Merge tag 'selinux-pr-20210629' of git://git.kernel.org/pub/scm/linux…

…/kernel/git/pcmoore/selinux

Pull SELinux updates from Paul Moore:

 - The slow_avc_audit() function is now non-blocking so we can remove
   the AVC_NONBLOCKING tricks; this also includes the 'flags' variant of
   avc_has_perm().

 - Use kmemdup() instead of kcalloc()+copy when copying parts of the
   SELinux policydb.

 - The InfiniBand device name is now passed by reference when possible
   in the SELinux code, removing a strncpy().

 - Minor cleanups including: constification of avtab function args,
   removal of useless LSM/XFRM function args, SELinux kdoc fixes, and
   removal of redundant assignments.

* tag 'selinux-pr-20210629' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: kill 'flags' argument in avc_has_perm_flags() and avc_audit()
  selinux: slow_avc_audit has become non-blocking
  selinux: Fix kernel-doc
  selinux: use __GFP_NOWARN with GFP_NOWAIT in the AVC
  lsm_audit,selinux: pass IB device name by reference
  selinux: Remove redundant assignment to rc
  selinux: Corrected comment to match kernel-doc comment
  selinux: delete selinux_xfrm_policy_lookup() useless argument
  selinux: constify some avtab function arguments
  selinux: simplify duplicate_policydb_cond_list() by using kmemdup()

include/linux/lsm_audit.h

@@ -48,13 +48,13 @@ struct lsm_ioctlop_audit {
 };
 
 struct lsm_ibpkey_audit {
-	u64	subnet_prefix;
-	u16	pkey;
+	u64 subnet_prefix;
+	u16 pkey;
 };
 
 struct lsm_ibendport_audit {
-	char	dev_name[IB_DEVICE_NAME_MAX];
-	u8	port;
+	const char *dev_name;
+	u8 port;
 };
 
 /* Auxiliary data to use in generating the audit record. */

include/linux/lsm_hook_defs.h

@@ -358,8 +358,7 @@ LSM_HOOK(int, 0, xfrm_state_alloc_acquire, struct xfrm_state *x,
 	 struct xfrm_sec_ctx *polsec, u32 secid)
 LSM_HOOK(void, LSM_RET_VOID, xfrm_state_free_security, struct xfrm_state *x)
 LSM_HOOK(int, 0, xfrm_state_delete_security, struct xfrm_state *x)
-LSM_HOOK(int, 0, xfrm_policy_lookup, struct xfrm_sec_ctx *ctx, u32 fl_secid,
-	 u8 dir)
+LSM_HOOK(int, 0, xfrm_policy_lookup, struct xfrm_sec_ctx *ctx, u32 fl_secid)
 LSM_HOOK(int, 1, xfrm_state_pol_flow_match, struct xfrm_state *x,
 	 struct xfrm_policy *xp, const struct flowi_common *flic)
 LSM_HOOK(int, 0, xfrm_decode_session, struct sk_buff *skb, u32 *secid,

include/linux/security.h

@@ -1681,7 +1681,7 @@ int security_xfrm_state_alloc_acquire(struct xfrm_state *x,
 				      struct xfrm_sec_ctx *polsec, u32 secid);
 int security_xfrm_state_delete(struct xfrm_state *x);
 void security_xfrm_state_free(struct xfrm_state *x);
-int security_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir);
+int security_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid);
 int security_xfrm_state_pol_flow_match(struct xfrm_state *x,
 				       struct xfrm_policy *xp,
 				       const struct flowi_common *flic);
@@ -1732,7 +1732,7 @@ static inline int security_xfrm_state_delete(struct xfrm_state *x)
 	return 0;
 }
 
-static inline int security_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir)
+static inline int security_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid)
 {
 	return 0;
 }

net/xfrm/xfrm_policy.c

@@ -1902,8 +1902,7 @@ static int xfrm_policy_match(const struct xfrm_policy *pol,
 
 	match = xfrm_selector_match(sel, fl, family);
 	if (match)
-		ret = security_xfrm_policy_lookup(pol->security, fl->flowi_secid,
-						  dir);
+		ret = security_xfrm_policy_lookup(pol->security, fl->flowi_secid);
 	return ret;
 }
 
@@ -2181,8 +2180,7 @@ static struct xfrm_policy *xfrm_sk_policy_lookup(const struct sock *sk, int dir,
 				goto out;
 			}
 			err = security_xfrm_policy_lookup(pol->security,
-						      fl->flowi_secid,
-						      dir);
+						      fl->flowi_secid);
 			if (!err) {
 				if (!xfrm_pol_hold_rcu(pol))
 					goto again;

security/security.c

@@ -2466,9 +2466,9 @@ void security_xfrm_state_free(struct xfrm_state *x)
 	call_void_hook(xfrm_state_free_security, x);
 }
 
-int security_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir)
+int security_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid)
 {
-	return call_int_hook(xfrm_policy_lookup, 0, ctx, fl_secid, dir);
+	return call_int_hook(xfrm_policy_lookup, 0, ctx, fl_secid);
 }
 
 int security_xfrm_state_pol_flow_match(struct xfrm_state *x,

security/selinux/avc.c

@@ -297,26 +297,27 @@ static struct avc_xperms_decision_node
 	struct avc_xperms_decision_node *xpd_node;
 	struct extended_perms_decision *xpd;
 
-	xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep, GFP_NOWAIT);
+	xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep,
+				     GFP_NOWAIT | __GFP_NOWARN);
 	if (!xpd_node)
 		return NULL;
 
 	xpd = &xpd_node->xpd;
 	if (which & XPERMS_ALLOWED) {
 		xpd->allowed = kmem_cache_zalloc(avc_xperms_data_cachep,
-						GFP_NOWAIT);
+						GFP_NOWAIT | __GFP_NOWARN);
 		if (!xpd->allowed)
 			goto error;
 	}
 	if (which & XPERMS_AUDITALLOW) {
 		xpd->auditallow = kmem_cache_zalloc(avc_xperms_data_cachep,
-						GFP_NOWAIT);
+						GFP_NOWAIT | __GFP_NOWARN);
 		if (!xpd->auditallow)
 			goto error;
 	}
 	if (which & XPERMS_DONTAUDIT) {
 		xpd->dontaudit = kmem_cache_zalloc(avc_xperms_data_cachep,
-						GFP_NOWAIT);
+						GFP_NOWAIT | __GFP_NOWARN);
 		if (!xpd->dontaudit)
 			goto error;
 	}
@@ -344,7 +345,7 @@ static struct avc_xperms_node *avc_xperms_alloc(void)
 {
 	struct avc_xperms_node *xp_node;
 
-	xp_node = kmem_cache_zalloc(avc_xperms_cachep, GFP_NOWAIT);
+	xp_node = kmem_cache_zalloc(avc_xperms_cachep, GFP_NOWAIT | __GFP_NOWARN);
 	if (!xp_node)
 		return xp_node;
 	INIT_LIST_HEAD(&xp_node->xpd_head);
@@ -500,7 +501,7 @@ static struct avc_node *avc_alloc_node(struct selinux_avc *avc)
 {
 	struct avc_node *node;
 
-	node = kmem_cache_zalloc(avc_node_cachep, GFP_NOWAIT);
+	node = kmem_cache_zalloc(avc_node_cachep, GFP_NOWAIT | __GFP_NOWARN);
 	if (!node)
 		goto out;
 
@@ -758,7 +759,11 @@ static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
 	}
 }
 
-/* This is the slow part of avc audit with big stack footprint */
+/*
+ * This is the slow part of avc audit with big stack footprint.
+ * Note that it is non-blocking and can be called from under
+ * rcu_read_lock().
+ */
 noinline int slow_avc_audit(struct selinux_state *state,
 			    u32 ssid, u32 tsid, u16 tclass,
 			    u32 requested, u32 audited, u32 denied, int result,
@@ -819,13 +824,13 @@ int __init avc_add_callback(int (*callback)(u32 event), u32 events)
 }
 
 /**
- * avc_update_node Update an AVC entry
+ * avc_update_node - Update an AVC entry
  * @event : Updating event
  * @perms : Permission mask bits
  * @ssid,@tsid,@tclass : identifier of an AVC entry
  * @seqno : sequence number when decision was made
  * @xpd: extended_perms_decision to be added to the node
- * @flags: the AVC_* flags, e.g. AVC_NONBLOCKING, AVC_EXTENDED_PERMS, or 0.
+ * @flags: the AVC_* flags, e.g. AVC_EXTENDED_PERMS, or 0.
  *
  * if a valid AVC entry doesn't exist,this function returns -ENOENT.
  * if kmalloc() called internal returns NULL, this function returns -ENOMEM.
@@ -844,21 +849,6 @@ static int avc_update_node(struct selinux_avc *avc,
 	struct hlist_head *head;
 	spinlock_t *lock;
 
-	/*
-	 * If we are in a non-blocking code path, e.g. VFS RCU walk,
-	 * then we must not add permissions to a cache entry
-	 * because we will not audit the denial.  Otherwise,
-	 * during the subsequent blocking retry (e.g. VFS ref walk), we
-	 * will find the permissions already granted in the cache entry
-	 * and won't audit anything at all, leading to silent denials in
-	 * permissive mode that only appear when in enforcing mode.
-	 *
-	 * See the corresponding handling of MAY_NOT_BLOCK in avc_audit()
-	 * and selinux_inode_permission().
-	 */
-	if (flags & AVC_NONBLOCKING)
-		return 0;
-
 	node = avc_alloc_node(avc);
 	if (!node) {
 		rc = -ENOMEM;
@@ -1119,7 +1109,7 @@ int avc_has_extended_perms(struct selinux_state *state,
  * @tsid: target security identifier
  * @tclass: target security class
  * @requested: requested permissions, interpreted based on @tclass
- * @flags:  AVC_STRICT, AVC_NONBLOCKING, or 0
+ * @flags:  AVC_STRICT or 0
  * @avd: access vector decisions
  *
  * Check the AVC to determine whether the @requested permissions are granted
@@ -1190,26 +1180,7 @@ int avc_has_perm(struct selinux_state *state, u32 ssid, u32 tsid, u16 tclass,
 				  &avd);
 
 	rc2 = avc_audit(state, ssid, tsid, tclass, requested, &avd, rc,
-			auditdata, 0);
-	if (rc2)
-		return rc2;
-	return rc;
-}
-
-int avc_has_perm_flags(struct selinux_state *state,
-		       u32 ssid, u32 tsid, u16 tclass, u32 requested,
-		       struct common_audit_data *auditdata,
-		       int flags)
-{
-	struct av_decision avd;
-	int rc, rc2;
-
-	rc = avc_has_perm_noaudit(state, ssid, tsid, tclass, requested,
-				  (flags & MAY_NOT_BLOCK) ? AVC_NONBLOCKING : 0,
-				  &avd);
-
-	rc2 = avc_audit(state, ssid, tsid, tclass, requested, &avd, rc,
-			auditdata, flags);
+			auditdata);
 	if (rc2)
 		return rc2;
 	return rc;

security/selinux/hooks.c

@@ -1676,7 +1676,7 @@ static int cred_has_capability(const struct cred *cred,
 				  sid, sid, sclass, av, 0, &avd);
 	if (!(opts & CAP_OPT_NOAUDIT)) {
 		int rc2 = avc_audit(&selinux_state,
-				    sid, sid, sclass, av, &avd, rc, &ad, 0);
+				    sid, sid, sclass, av, &avd, rc, &ad);
 		if (rc2)
 			return rc2;
 	}
@@ -3153,9 +3153,8 @@ static int selinux_inode_follow_link(struct dentry *dentry, struct inode *inode,
 	if (IS_ERR(isec))
 		return PTR_ERR(isec);
 
-	return avc_has_perm_flags(&selinux_state,
-				  sid, isec->sid, isec->sclass, FILE__READ, &ad,
-				  rcu ? MAY_NOT_BLOCK : 0);
+	return avc_has_perm(&selinux_state,
+				  sid, isec->sid, isec->sclass, FILE__READ, &ad);
 }
 
 static noinline int audit_inode_permission(struct inode *inode,
@@ -3164,17 +3163,13 @@ static noinline int audit_inode_permission(struct inode *inode,
 {
 	struct common_audit_data ad;
 	struct inode_security_struct *isec = selinux_inode(inode);
-	int rc;
 
 	ad.type = LSM_AUDIT_DATA_INODE;
 	ad.u.inode = inode;
 
-	rc = slow_avc_audit(&selinux_state,
+	return slow_avc_audit(&selinux_state,
 			    current_sid(), isec->sid, isec->sclass, perms,
 			    audited, denied, result, &ad);
-	if (rc)
-		return rc;
-	return 0;
 }
 
 static int selinux_inode_permission(struct inode *inode, int mask)
@@ -3209,19 +3204,14 @@ static int selinux_inode_permission(struct inode *inode, int mask)
 		return PTR_ERR(isec);
 
 	rc = avc_has_perm_noaudit(&selinux_state,
-				  sid, isec->sid, isec->sclass, perms,
-				  no_block ? AVC_NONBLOCKING : 0,
+				  sid, isec->sid, isec->sclass, perms, 0,
 				  &avd);
 	audited = avc_audit_required(perms, &avd, rc,
 				     from_access ? FILE__AUDIT_ACCESS : 0,
 				     &denied);
 	if (likely(!audited))
 		return rc;
 
-	/* fall back to ref-walk if we have to generate audit */
-	if (no_block)
-		return -ECHILD;
-
 	rc2 = audit_inode_permission(inode, perms, audited, denied, rc);
 	if (rc2)
 		return rc2;
@@ -6850,7 +6840,7 @@ static int selinux_ib_endport_manage_subnet(void *ib_sec, const char *dev_name,
 		return err;
 
 	ad.type = LSM_AUDIT_DATA_IBENDPORT;
-	strncpy(ibendport.dev_name, dev_name, sizeof(ibendport.dev_name));
+	ibendport.dev_name = dev_name;
 	ibendport.port = port_num;
 	ad.u.ibendport = &ibendport;
 	return avc_has_perm(&selinux_state,

security/selinux/include/avc.h

@@ -111,7 +111,6 @@ int slow_avc_audit(struct selinux_state *state,
  * @avd: access vector decisions
  * @result: result from avc_has_perm_noaudit
  * @a:  auxiliary audit data
- * @flags: VFS walk flags
  *
  * Audit the granting or denial of permissions in accordance
  * with the policy.  This function is typically called by
@@ -127,24 +126,19 @@ static inline int avc_audit(struct selinux_state *state,
 			    u16 tclass, u32 requested,
 			    struct av_decision *avd,
 			    int result,
-			    struct common_audit_data *a,
-			    int flags)
+			    struct common_audit_data *a)
 {
 	u32 audited, denied;
 	audited = avc_audit_required(requested, avd, result, 0, &denied);
 	if (likely(!audited))
 		return 0;
-	/* fall back to ref-walk if we have to generate audit */
-	if (flags & MAY_NOT_BLOCK)
-		return -ECHILD;
 	return slow_avc_audit(state, ssid, tsid, tclass,
 			      requested, audited, denied, result,
 			      a);
 }
 
 #define AVC_STRICT 1 /* Ignore permissive mode. */
 #define AVC_EXTENDED_PERMS 2	/* update extended permissions */
-#define AVC_NONBLOCKING    4	/* non blocking */
 int avc_has_perm_noaudit(struct selinux_state *state,
 			 u32 ssid, u32 tsid,
 			 u16 tclass, u32 requested,
@@ -155,11 +149,6 @@ int avc_has_perm(struct selinux_state *state,
 		 u32 ssid, u32 tsid,
 		 u16 tclass, u32 requested,
 		 struct common_audit_data *auditdata);
-int avc_has_perm_flags(struct selinux_state *state,
-		       u32 ssid, u32 tsid,
-		       u16 tclass, u32 requested,
-		       struct common_audit_data *auditdata,
-		       int flags);
 
 int avc_has_extended_perms(struct selinux_state *state,
 			   u32 ssid, u32 tsid, u16 tclass, u32 requested,

security/selinux/include/xfrm.h

@@ -23,7 +23,7 @@ int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
 				     struct xfrm_sec_ctx *polsec, u32 secid);
 void selinux_xfrm_state_free(struct xfrm_state *x);
 int selinux_xfrm_state_delete(struct xfrm_state *x);
-int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir);
+int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid);
 int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x,
 				      struct xfrm_policy *xp,
 				      const struct flowi_common *flic);