Merge tag 'audit-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit

Pull audit updates from Paul Moore:
 "Add some additional audit logging to capture the openat2() syscall
  open_how struct info.

  Previous variations of the open()/openat() syscalls allowed audit
  admins to inspect the syscall args to get the information contained in
  the new open_how struct used in openat2()"

* tag 'audit-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
  audit: return early if the filter rule has a lower priority
  audit: add OPENAT2 record to list "how" info
  audit: add support for the openat2 syscall
  audit: replace magic audit syscall class numbers with macros
  lsm_audit: avoid overloading the "key" audit field
  audit: Convert to SPDX identifier
  audit: rename struct node to struct audit_node to prevent future name collisions

3 files changed, 41 insertions, 32 deletions

diff --git a/kernel/audit.h b/kernel/audit.h
index d1161e3b83e2..c4498090a5bd 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -14,6 +14,7 @@
 #include <linux/skbuff.h>
 #include <uapi/linux/mqueue.h>
 #include <linux/tty.h>
+#include <uapi/linux/openat2.h> // struct open_how
 
 /* AUDIT_NAMES is the number of slots we reserve in the audit_context
  * for saving names from getname().  If we get more names we will allocate
@@ -193,6 +194,7 @@ struct audit_context {
 			int			fd;
 			int			flags;
 		} mmap;
+		struct open_how openat2;
 		struct {
 			int			argc;
 		} execve;
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 338c53a961c5..72324afcffef 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -30,7 +30,7 @@ struct audit_chunk {
 	int count;
 	atomic_long_t refs;
 	struct rcu_head head;
-	struct node {
+	struct audit_node {
 		struct list_head list;
 		struct audit_tree *owner;
 		unsigned index;		/* index; upper bit indicates 'will prune' */
@@ -269,7 +269,7 @@ bool audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
 
 /* tagging and untagging inodes with trees */
 
-static struct audit_chunk *find_chunk(struct node *p)
+static struct audit_chunk *find_chunk(struct audit_node *p)
 {
 	int index = p->index & ~(1U<<31);
 	p -= index;
@@ -322,7 +322,7 @@ static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old)
 	list_replace_rcu(&old->hash, &new->hash);
 }
 
-static void remove_chunk_node(struct audit_chunk *chunk, struct node *p)
+static void remove_chunk_node(struct audit_chunk *chunk, struct audit_node *p)
 {
 	struct audit_tree *owner = p->owner;
 
@@ -459,7 +459,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
 {
 	struct fsnotify_mark *mark;
 	struct audit_chunk *chunk, *old;
-	struct node *p;
+	struct audit_node *p;
 	int n;
 
 	mutex_lock(&audit_tree_group->mark_mutex);
@@ -570,11 +570,11 @@ static void prune_tree_chunks(struct audit_tree *victim, bool tagged)
 {
 	spin_lock(&hash_lock);
 	while (!list_empty(&victim->chunks)) {
-		struct node *p;
+		struct audit_node *p;
 		struct audit_chunk *chunk;
 		struct fsnotify_mark *mark;
 
-		p = list_first_entry(&victim->chunks, struct node, list);
+		p = list_first_entry(&victim->chunks, struct audit_node, list);
 		/* have we run out of marked? */
 		if (tagged && !(p->index & (1U<<31)))
 			break;
@@ -616,7 +616,7 @@ static void trim_marked(struct audit_tree *tree)
 	}
 	/* reorder */
 	for (p = tree->chunks.next; p != &tree->chunks; p = q) {
-		struct node *node = list_entry(p, struct node, list);
+		struct audit_node *node = list_entry(p, struct audit_node, list);
 		q = p->next;
 		if (node->index & (1U<<31)) {
 			list_del_init(p);
@@ -684,7 +684,7 @@ void audit_trim_trees(void)
 		struct audit_tree *tree;
 		struct path path;
 		struct vfsmount *root_mnt;
-		struct node *node;
+		struct audit_node *node;
 		int err;
 
 		tree = container_of(cursor.next, struct audit_tree, list);
@@ -840,7 +840,7 @@ int audit_add_tree_rule(struct audit_krule *rule)
 	drop_collected_mounts(mnt);
 
 	if (!err) {
-		struct node *node;
+		struct audit_node *node;
 		spin_lock(&hash_lock);
 		list_for_each_entry(node, &tree->chunks, list)
 			node->index &= ~(1U<<31);
@@ -939,7 +939,7 @@ int audit_tag_tree(char *old, char *new)
 		mutex_unlock(&audit_filter_mutex);
 
 		if (!failed) {
-			struct node *node;
+			struct audit_node *node;
 			spin_lock(&hash_lock);
 			list_for_each_entry(node, &tree->chunks, list)
 				node->index &= ~(1U<<31);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index c131985c3e6d..b517947bfa48 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* auditsc.c -- System-call auditing support
  * Handles all system-call specific auditing features.
  *
@@ -6,20 +7,6 @@
  * Copyright (C) 2005, 2006 IBM Corporation
  * All Rights Reserved.
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
  * Written by Rickard E. (Rik) Faith <faith@redhat.com>
  *
  * Many of the ideas implemented here are from Stephen C. Tweedie,
@@ -76,6 +63,7 @@
 #include <linux/fsnotify_backend.h>
 #include <uapi/linux/limits.h>
 #include <uapi/linux/netfilter/nf_tables.h>
+#include <uapi/linux/openat2.h> // struct open_how
 
 #include "audit.h"
 
@@ -166,7 +154,7 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
 	n = ctx->major;
 
 	switch (audit_classify_syscall(ctx->arch, n)) {
-	case 0:	/* native */
+	case AUDITSC_NATIVE:
 		if ((mask & AUDIT_PERM_WRITE) &&
 		     audit_match_class(AUDIT_CLASS_WRITE, n))
 			return 1;
@@ -177,7 +165,7 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
 		     audit_match_class(AUDIT_CLASS_CHATTR, n))
 			return 1;
 		return 0;
-	case 1: /* 32bit on biarch */
+	case AUDITSC_COMPAT: /* 32bit on biarch */
 		if ((mask & AUDIT_PERM_WRITE) &&
 		     audit_match_class(AUDIT_CLASS_WRITE_32, n))
 			return 1;
@@ -188,14 +176,16 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
 		     audit_match_class(AUDIT_CLASS_CHATTR_32, n))
 			return 1;
 		return 0;
-	case 2: /* open */
+	case AUDITSC_OPEN:
 		return mask & ACC_MODE(ctx->argv[1]);
-	case 3: /* openat */
+	case AUDITSC_OPENAT:
 		return mask & ACC_MODE(ctx->argv[2]);
-	case 4: /* socketcall */
+	case AUDITSC_SOCKETCALL:
 		return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
-	case 5: /* execve */
+	case AUDITSC_EXECVE:
 		return mask & AUDIT_PERM_EXEC;
+	case AUDITSC_OPENAT2:
+		return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
 	default:
 		return 0;
 	}
@@ -480,6 +470,9 @@ static int audit_filter_rules(struct task_struct *tsk,
 	u32 sid;
 	unsigned int sessionid;
 
+	if (ctx && rule->prio <= ctx->prio)
+		return 0;
+
 	cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
 
 	for (i = 0; i < rule->field_count; i++) {
@@ -747,8 +740,6 @@ static int audit_filter_rules(struct task_struct *tsk,
 	}
 
 	if (ctx) {
-		if (rule->prio <= ctx->prio)
-			return 0;
 		if (rule->filterkey) {
 			kfree(ctx->filterkey);
 			ctx->filterkey = kstrdup(rule->filterkey, GFP_ATOMIC);
@@ -1437,6 +1428,12 @@ static void show_special(struct audit_context *context, int *call_panic)
 		audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
 				 context->mmap.flags);
 		break;
+	case AUDIT_OPENAT2:
+		audit_log_format(ab, "oflag=0%llo mode=0%llo resolve=0x%llx",
+				 context->openat2.flags,
+				 context->openat2.mode,
+				 context->openat2.resolve);
+		break;
 	case AUDIT_EXECVE:
 		audit_log_execve_info(context, &ab);
 		break;
@@ -2815,6 +2812,16 @@ void __audit_mmap_fd(int fd, int flags)
 	context->type = AUDIT_MMAP;
 }
 
+void __audit_openat2_how(struct open_how *how)
+{
+	struct audit_context *context = audit_context();
+
+	context->openat2.flags = how->flags;
+	context->openat2.mode = how->mode;
+	context->openat2.resolve = how->resolve;
+	context->type = AUDIT_OPENAT2;
+}
+
 void __audit_log_kern_module(char *name)
 {
 	struct audit_context *context = audit_context();