Use strsep() in preference to manual string parsing for Biba and MLS

label internalization.  Use sensible variable names.  Include comments.
Doesn't fix any known bugs, but may fix unknown ones.

Approved by:	re (scottl)

1 files changed, 39 insertions, 48 deletions

diff --git a/sys/security/mac_mls/mac_mls.c b/sys/security/mac_mls/mac_mls.c
index f6d69d6..6501f9c 100644
--- a/sys/security/mac_mls/mac_mls.c
+++ b/sys/security/mac_mls/mac_mls.c
@@ -613,6 +613,8 @@ mac_mls_externalize_label(struct label *label, char *element_name,
 static int
 mac_mls_parse_element(struct mac_mls_element *element, char *string)
 {
+	char *compartment, *end, *level;
+	int value;
 
 	if (strcmp(string, "high") == 0 ||
 	    strcmp(string, "hi") == 0) {
@@ -627,38 +629,36 @@ mac_mls_parse_element(struct mac_mls_element *element, char *string)
 		element->mme_type = MAC_MLS_TYPE_EQUAL;
 		element->mme_level = MAC_MLS_TYPE_UNDEF;
 	} else {
-		char *p0, *p1;
-		int d;
-
-		p0 = string;
-		d = strtol(p0, &p1, 10);
+		element->mme_type = MAC_MLS_TYPE_LEVEL;
 
-		if (d < 0 || d > 65535)
+		/*
+		 * Numeric level piece of the element.
+		 */
+		level = strsep(&string, ":");
+		value = strtol(level, &end, 10);
+		if (end == level || *end != '\0')
 			return (EINVAL);
-		element->mme_type = MAC_MLS_TYPE_LEVEL;
-		element->mme_level = d;
+		if (value < 0 || value > 65535)
+			return (EINVAL);
+		element->mme_level = value;
 
-		if (*p1 != ':')  {
-			if (p1 == p0 || *p1 != '\0')
-				return (EINVAL);
-			else
-				return (0);
-		}
-		else
-			if (*(p1 + 1) == '\0')
-				return (0);
+		/*
+		 * Optional compartment piece of the element.  If none
+		 * are included, we assume that the label has no
+		 * compartments.
+		 */
+		if (string == NULL)
+			return (0);
+		if (*string == '\0')
+			return (0);
 
-		while ((p0 = ++p1)) {
-			d = strtol(p0, &p1, 10);
-			if (d < 1 || d > MAC_MLS_MAX_COMPARTMENTS)
+		while ((compartment = strsep(&string, "+")) != NULL) {
+			value = strtol(compartment, &end, 10);
+			if (compartment == end || *end != '\0')
 				return (EINVAL);
-
-			MAC_MLS_BIT_SET(d, element->mme_compartments);
-
-			if (*p1 == '\0')
-				break;
-			if (p1 == p0 || *p1 != '+')
+			if (value < 1 || value > MAC_MLS_MAX_COMPARTMENTS)
 				return (EINVAL);
+			MAC_MLS_BIT_SET(value, element->mme_compartments);
 		}
 	}
 
@@ -675,35 +675,26 @@ mac_mls_parse(struct mac_mls *mac_mls, char *string)
 	char *range, *rangeend, *rangehigh, *rangelow, *single;
 	int error;
 
-	/* Do we have a range? */
-	single = string;
-	range = index(string, '(');
-	if (range == single)
+	single = strsep(&string, "(");
+	if (string == NULL) {
+		string = single;
 		single = NULL;
-	rangelow = rangehigh = NULL;
-	if (range != NULL) {
-		/* Nul terminate the end of the single string. */
-		*range = '\0';
-		range++;
-		rangelow = range;
-		rangehigh = index(rangelow, '-');
-		if (rangehigh == NULL)
-			return (EINVAL);
-		rangehigh++;
-		if (*rangelow == '\0' || *rangehigh == '\0')
+	}
+
+	if (string != NULL) {
+		rangelow = strsep(&string, "-");
+		if (string == NULL)
 			return (EINVAL);
-		rangeend = index(rangehigh, ')');
-		if (rangeend == NULL)
+		rangehigh = strsep(&string, ")");
+		if (string == NULL)
 			return (EINVAL);
-		if (*(rangeend + 1) != '\0')
+		if (*string != '\0')
 			return (EINVAL);
-		/* Nul terminate the ends of the ranges. */
-		*(rangehigh - 1) = '\0';
-		*rangeend = '\0';
 	}
+
 	KASSERT((rangelow != NULL && rangehigh != NULL) ||
 	    (rangelow == NULL && rangehigh == NULL),
-	    ("mac_mls_internalize_label: range mismatch"));
+	    ("mac_mls_parse: range mismatch"));
 
 	bzero(mac_mls, sizeof(*mac_mls));
 	if (single != NULL) {