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-rw-r--r--security/selinux/ss/mls.c71
1 files changed, 48 insertions, 23 deletions
diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c
index 756036bcc243..d4c32c39ccc9 100644
--- a/security/selinux/ss/mls.c
+++ b/security/selinux/ss/mls.c
@@ -15,6 +15,7 @@
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
+#include "sidtab.h"
#include "mls.h"
#include "policydb.h"
#include "services.h"
@@ -208,6 +209,26 @@ int mls_context_isvalid(struct policydb *p, struct context *c)
}
/*
+ * Copies the MLS range from `src' into `dst'.
+ */
+static inline int mls_copy_context(struct context *dst,
+ struct context *src)
+{
+ int l, rc = 0;
+
+ /* Copy the MLS range from the source context */
+ for (l = 0; l < 2; l++) {
+ dst->range.level[l].sens = src->range.level[l].sens;
+ rc = ebitmap_cpy(&dst->range.level[l].cat,
+ &src->range.level[l].cat);
+ if (rc)
+ break;
+ }
+
+ return rc;
+}
+
+/*
* Set the MLS fields in the security context structure
* `context' based on the string representation in
* the string `*scontext'. Update `*scontext' to
@@ -216,10 +237,20 @@ int mls_context_isvalid(struct policydb *p, struct context *c)
*
* This function modifies the string in place, inserting
* NULL characters to terminate the MLS fields.
+ *
+ * If a def_sid is provided and no MLS field is present,
+ * copy the MLS field of the associated default context.
+ * Used for upgraded to MLS systems where objects may lack
+ * MLS fields.
+ *
+ * Policy read-lock must be held for sidtab lookup.
+ *
*/
int mls_context_to_sid(char oldc,
char **scontext,
- struct context *context)
+ struct context *context,
+ struct sidtab *s,
+ u32 def_sid)
{
char delim;
@@ -231,9 +262,23 @@ int mls_context_to_sid(char oldc,
if (!selinux_mls_enabled)
return 0;
- /* No MLS component to the security context. */
- if (!oldc)
+ /*
+ * No MLS component to the security context, try and map to
+ * default if provided.
+ */
+ if (!oldc) {
+ struct context *defcon;
+
+ if (def_sid == SECSID_NULL)
+ goto out;
+
+ defcon = sidtab_search(s, def_sid);
+ if (!defcon)
+ goto out;
+
+ rc = mls_copy_context(context, defcon);
goto out;
+ }
/* Extract low sensitivity. */
scontextp = p = *scontext;
@@ -334,26 +379,6 @@ out:
}
/*
- * Copies the MLS range from `src' into `dst'.
- */
-static inline int mls_copy_context(struct context *dst,
- struct context *src)
-{
- int l, rc = 0;
-
- /* Copy the MLS range from the source context */
- for (l = 0; l < 2; l++) {
- dst->range.level[l].sens = src->range.level[l].sens;
- rc = ebitmap_cpy(&dst->range.level[l].cat,
- &src->range.level[l].cat);
- if (rc)
- break;
- }
-
- return rc;
-}
-
-/*
* Copies the effective MLS range from `src' into `dst'.
*/
static inline int mls_scopy_context(struct context *dst,