1 files changed, 79 insertions, 2 deletions

diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c
index 04b6145d767f..d42951fcbe87 100644
--- a/security/selinux/ss/ebitmap.c
+++ b/security/selinux/ss/ebitmap.c
@@ -22,6 +22,8 @@
 #include "ebitmap.h"
 #include "policydb.h"
 
+#define BITS_PER_U64    (sizeof(u64) * 8)
+
 int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2)
 {
         struct ebitmap_node *n1, *n2;
@@ -363,10 +365,10 @@ int ebitmap_read(struct ebitmap *e, void *fp)
         e->highbit = le32_to_cpu(buf[1]);
         count = le32_to_cpu(buf[2]);
 
-        if (mapunit != sizeof(u64) * 8) {
+        if (mapunit != BITS_PER_U64) {
                 printk(KERN_ERR "SELinux: ebitmap: map size %u does not "
                        "match my size %Zd (high bit was %d)\n",
-                       mapunit, sizeof(u64) * 8, e->highbit);
+                       mapunit, BITS_PER_U64, e->highbit);
                 goto bad;
         }
 
@@ -446,3 +448,78 @@ bad:
         ebitmap_destroy(e);
         goto out;
 }
+
+int ebitmap_write(struct ebitmap *e, void *fp)
+{
+        struct ebitmap_node *n;
+        u32 count;
+        __le32 buf[3];
+        u64 map;
+        int bit, last_bit, last_startbit, rc;
+
+        buf[0] = cpu_to_le32(BITS_PER_U64);
+
+        count = 0;
+        last_bit = 0;
+        last_startbit = -1;
+        ebitmap_for_each_positive_bit(e, n, bit) {
+                if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
+                        count++;
+                        last_startbit = rounddown(bit, BITS_PER_U64);
+                }
+                last_bit = roundup(bit + 1, BITS_PER_U64);
+        }
+        buf[1] = cpu_to_le32(last_bit);
+        buf[2] = cpu_to_le32(count);
+
+        rc = put_entry(buf, sizeof(u32), 3, fp);
+        if (rc)
+                return rc;
+
+        map = 0;
+        last_startbit = INT_MIN;
+        ebitmap_for_each_positive_bit(e, n, bit) {
+                if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
+                        __le64 buf64[1];
+
+                        /* this is the very first bit */
+                        if (!map) {
+                                last_startbit = rounddown(bit, BITS_PER_U64);
+                                map = (u64)1 << (bit - last_startbit);
+                                continue;
+                        }
+
+                        /* write the last node */
+                        buf[0] = cpu_to_le32(last_startbit);
+                        rc = put_entry(buf, sizeof(u32), 1, fp);
+                        if (rc)
+                                return rc;
+
+                        buf64[0] = cpu_to_le64(map);
+                        rc = put_entry(buf64, sizeof(u64), 1, fp);
+                        if (rc)
+                                return rc;
+
+                        /* set up for the next node */
+                        map = 0;
+                        last_startbit = rounddown(bit, BITS_PER_U64);
+                }
+                map |= (u64)1 << (bit - last_startbit);
+        }
+        /* write the last node */
+        if (map) {
+                __le64 buf64[1];
+
+                /* write the last node */
+                buf[0] = cpu_to_le32(last_startbit);
+                rc = put_entry(buf, sizeof(u32), 1, fp);
+                if (rc)
+                        return rc;
+
+                buf64[0] = cpu_to_le64(map);
+                rc = put_entry(buf64, sizeof(u64), 1, fp);
+                if (rc)
+                        return rc;
+        }
+        return 0;
+}