks for Smack. The AUDIT_SUBJ_USER and AUDIT_OBJ_USER SELinux flags are recycled to avoid `auditd' userspace modifications. Smack only needs auditing on a subject/object bases, so those flags were enough.

Signed-off-by Ahmed S. Darwish <[email protected]>

---

 smack_lsm.c |  153 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 153 insertions(+)

security/smack/smack_lsm.c +1 -0

index afa7967..d471839 100644
@@ -26,6 +26,7 @@
 #include <linux/pipe_fs_i.h>
 #include <net/netlabel.h>
 #include <net/cipso_ipv4.h>
+#include <linux/audit.h>
 
 #include "smack.h"
 

@@ -759,6 +760,17 @@ static int smack_inode_listsecurity(struct inode *inode,
 char *buffer,
 	return -EINVAL;

security/smack/smack_lsm.c +3 -0

+	*secid = smack_to_secid(isp->smk_inode);
+}
+
 /*
  * File Hooks

*/

security/smack/smack_lsm.c +0 -0

@@ -1814,6 +1826,17 @@ static int smack_ipc_permission(struct kern_ipc_perm
 *ipp, short flag)
 	return smk_curacc(isp, may);

security/smack/smack_lsm.c +3 -0

+	*secid = smack_to_secid(smack);
+}
+
 /* module stacking operations */
 

/**

security/smack/smack_lsm.c +8 -0

@@ -2391,6 +2414,124 @@ static int smack_key_permission(key_ref_t key_ref,
 #endif /* CONFIG_KEYS */
 
 /*
+ * Smack Audit hooks
+ *
+ * Audit requires a unique representation of each Smack specific
+ * rule. This unique representation is used to distinguish the
+ * object to be audited from remaining kernel objects and also
+ * works as a glue between the audit hooks.
+ *
+ * Since repository entries are added but never deleted, we'll use

security/smack/smack_lsm.c +67 -0

+ * @rulestr: smack label to be audited
+ * @vrule: pointer to save our own audit rule representation
+ *
+ * Prepare to audit cases where (@field @op @rulestr) is true.
+ * The label to be audited is created if necessay.
+ */
+static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void
 **vrule)
+{
+	char **rule = (char **)vrule;
+	*rule = NULL;
+
+	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
+		return -EINVAL;
+
+	if (op != AUDIT_EQUAL && op != AUDIT_NOT_EQUAL)
+		return -EINVAL;
+
+	*rule = smk_import(rulestr, 0);
+
+	return 0;
+}
+
+/**
+ * smack_audit_rule_known - Distinguish Smack audit rules
+ * @krule: rule of interest, in Audit kernel representation format
+ *
+ * This is used to filter Smack rules from remaining Audit ones.
+ * If it's proved that this rule belongs to us, the
+ * audit_rule_match hook will be called to do the final judgement.
+ */
+static int smack_audit_rule_known(struct audit_krule *krule)
+{
+	struct audit_field *f;
+	int i;
+
+	for (i = 0; i < krule->field_count; i++) {
+		f = &krule->fields[i];
+
+		if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
+			return 1;
+	}
+
+	return 0;
+}
+
+/**
+ * smack_audit_rule_match - Audit given object ?
+ * @secid: security id for identifying the object to test
+ * @field: audit rule flags given from user-space
+ * @op: required testing operator
+ * @vrule: smack internal rule presentation
+ * @actx: audit context associated with the check
+ *
+ * The core Audit hook. It's used to take the decision of
+ * whether to audit or not to audit a given object.
+ */
+static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
+				  struct audit_context *actx)
+{
+	char *smack;
+	char *rule = vrule;
+
+	if (!rule) {
+		audit_log(actx, GFP_KERNEL, AUDIT_SELINUX_ERR,
+			  "Smack: missing rule\n");
+		return -ENOENT;
+	}

security/smack/smack_lsm.c +23 -0

+	 */
+	if (op == AUDIT_EQUAL)
+		return (rule == smack);
+	if (op == AUDIT_NOT_EQUAL)
+		return (rule != smack);
+
+	return 0;
+}
+
+/**
+ * smack_audit_rule_free - free smack rule representation
+ * @vrule: rule to be freed.
+ *
+ * No memory was allocated.
+ */
+static void smack_audit_rule_free(void *vrule)
+{
+	/* No-op */
+}
+
+#endif /* CONFIG_AUDIT */
+
+/*
  * smack_secid_to_secctx - return the smack label for a secid
  * @secid: incoming integer

* @secdata: destination

security/smack/smack_lsm.c +12 -0

@@ -2476,6 +2617,7 @@ struct security_operations smack_ops = {
 	.inode_getsecurity = 		smack_inode_getsecurity,
 	.inode_setsecurity = 		smack_inode_setsecurity,
 	.inode_listsecurity = 		smack_inode_listsecurity,
+	.inode_getsecid =		smack_inode_getsecid,
 
 	.file_permission = 		smack_file_permission,
 	.file_alloc_security = 		smack_file_alloc_security,

@@ -2506,6 +2648,7 @@ struct security_operations smack_ops = {
 	.task_to_inode = 		smack_task_to_inode,
 
 	.ipc_permission = 		smack_ipc_permission,
+	.ipc_getsecid =			smack_ipc_getsecid,
 
 	.msg_msg_alloc_security = 	smack_msg_msg_alloc_security,
 	.msg_msg_free_security = 	smack_msg_msg_free_security,

@@ -2550,12 +2693,22 @@ struct security_operations smack_ops = {
 	.sk_free_security = 		smack_sk_free_security,
 	.sock_graft = 			smack_sock_graft,
 	.inet_conn_request = 		smack_inet_conn_request,
+
  /* key management security hooks */
 #ifdef CONFIG_KEYS
 	.key_alloc = 			smack_key_alloc,
 	.key_free = 			smack_key_free,
 	.key_permission = 		smack_key_permission,
 #endif /* CONFIG_KEYS */
+
+ /* Audit hooks */
+#ifdef CONFIG_AUDIT
+	.audit_rule_init =		smack_audit_rule_init,
+	.audit_rule_known =		smack_audit_rule_known,
+	.audit_rule_match =		smack_audit_rule_match,
+	.audit_rule_free =		smack_audit_rule_free,
+#endif /* CONFIG_AUDIT */
+
 	.secid_to_secctx = 		smack_secid_to_secctx,
 	.secctx_to_secid = 		smack_secctx_to_secid,
 	.release_secctx = 		smack_release_secctx,

Signature · 7 lines

-- 

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

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

Hi!,

Setup the new Audit hooks for Smack. The AUDIT_SUBJ_USER and AUDIT_OBJ_USER SELinux flags are recycled to avoid `auditd' userspace modifications. Smack only needs auditing on a subject/object bases, so those flags were enough.

Signed-off-by Ahmed S. Darwish <[email protected]>

---

 smack_lsm.c |  153 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 153 insertions(+)

security/smack/smack_lsm.c +153 -0

index afa7967..d471839 100644
@@ -26,6 +26,7 @@
 #include <linux/pipe_fs_i.h>
 #include <net/netlabel.h>
 #include <net/cipso_ipv4.h>
+#include <linux/audit.h>
 
 #include "smack.h"
 

@@ -759,6 +760,17 @@ static int smack_inode_listsecurity(struct inode *inode, char *buffer,
 	return -EINVAL;
 }
 
+/**
+ * smack_inode_getsecid - Extract inode's security id
+ * @inode: inode to extract the info from
+ * @secid: where result will be saved
+ */
+static void smack_inode_getsecid(const struct inode *inode, u32 *secid)
+{
+	struct inode_smack *isp = inode->i_security;
+	*secid = smack_to_secid(isp->smk_inode);
+}
+
 /*
  * File Hooks
  */

@@ -1814,6 +1826,17 @@ static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
 	return smk_curacc(isp, may);
 }
 
+/**
+ * smack_ipc_getsecid - Extract ipc object security id
+ * @ipp: the object permissions
+ * @secid: where result will be saved
+ */
+static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
+{
+	char *smack = ipp->security;
+	*secid = smack_to_secid(smack);
+}
+
 /* module stacking operations */
 
 /**

@@ -2391,6 +2414,124 @@ static int smack_key_permission(key_ref_t key_ref,
 #endif /* CONFIG_KEYS */
 
 /*
+ * Smack Audit hooks
+ *
+ * Audit requires a unique representation of each Smack specific
+ * rule. This unique representation is used to distinguish the
+ * object to be audited from remaining kernel objects and also
+ * works as a glue between the audit hooks.
+ *
+ * Since repository entries are added but never deleted, we'll use
+ * the smack_known label address related to the given audit rule as
+ * the needed unique representation. This also better fits the smack
+ * model where nearly everything is a label.
+ */
+#ifdef CONFIG_AUDIT
+
+/**
+ * smack_audit_rule_init - Initialize a smack audit rule
+ * @field: audit rule fields given from user-space (audit.h)
+ * @op: required testing operator (=, !=, >, <, ...)
+ * @rulestr: smack label to be audited
+ * @vrule: pointer to save our own audit rule representation
+ *
+ * Prepare to audit cases where (@field @op @rulestr) is true.
+ * The label to be audited is created if necessay.
+ */
+static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
+{
+	char **rule = (char **)vrule;
+	*rule = NULL;
+
+	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
+		return -EINVAL;
+
+	if (op != AUDIT_EQUAL && op != AUDIT_NOT_EQUAL)
+		return -EINVAL;
+
+	*rule = smk_import(rulestr, 0);
+
+	return 0;
+}
+
+/**
+ * smack_audit_rule_known - Distinguish Smack audit rules
+ * @krule: rule of interest, in Audit kernel representation format
+ *
+ * This is used to filter Smack rules from remaining Audit ones.
+ * If it's proved that this rule belongs to us, the
+ * audit_rule_match hook will be called to do the final judgement.
+ */
+static int smack_audit_rule_known(struct audit_krule *krule)
+{
+	struct audit_field *f;
+	int i;
+
+	for (i = 0; i < krule->field_count; i++) {
+		f = &krule->fields[i];
+
+		if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
+			return 1;
+	}
+
+	return 0;
+}
+
+/**
+ * smack_audit_rule_match - Audit given object ?
+ * @secid: security id for identifying the object to test
+ * @field: audit rule flags given from user-space
+ * @op: required testing operator
+ * @vrule: smack internal rule presentation
+ * @actx: audit context associated with the check
+ *
+ * The core Audit hook. It's used to take the decision of
+ * whether to audit or not to audit a given object.
+ */
+static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
+				  struct audit_context *actx)
+{
+	char *smack;
+	char *rule = vrule;
+
+	if (!rule) {
+		audit_log(actx, GFP_KERNEL, AUDIT_SELINUX_ERR,
+			  "Smack: missing rule\n");
+		return -ENOENT;
+	}
+
+	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
+		return 0;
+
+	smack = smack_from_secid(secid);
+
+	/*
+	 * No need to do string comparisons since we're sure
+	 * that if a match occurs, both pointers will point
+	 * to the same smack_konwn label.
+	 */
+	if (op == AUDIT_EQUAL)
+		return (rule == smack);
+	if (op == AUDIT_NOT_EQUAL)
+		return (rule != smack);
+
+	return 0;
+}
+
+/**
+ * smack_audit_rule_free - free smack rule representation
+ * @vrule: rule to be freed.
+ *
+ * No memory was allocated.
+ */
+static void smack_audit_rule_free(void *vrule)
+{
+	/* No-op */
+}
+
+#endif /* CONFIG_AUDIT */
+
+/*
  * smack_secid_to_secctx - return the smack label for a secid
  * @secid: incoming integer
  * @secdata: destination

@@ -2476,6 +2617,7 @@ struct security_operations smack_ops = {
 	.inode_getsecurity = 		smack_inode_getsecurity,
 	.inode_setsecurity = 		smack_inode_setsecurity,
 	.inode_listsecurity = 		smack_inode_listsecurity,
+	.inode_getsecid =		smack_inode_getsecid,
 
 	.file_permission = 		smack_file_permission,
 	.file_alloc_security = 		smack_file_alloc_security,

@@ -2506,6 +2648,7 @@ struct security_operations smack_ops = {
 	.task_to_inode = 		smack_task_to_inode,
 
 	.ipc_permission = 		smack_ipc_permission,
+	.ipc_getsecid =			smack_ipc_getsecid,
 
 	.msg_msg_alloc_security = 	smack_msg_msg_alloc_security,
 	.msg_msg_free_security = 	smack_msg_msg_free_security,

@@ -2550,12 +2693,22 @@ struct security_operations smack_ops = {
 	.sk_free_security = 		smack_sk_free_security,
 	.sock_graft = 			smack_sock_graft,
 	.inet_conn_request = 		smack_inet_conn_request,
+
  /* key management security hooks */
 #ifdef CONFIG_KEYS
 	.key_alloc = 			smack_key_alloc,
 	.key_free = 			smack_key_free,
 	.key_permission = 		smack_key_permission,
 #endif /* CONFIG_KEYS */
+
+ /* Audit hooks */
+#ifdef CONFIG_AUDIT
+	.audit_rule_init =		smack_audit_rule_init,
+	.audit_rule_known =		smack_audit_rule_known,
+	.audit_rule_match =		smack_audit_rule_match,
+	.audit_rule_free =		smack_audit_rule_free,
+#endif /* CONFIG_AUDIT */
+
 	.secid_to_secctx = 		smack_secid_to_secctx,
 	.secctx_to_secid = 		smack_secctx_to_secid,
 	.release_secctx = 		smack_release_secctx,

Quoted 6 lines · Ahmed S. Darwish

Hi!,

Setup the new Audit hooks for Smack. The AUDIT_SUBJ_USER and AUDIT_OBJ_USER SELinux flags are recycled to avoid `auditd' userspace modifications. Smack only needs auditing on a subject/object bases, so those flags were enough.

Only question I have is whether audit folks are ok with reuse of the flags in this manner, and whether the _USER flag is best suited for this purpose if you are going to reuse an existing flag (since Smack label seems more like a SELinux type than a SELinux user).

Certainly will confuse matters if a user has audit filters on SELinux users in their /etc/audit/audit.rules and then boots a kernel with Smack enabled.

Quoted 9 lines · --- Stephen Smalley

Quoted 6 lines · Ahmed S. Darwish

Hi!,

Setup the new Audit hooks for Smack. The AUDIT_SUBJ_USER and AUDIT_OBJ_USER SELinux flags are recycled to avoid `auditd' userspace modifications. Smack only needs auditing on a subject/object bases, so those flags were enough.

Quoted 4 lines

Only question I have is whether audit folks are ok with reuse of the flags in this manner, and whether the _USER flag is best suited for this purpose if you are going to reuse an existing flag (since Smack label seems more like a SELinux type than a SELinux user).

To-mate-o toe-maht-o.

There really doesn't seem to be any real reason to create a new flag just because the granularity is different. The choice between _USER and _TYPE (and _ROLE for that matter) is arbitrary from a functional point of view. I say that since Smack has users, but not types or roles, _USER makes the most sense.

Quoted 3 lines

Certainly will confuse matters if a user has audit filters on SELinux users in their /etc/audit/audit.rules and then boots a kernel with Smack enabled.

Somehow I doubt that will be their biggest concern.

Quoted 13 lines · Casey Schaufler

Quoted 11 lines · --- Stephen Smalley

Quoted 6 lines · Ahmed S. Darwish

Hi!,

Setup the new Audit hooks for Smack. The AUDIT_SUBJ_USER and AUDIT_OBJ_USER SELinux flags are recycled to avoid `auditd' userspace modifications. Smack only needs auditing on a subject/object bases, so those flags were enough.

Only question I have is whether audit folks are ok with reuse of the flags in this manner, and whether the _USER flag is best suited for this purpose if you are going to reuse an existing flag (since Smack label seems more like a SELinux type than a SELinux user).

Quoted 7 lines

To-mate-o toe-maht-o.

There really doesn't seem to be any real reason to create a new flag just because the granularity is different. The choice between _USER and _TYPE (and _ROLE for that matter) is arbitrary from a functional point of view. I say that since Smack has users, but not types or roles, _USER makes the most sense.

Perhaps I misunderstand, but Smack labels don't represent users (i.e. user identity) in any way, so it seemed like a mismatch to use the _USER flag there. Whereas types in SELinux bear some similarity to Smack labels - simple unstructured names whose meaning is only defined by the policy rules.

Regardless, it seems like the audit maintainers ought to weigh in on the matter.

Quoted 4 lines

Quoted 3 lines

Certainly will confuse matters if a user has audit filters on SELinux users in their /etc/audit/audit.rules and then boots a kernel with Smack enabled.

Somehow I doubt that will be their biggest concern.

Quoted 16 lines · Casey Schaufler

Quoted 9 lines · --- Stephen Smalley

Quoted 6 lines · Ahmed S. Darwish

Hi!,

Setup the new Audit hooks for Smack. The AUDIT_SUBJ_USER and AUDIT_OBJ_USER SELinux flags are recycled to avoid `auditd' userspace modifications. Smack only needs auditing on a subject/object bases, so those flags were enough.

Quoted 4 lines

Only question I have is whether audit folks are ok with reuse of the flags in this manner, and whether the _USER flag is best suited for this purpose if you are going to reuse an existing flag (since Smack label seems more like a SELinux type than a SELinux user).

Quoted 7 lines

To-mate-o toe-maht-o.

There really doesn't seem to be any real reason to create a new flag just because the granularity is different. The choice between _USER and _TYPE (and _ROLE for that matter) is arbitrary from a functional point of view. I say that since Smack has users, but not types or roles, _USER makes the most sense.

Perhaps I misunderstand, but Smack labels don't represent users (i.e. user identity) in any way, so it seemed like a mismatch to use the _USER flag there. Whereas types in SELinux bear some similarity to Smack labels - simple unstructured names whose meaning is only defined by the policy rules.

Regardless, it seems like the audit maintainers ought to weigh in on the matter.

Quoted 7 lines

Perhaps I misunderstand, but Smack labels don't represent users (i.e. user identity) in any way, so it seemed like a mismatch to use the _USER flag there. Whereas types in SELinux bear some similarity to Smack labels - simple unstructured names whose meaning is only defined by the policy rules.

I think Casey meant the common use of Smack where a login program (openssh, bin/login, ..) sets a label for each user that logs in, thus letting each label effectively representing a user.

In a sense, smack labels share a bit of _USER and _TYPE.

Only question I have is whether audit folks are ok with reuse of the flags in this manner