Smack: allow for significantly longer Smack labels v4

V4 updated to current linux-security#next
Targeted for git://gitorious.org/smack-next/kernel.git

Modern application runtime environments like to use
naming schemes that are structured and generated without
human intervention. Even though the Smack limit of 23
characters for a label name is perfectly rational for
human use there have been complaints that the limit is
a problem in environments where names are composed from
a set or sources, including vendor, author, distribution
channel and application name. Names like

	softwarehouse-pgwodehouse-coolappstore-mellowmuskrats

are becoming harder to avoid. This patch introduces long
label support in Smack. Labels are now limited to 255
characters instead of the old 23.

The primary reason for limiting the labels to 23 characters
was so they could be directly contained in CIPSO category sets.
This is still done were possible, but for labels that are too
large a mapping is required. This is perfectly safe for communication
that stays "on the box" and doesn't require much coordination
between boxes beyond what would have been required to keep label
names consistent.

The bulk of this patch is in smackfs, adding and updating
administrative interfaces. Because existing APIs can't be
changed new ones that do much the same things as old ones
have been introduced.

The Smack specific CIPSO data representation has been removed
and replaced with the data format used by netlabel. The CIPSO
header is now computed when a label is imported rather than
on use. This results in improved IP performance. The smack
label is now allocated separately from the containing structure,
allowing for larger strings.

Four new /smack interfaces have been introduced as four
of the old interfaces strictly required labels be specified
in fixed length arrays.

The access interface is supplemented with the check interface:
	access  "Subject                 Object                  rwxat"
	access2 "Subject Object rwaxt"

The load interface is supplemented with the rules interface:
	load   "Subject                 Object                  rwxat"
	load2  "Subject Object rwaxt"

The load-self interface is supplemented with the self-rules interface:
	load-self   "Subject                 Object                  rwxat"
	load-self2  "Subject Object rwaxt"

The cipso interface is supplemented with the wire interface:
	cipso  "Subject                  lvl cnt  c1  c2 ..."
	cipso2 "Subject lvl cnt  c1  c2 ..."

The old interfaces are maintained for compatibility.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

1 files changed, 20 insertions, 36 deletions

diff --git a/security/smack/smack.h b/security/smack/smack.h
index cf2594d..5e031a2 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -23,13 +23,19 @@
 #include <linux/lsm_audit.h>
 
 /*
+ * Smack labels were limited to 23 characters for a long time.
+ */
+#define SMK_LABELLEN	24
+#define SMK_LONGLABEL	256
+
+/*
+ * Maximum number of bytes for the levels in a CIPSO IP option.
  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  * bigger than can be used, and 24 is the next lower multiple
  * of 8, and there are too many issues if there isn't space set
  * aside for the terminating null byte.
  */
-#define SMK_MAXLEN	23
-#define SMK_LABELLEN	(SMK_MAXLEN+1)
+#define SMK_CIPSOLEN	24
 
 struct superblock_smack {
 	char		*smk_root;
@@ -79,15 +85,6 @@ struct smack_rule {
 };
 
 /*
- * An entry in the table mapping smack values to
- * CIPSO level/category-set values.
- */
-struct smack_cipso {
-	int	smk_level;
-	char	smk_catset[SMK_LABELLEN];
-};
-
-/*
  * An entry in the table identifying hosts.
  */
 struct smk_netlbladdr {
@@ -114,22 +111,19 @@ struct smk_netlbladdr {
  * interfaces don't. The secid should go away when all of
  * these components have been repaired.
  *
- * If there is a cipso value associated with the label it
- * gets stored here, too. This will most likely be rare as
- * the cipso direct mapping in used internally.
+ * The cipso value associated with the label gets stored here, too.
  *
  * Keep the access rules for this subject label here so that
  * the entire set of rules does not need to be examined every
  * time.
  */
 struct smack_known {
-	struct list_head	list;
-	char			smk_known[SMK_LABELLEN];
-	u32			smk_secid;
-	struct smack_cipso	*smk_cipso;
-	spinlock_t		smk_cipsolock;	/* for changing cipso map */
-	struct list_head	smk_rules;	/* access rules */
-	struct mutex		smk_rules_lock;	/* lock for the rules */
+	struct list_head		list;
+	char				*smk_known;
+	u32				smk_secid;
+	struct netlbl_lsm_secattr	smk_netlabel;	/* on wire labels */
+	struct list_head		smk_rules;	/* access rules */
+	struct mutex			smk_rules_lock;	/* lock for rules */
 };
 
 /*
@@ -166,6 +160,7 @@ struct smack_known {
 #define SMACK_CIPSO_DOI_DEFAULT		3	/* Historical */
 #define SMACK_CIPSO_DOI_INVALID		-1	/* Not a DOI */
 #define SMACK_CIPSO_DIRECT_DEFAULT	250	/* Arbitrary */
+#define SMACK_CIPSO_MAPPED_DEFAULT	251	/* Also arbitrary */
 #define SMACK_CIPSO_MAXCATVAL		63	/* Bigger gets harder */
 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
@@ -216,10 +211,9 @@ struct inode_smack *new_inode_smack(char *);
 int smk_access_entry(char *, char *, struct list_head *);
 int smk_access(char *, char *, int, struct smk_audit_info *);
 int smk_curacc(char *, u32, struct smk_audit_info *);
-int smack_to_cipso(const char *, struct smack_cipso *);
-char *smack_from_cipso(u32, char *);
 char *smack_from_secid(const u32);
-void smk_parse_smack(const char *string, int len, char *smack);
+char *smk_parse_smack(const char *string, int len);
+int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 char *smk_import(const char *, int);
 struct smack_known *smk_import_entry(const char *, int);
 struct smack_known *smk_find_entry(const char *);
@@ -229,6 +223,7 @@ u32 smack_to_secid(const char *);
  * Shared data.
  */
 extern int smack_cipso_direct;
+extern int smack_cipso_mapped;
 extern char *smack_net_ambient;
 extern char *smack_onlycap;
 extern const char *smack_cipso_option;
@@ -240,24 +235,13 @@ extern struct smack_known smack_known_invalid;
 extern struct smack_known smack_known_star;
 extern struct smack_known smack_known_web;
 
+extern struct mutex	smack_known_lock;
 extern struct list_head smack_known_list;
 extern struct list_head smk_netlbladdr_list;
 
 extern struct security_operations smack_ops;
 
 /*
- * Stricly for CIPSO level manipulation.
- * Set the category bit number in a smack label sized buffer.
- */
-static inline void smack_catset_bit(int cat, char *catsetp)
-{
-	if (cat > SMK_LABELLEN * 8)
-		return;
-
-	catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
-}
-
-/*
  * Is the directory transmuting?
  */
 static inline int smk_inode_transmutable(const struct inode *isp)