NetLabel: convert to an extensibile/sparse category bitmap

The original NetLabel category bitmap was a straight char bitmap which worked
fine for the initial release as it only supported 240 bits due to limitations
in the CIPSO restricted bitmap tag (tag type 0x01).  This patch converts that
straight char bitmap into an extensibile/sparse bitmap in order to lay the
foundation for other CIPSO tag types and protocols.

This patch also has a nice side effect in that all of the security attributes
passed by NetLabel into the LSM are now in a format which is in the host's
native byte/bit ordering which makes the LSM specific code much simpler; look
at the changes in security/selinux/ss/ebitmap.c as an example.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 51 insertions, 105 deletions

diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c
index 2cca8e251624..b4f682dc13ff 100644
--- a/security/selinux/ss/mls.c
+++ b/security/selinux/ss/mls.c
@@ -13,7 +13,7 @@
 /*
  * Updated: Hewlett-Packard <paul.moore@hp.com>
  *
- *      Added support to import/export the MLS label
+ *      Added support to import/export the MLS label from NetLabel
  *
  * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
  */
@@ -22,6 +22,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/errno.h>
+#include <net/netlabel.h>
 #include "sidtab.h"
 #include "mls.h"
 #include "policydb.h"
@@ -571,163 +572,108 @@ int mls_compute_sid(struct context *scontext,
 	return -EINVAL;
 }
 
+#ifdef CONFIG_NETLABEL
 /**
- * mls_export_lvl - Export the MLS sensitivity levels
+ * mls_export_netlbl_lvl - Export the MLS sensitivity levels to NetLabel
  * @context: the security context
- * @low: the low sensitivity level
- * @high: the high sensitivity level
+ * @secattr: the NetLabel security attributes
  *
  * Description:
- * Given the security context copy the low MLS sensitivity level into lvl_low
- * and the high sensitivity level in lvl_high.  The MLS levels are only
- * exported if the pointers are not NULL, if they are NULL then that level is
- * not exported.
+ * Given the security context copy the low MLS sensitivity level into the
+ * NetLabel MLS sensitivity level field.
  *
  */
-void mls_export_lvl(const struct context *context, u32 *low, u32 *high)
+void mls_export_netlbl_lvl(struct context *context,
+			   struct netlbl_lsm_secattr *secattr)
 {
 	if (!selinux_mls_enabled)
 		return;
 
-	if (low != NULL)
-		*low = context->range.level[0].sens - 1;
-	if (high != NULL)
-		*high = context->range.level[1].sens - 1;
+	secattr->mls_lvl = context->range.level[0].sens - 1;
+	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
 }
 
 /**
- * mls_import_lvl - Import the MLS sensitivity levels
+ * mls_import_netlbl_lvl - Import the NetLabel MLS sensitivity levels
  * @context: the security context
- * @low: the low sensitivity level
- * @high: the high sensitivity level
+ * @secattr: the NetLabel security attributes
  *
  * Description:
- * Given the security context and the two sensitivty levels, set the MLS levels
- * in the context according the two given as parameters.  Returns zero on
- * success, negative values on failure.
+ * Given the security context and the NetLabel security attributes, copy the
+ * NetLabel MLS sensitivity level into the context.
  *
  */
-void mls_import_lvl(struct context *context, u32 low, u32 high)
+void mls_import_netlbl_lvl(struct context *context,
+			   struct netlbl_lsm_secattr *secattr)
 {
 	if (!selinux_mls_enabled)
 		return;
 
-	context->range.level[0].sens = low + 1;
-	context->range.level[1].sens = high + 1;
+	context->range.level[0].sens = secattr->mls_lvl + 1;
+	context->range.level[1].sens = context->range.level[0].sens;
 }
 
 /**
- * mls_export_cat - Export the MLS categories
+ * mls_export_netlbl_cat - Export the MLS categories to NetLabel
  * @context: the security context
- * @low: the low category
- * @low_len: length of the cat_low bitmap in bytes
- * @high: the high category
- * @high_len: length of the cat_high bitmap in bytes
+ * @secattr: the NetLabel security attributes
  *
  * Description:
- * Given the security context export the low MLS category bitmap into cat_low
- * and the high category bitmap into cat_high.  The MLS categories are only
- * exported if the pointers are not NULL, if they are NULL then that level is
- * not exported.  The caller is responsibile for freeing the memory when
- * finished.  Returns zero on success, negative values on failure.
+ * Given the security context copy the low MLS categories into the NetLabel
+ * MLS category field.  Returns zero on success, negative values on failure.
  *
  */
-int mls_export_cat(const struct context *context,
-		   unsigned char **low,
-		   size_t *low_len,
-		   unsigned char **high,
-		   size_t *high_len)
+int mls_export_netlbl_cat(struct context *context,
+			  struct netlbl_lsm_secattr *secattr)
 {
-	int rc = -EPERM;
+	int rc;
 
-	if (!selinux_mls_enabled) {
-		*low = NULL;
-		*low_len = 0;
-		*high = NULL;
-		*high_len = 0;
+	if (!selinux_mls_enabled)
 		return 0;
-	}
 
-	if (low != NULL) {
-		rc = ebitmap_export(&context->range.level[0].cat,
-				    low,
-				    low_len);
-		if (rc != 0)
-			goto export_cat_failure;
-	}
-	if (high != NULL) {
-		rc = ebitmap_export(&context->range.level[1].cat,
-				    high,
-				    high_len);
-		if (rc != 0)
-			goto export_cat_failure;
-	}
-
-	return 0;
+	rc = ebitmap_netlbl_export(&context->range.level[0].cat,
+				   &secattr->mls_cat);
+	if (rc == 0 && secattr->mls_cat != NULL)
+		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
 
-export_cat_failure:
-	if (low != NULL) {
-		kfree(*low);
-		*low = NULL;
-		*low_len = 0;
-	}
-	if (high != NULL) {
-		kfree(*high);
-		*high = NULL;
-		*high_len = 0;
-	}
 	return rc;
 }
 
 /**
- * mls_import_cat - Import the MLS categories
+ * mls_import_netlbl_cat - Import the MLS categories from NetLabel
  * @context: the security context
- * @low: the low category
- * @low_len: length of the cat_low bitmap in bytes
- * @high: the high category
- * @high_len: length of the cat_high bitmap in bytes
+ * @secattr: the NetLabel security attributes
  *
  * Description:
- * Given the security context and the two category bitmap strings import the
- * categories into the security context.  The MLS categories are only imported
- * if the pointers are not NULL, if they are NULL they are skipped.  Returns
- * zero on success, negative values on failure.
+ * Copy the NetLabel security attributes into the SELinux context; since the
+ * NetLabel security attribute only contains a single MLS category use it for
+ * both the low and high categories of the context.  Returns zero on success,
+ * negative values on failure.
  *
  */
-int mls_import_cat(struct context *context,
-		   const unsigned char *low,
-		   size_t low_len,
-		   const unsigned char *high,
-		   size_t high_len)
+int mls_import_netlbl_cat(struct context *context,
+			  struct netlbl_lsm_secattr *secattr)
 {
-	int rc = -EPERM;
+	int rc;
 
 	if (!selinux_mls_enabled)
 		return 0;
 
-	if (low != NULL) {
-		rc = ebitmap_import(low,
-				    low_len,
-				    &context->range.level[0].cat);
-		if (rc != 0)
-			goto import_cat_failure;
-	}
-	if (high != NULL) {
-		if (high == low)
-			rc = ebitmap_cpy(&context->range.level[1].cat,
-					 &context->range.level[0].cat);
-		else
-			rc = ebitmap_import(high,
-					    high_len,
-					    &context->range.level[1].cat);
-		if (rc != 0)
-			goto import_cat_failure;
-	}
+	rc = ebitmap_netlbl_import(&context->range.level[0].cat,
+				   secattr->mls_cat);
+	if (rc != 0)
+		goto import_netlbl_cat_failure;
+
+	rc = ebitmap_cpy(&context->range.level[1].cat,
+			 &context->range.level[0].cat);
+	if (rc != 0)
+		goto import_netlbl_cat_failure;
 
 	return 0;
 
-import_cat_failure:
+import_netlbl_cat_failure:
 	ebitmap_destroy(&context->range.level[0].cat);
 	ebitmap_destroy(&context->range.level[1].cat);
 	return rc;
 }
+#endif /* CONFIG_NETLABEL */