prevent the use of permit for aliases. from provos

4 files changed, 49 insertions, 9 deletions

diff --git a/bin/systrace/filter.c b/bin/systrace/filter.c
index 6525083f1db..3401ae1da38 100644
--- a/bin/systrace/filter.c
+++ b/bin/systrace/filter.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: filter.c,v 1.22 2002/11/15 22:33:27 itojun Exp $	*/
+/*	$OpenBSD: filter.c,v 1.23 2002/12/09 07:22:52 itojun Exp $	*/
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
@@ -472,14 +472,17 @@ filter_ask(int fd, struct intercept_tlq *tls, struct filterq *fls,
     char *output, short *pfuture, struct intercept_pid *icpid)
 {
 	char line[2*MAXPATHLEN], *p;
+	char compose[2*MAXPATHLEN];
 	struct filter *filter;
 	struct policy *policy;
 	short action;
-	int first = 1;
+	int first = 1, isalias;
 
 	*pfuture = ICPOLICY_ASK;
 	icpid->uflags = 0;
 
+	isalias = systrace_find_reverse(emulation, name) != NULL;
+
 	if ((policy = systrace_findpolnr(policynr)) == NULL)
 		errx(1, "%s:%d: no policy %d", __func__, __LINE__, policynr);
 
@@ -489,8 +492,7 @@ filter_ask(int fd, struct intercept_tlq *tls, struct filterq *fls,
 		/* Automatically allow */
 		if (tls != NULL) {
 			struct intercept_translate *tl;
-			char compose[2*MAXPATHLEN], *l;
-			char *lst = NULL;
+			char *l, *lst = NULL;
 			int set = 0;
 
 			/* Explicitly match every component */
@@ -591,7 +593,15 @@ filter_ask(int fd, struct intercept_tlq *tls, struct filterq *fls,
 		if (filter_parse_simple(line, &action, pfuture) != -1) {
 			if (*pfuture == ICPOLICY_ASK)
 				goto out;
-			break;
+			/* We have a policy decision */
+			if (!isalias)
+				break;
+
+			/* No in-kernel policy for aliases */
+			strlcpy(compose, line, sizeof(compose));
+			
+			/* Change into userland rule */
+			snprintf(line, sizeof(line), "true then %s", compose);
 		}
 
 		if (fls == NULL) {
diff --git a/bin/systrace/intercept.c b/bin/systrace/intercept.c
index 2775407a283..a2076cf1d4c 100644
--- a/bin/systrace/intercept.c
+++ b/bin/systrace/intercept.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: intercept.c,v 1.36 2002/11/26 03:48:07 itojun Exp $	*/
+/*	$OpenBSD: intercept.c,v 1.37 2002/12/09 07:22:53 itojun Exp $	*/
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
@@ -873,3 +873,18 @@ intercept_ugid(struct intercept_pid *icpid, uid_t uid, gid_t gid)
 	icpid->uid = uid;
 	icpid->gid = gid;
 }
+
+/*
+ * Checks if the given emulation has a certain system call.
+ * This is a very slow function.
+ */
+
+int
+intercept_isvalidsystemcall(char *emulation, char *name)
+{
+	int res;
+
+	res = intercept.getsyscallnumber(emulation, name);
+
+	return (res != -1);
+}
diff --git a/bin/systrace/intercept.h b/bin/systrace/intercept.h
index e0d4101ea82..f6f38c69761 100644
--- a/bin/systrace/intercept.h
+++ b/bin/systrace/intercept.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: intercept.h,v 1.14 2002/11/26 03:48:07 itojun Exp $	*/
+/*	$OpenBSD: intercept.h,v 1.15 2002/12/09 07:22:53 itojun Exp $	*/
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
@@ -190,4 +190,6 @@ void intercept_syscall_result(int, pid_t, u_int16_t, int, const char *, int,
 void intercept_ugid(struct intercept_pid *, uid_t, gid_t);
 void intercept_setpid(struct intercept_pid *, uid_t, gid_t);
 
+int intercept_isvalidsystemcall(char *, char *);
+
 #endif /* _INTERCEPT_H_ */
diff --git a/bin/systrace/policy.c b/bin/systrace/policy.c
index 2488d3c7b82..fbdb57e22d7 100644
--- a/bin/systrace/policy.c
+++ b/bin/systrace/policy.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: policy.c,v 1.21 2002/10/09 03:52:10 itojun Exp $	*/
+/*	$OpenBSD: policy.c,v 1.22 2002/12/09 07:22:53 itojun Exp $	*/
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
@@ -522,7 +522,7 @@ systrace_policyprocess(struct policy *policy, char *p)
 	char *name, *emulation, *rule;
 	struct filter *filter, *parsed;
 	short action, future;
-	int  resolved = 0, res;
+	int  resolved = 0, res, isvalid;
 
 	/* Delay predicate evaluation if we are root */
 
@@ -536,6 +536,9 @@ systrace_policyprocess(struct policy *policy, char *p)
 	name = strsep(&p, ":");
 	if (p == NULL || *p != ' ')
 		return (-1);
+
+	isvalid = intercept_isvalidsystemcall(emulation, name);
+
 	p++;
 	rule = p;
 
@@ -551,6 +554,16 @@ systrace_policyprocess(struct policy *policy, char *p)
 	} else if (filter_parse_simple(rule, &action, &future) == 0)
 		resolved = 1;
 
+	/* For now, everything that does not seem to be a valid syscall
+	 * does not get fast kernel policies even though the aliasing
+	 * system supports it.
+	 */
+	if (resolved && !isvalid) {
+		resolved = 0;
+		snprintf(line, sizeof(line), "true then %s", rule);
+		rule = line;
+	}
+
 	/* If the simple parser did not match, try real parser */
 	if (!resolved) {
 		if (parse_filter(rule, &parsed) == -1)