[PATCH] audit string fields interface + consumer

Updated patch to dynamically allocate audit rule fields in kernel's
internal representation.  Added unlikely() calls for testing memory
allocation result.

Amy Griffis wrote:     [Wed Jan 11 2006, 02:02:31PM EST]
> Modify audit's kernel-userspace interface to allow the specification
> of string fields in audit rules.
>
> Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
(cherry picked from 5ffc4a863f92351b720fe3e9c5cd647accff9e03 commit)

include/linux/audit.h

@@ -50,15 +50,18 @@
  */
 #define AUDIT_GET		1000	/* Get status */
 #define AUDIT_SET		1001	/* Set status (enable/disable/auditd) */
-#define AUDIT_LIST		1002	/* List syscall filtering rules */
-#define AUDIT_ADD		1003	/* Add syscall filtering rule */
-#define AUDIT_DEL		1004	/* Delete syscall filtering rule */
+#define AUDIT_LIST		1002	/* List syscall rules -- deprecated */
+#define AUDIT_ADD		1003	/* Add syscall rule -- deprecated */
+#define AUDIT_DEL		1004	/* Delete syscall rule -- deprecated */
 #define AUDIT_USER		1005	/* Message from userspace -- deprecated */
 #define AUDIT_LOGIN		1006	/* Define the login id and information */
 #define AUDIT_WATCH_INS		1007	/* Insert file/dir watch entry */
 #define AUDIT_WATCH_REM		1008	/* Remove file/dir watch entry */
 #define AUDIT_WATCH_LIST	1009	/* List all file/dir watches */
 #define AUDIT_SIGNAL_INFO	1010	/* Get info about sender of signal to auditd */
+#define AUDIT_ADD_RULE		1011	/* Add syscall filtering rule */
+#define AUDIT_DEL_RULE		1012	/* Delete syscall filtering rule */
+#define AUDIT_LIST_RULES	1013	/* List syscall filtering rules */
 
 #define AUDIT_FIRST_USER_MSG	1100	/* Userspace messages mostly uninteresting to kernel */
 #define AUDIT_USER_AVC		1107	/* We filter this differently */
@@ -229,6 +232,26 @@ struct audit_status {
 	__u32		backlog;	/* messages waiting in queue */
 };
 
+/* audit_rule_data supports filter rules with both integer and string
+ * fields.  It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and
+ * AUDIT_LIST_RULES requests.
+ */
+struct audit_rule_data {
+	__u32		flags;	/* AUDIT_PER_{TASK,CALL}, AUDIT_PREPEND */
+	__u32		action;	/* AUDIT_NEVER, AUDIT_POSSIBLE, AUDIT_ALWAYS */
+	__u32		field_count;
+	__u32		mask[AUDIT_BITMASK_SIZE];
+	__u32		fields[AUDIT_MAX_FIELDS];
+	__u32		values[AUDIT_MAX_FIELDS];
+	__u32		fieldflags[AUDIT_MAX_FIELDS];
+	__u32		buflen;	/* total length of string fields */
+	char		buf[0];	/* string fields buffer */
+};
+
+/* audit_rule is supported to maintain backward compatibility with
+ * userspace.  It supports integer fields only and corresponds to
+ * AUDIT_ADD, AUDIT_DEL and AUDIT_LIST requests.
+ */
 struct audit_rule {		/* for AUDIT_LIST, AUDIT_ADD, and AUDIT_DEL */
 	__u32		flags;	/* AUDIT_PER_{TASK,CALL}, AUDIT_PREPEND */
 	__u32		action;	/* AUDIT_NEVER, AUDIT_POSSIBLE, AUDIT_ALWAYS */
@@ -338,7 +361,7 @@ extern void		    audit_log_d_path(struct audit_buffer *ab,
 extern int audit_filter_user(struct netlink_skb_parms *cb, int type);
 extern int audit_filter_type(int type);
 extern int  audit_receive_filter(int type, int pid, int uid, int seq,
-				 void *data, uid_t loginuid);
+				 void *data, size_t datasz, uid_t loginuid);
 #else
 #define audit_log(c,g,t,f,...) do { ; } while (0)
 #define audit_log_start(c,g,t) ({ NULL; })

kernel/audit.c

@@ -52,6 +52,7 @@
 #include <linux/audit.h>
 
 #include <net/sock.h>
+#include <net/netlink.h>
 #include <linux/skbuff.h>
 #include <linux/netlink.h>
 
@@ -361,9 +362,12 @@ static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type)
 	switch (msg_type) {
 	case AUDIT_GET:
 	case AUDIT_LIST:
+	case AUDIT_LIST_RULES:
 	case AUDIT_SET:
 	case AUDIT_ADD:
+	case AUDIT_ADD_RULE:
 	case AUDIT_DEL:
+	case AUDIT_DEL_RULE:
 	case AUDIT_SIGNAL_INFO:
 		if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL))
 			err = -EPERM;
@@ -470,12 +474,23 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		break;
 	case AUDIT_ADD:
 	case AUDIT_DEL:
-		if (nlh->nlmsg_len < sizeof(struct audit_rule))
+		if (nlmsg_len(nlh) < sizeof(struct audit_rule))
 			return -EINVAL;
 		/* fallthrough */
 	case AUDIT_LIST:
 		err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
-					   uid, seq, data, loginuid);
+					   uid, seq, data, nlmsg_len(nlh),
+					   loginuid);
+		break;
+	case AUDIT_ADD_RULE:
+	case AUDIT_DEL_RULE:
+		if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
+			return -EINVAL;
+		/* fallthrough */
+	case AUDIT_LIST_RULES:
+		err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
+					   uid, seq, data, nlmsg_len(nlh),
+					   loginuid);
 		break;
 	case AUDIT_SIGNAL_INFO:
 		sig_data.uid = audit_sig_uid;

kernel/audit.h

@@ -52,10 +52,27 @@ enum audit_state {
 };
 
 /* Rule lists */
+struct audit_field {
+	u32			type;
+	u32			val;
+	u32			op;
+};
+
+struct audit_krule {
+	int			vers_ops;
+	u32			flags;
+	u32			listnr;
+	u32			action;
+	u32			mask[AUDIT_BITMASK_SIZE];
+	u32			buflen; /* for data alloc on list rules */
+	u32			field_count;
+	struct audit_field	*fields;
+};
+
 struct audit_entry {
-	struct list_head  list;
-	struct rcu_head   rcu;
-	struct audit_rule rule;
+	struct list_head	list;
+	struct rcu_head		rcu;
+	struct audit_krule	rule;
 };
 
 

kernel/auditsc.c

@@ -162,70 +162,68 @@ struct audit_context {
 /* Compare a task_struct with an audit_rule.  Return 1 on match, 0
  * otherwise. */
 static int audit_filter_rules(struct task_struct *tsk,
-			      struct audit_rule *rule,
+			      struct audit_krule *rule,
 			      struct audit_context *ctx,
 			      enum audit_state *state)
 {
 	int i, j;
 
 	for (i = 0; i < rule->field_count; i++) {
-		u32 field  = rule->fields[i] & ~AUDIT_OPERATORS;
-		u32 op  = rule->fields[i] & AUDIT_OPERATORS;
-		u32 value  = rule->values[i];
+		struct audit_field *f = &rule->fields[i];
 		int result = 0;
 
-		switch (field) {
+		switch (f->type) {
 		case AUDIT_PID:
-			result = audit_comparator(tsk->pid, op, value);
+			result = audit_comparator(tsk->pid, f->op, f->val);
 			break;
 		case AUDIT_UID:
-			result = audit_comparator(tsk->uid, op, value);
+			result = audit_comparator(tsk->uid, f->op, f->val);
 			break;
 		case AUDIT_EUID:
-			result = audit_comparator(tsk->euid, op, value);
+			result = audit_comparator(tsk->euid, f->op, f->val);
 			break;
 		case AUDIT_SUID:
-			result = audit_comparator(tsk->suid, op, value);
+			result = audit_comparator(tsk->suid, f->op, f->val);
 			break;
 		case AUDIT_FSUID:
-			result = audit_comparator(tsk->fsuid, op, value);
+			result = audit_comparator(tsk->fsuid, f->op, f->val);
 			break;
 		case AUDIT_GID:
-			result = audit_comparator(tsk->gid, op, value);
+			result = audit_comparator(tsk->gid, f->op, f->val);
 			break;
 		case AUDIT_EGID:
-			result = audit_comparator(tsk->egid, op, value);
+			result = audit_comparator(tsk->egid, f->op, f->val);
 			break;
 		case AUDIT_SGID:
-			result = audit_comparator(tsk->sgid, op, value);
+			result = audit_comparator(tsk->sgid, f->op, f->val);
 			break;
 		case AUDIT_FSGID:
-			result = audit_comparator(tsk->fsgid, op, value);
+			result = audit_comparator(tsk->fsgid, f->op, f->val);
 			break;
 		case AUDIT_PERS:
-			result = audit_comparator(tsk->personality, op, value);
+			result = audit_comparator(tsk->personality, f->op, f->val);
 			break;
 		case AUDIT_ARCH:
  			if (ctx)
-				result = audit_comparator(ctx->arch, op, value);
+				result = audit_comparator(ctx->arch, f->op, f->val);
 			break;
 
 		case AUDIT_EXIT:
 			if (ctx && ctx->return_valid)
-				result = audit_comparator(ctx->return_code, op, value);
+				result = audit_comparator(ctx->return_code, f->op, f->val);
 			break;
 		case AUDIT_SUCCESS:
 			if (ctx && ctx->return_valid) {
-				if (value)
-					result = audit_comparator(ctx->return_valid, op, AUDITSC_SUCCESS);
+				if (f->val)
+					result = audit_comparator(ctx->return_valid, f->op, AUDITSC_SUCCESS);
 				else
-					result = audit_comparator(ctx->return_valid, op, AUDITSC_FAILURE);
+					result = audit_comparator(ctx->return_valid, f->op, AUDITSC_FAILURE);
 			}
 			break;
 		case AUDIT_DEVMAJOR:
 			if (ctx) {
 				for (j = 0; j < ctx->name_count; j++) {
-					if (audit_comparator(MAJOR(ctx->names[j].dev),	op, value)) {
+					if (audit_comparator(MAJOR(ctx->names[j].dev),	f->op, f->val)) {
 						++result;
 						break;
 					}
@@ -235,7 +233,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 		case AUDIT_DEVMINOR:
 			if (ctx) {
 				for (j = 0; j < ctx->name_count; j++) {
-					if (audit_comparator(MINOR(ctx->names[j].dev), op, value)) {
+					if (audit_comparator(MINOR(ctx->names[j].dev), f->op, f->val)) {
 						++result;
 						break;
 					}
@@ -245,8 +243,8 @@ static int audit_filter_rules(struct task_struct *tsk,
 		case AUDIT_INODE:
 			if (ctx) {
 				for (j = 0; j < ctx->name_count; j++) {
-					if (audit_comparator(ctx->names[j].ino, op, value) ||
-					    audit_comparator(ctx->names[j].pino, op, value)) {
+					if (audit_comparator(ctx->names[j].ino, f->op, f->val) ||
+					    audit_comparator(ctx->names[j].pino, f->op, f->val)) {
 						++result;
 						break;
 					}
@@ -256,14 +254,14 @@ static int audit_filter_rules(struct task_struct *tsk,
 		case AUDIT_LOGINUID:
 			result = 0;
 			if (ctx)
-				result = audit_comparator(ctx->loginuid, op, value);
+				result = audit_comparator(ctx->loginuid, f->op, f->val);
 			break;
 		case AUDIT_ARG0:
 		case AUDIT_ARG1:
 		case AUDIT_ARG2:
 		case AUDIT_ARG3:
 			if (ctx)
-				result = audit_comparator(ctx->argv[field-AUDIT_ARG0], op, value);
+				result = audit_comparator(ctx->argv[f->type-AUDIT_ARG0], f->op, f->val);
 			break;
 		}
 

security/selinux/nlmsgtab.c

@@ -99,6 +99,9 @@ static struct nlmsg_perm nlmsg_audit_perms[] =
 	{ AUDIT_LIST,		NETLINK_AUDIT_SOCKET__NLMSG_READPRIV },
 	{ AUDIT_ADD,		NETLINK_AUDIT_SOCKET__NLMSG_WRITE    },
 	{ AUDIT_DEL,		NETLINK_AUDIT_SOCKET__NLMSG_WRITE    },
+	{ AUDIT_LIST_RULES,	NETLINK_AUDIT_SOCKET__NLMSG_READPRIV },
+	{ AUDIT_ADD_RULE,	NETLINK_AUDIT_SOCKET__NLMSG_WRITE    },
+	{ AUDIT_DEL_RULE,	NETLINK_AUDIT_SOCKET__NLMSG_WRITE    },
 	{ AUDIT_USER,		NETLINK_AUDIT_SOCKET__NLMSG_RELAY    },
 	{ AUDIT_SIGNAL_INFO,	NETLINK_AUDIT_SOCKET__NLMSG_READ     },
 };