security/selinux/ss/context.h

   1 /*
   2  * A security context is a set of security attributes
   3  * associated with each subject and object controlled
   4  * by the security policy.  Security contexts are
   5   * externally represented as variable-length strings
   6  * that can be interpreted by a user or application
   7  * with an understanding of the security policy.
   8  * Internally, the security server uses a simple
   9  * structure.  This structure is private to the
  10  * security server and can be changed without affecting
  11  * clients of the security server.
  12  *
  13  * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
  14  */
  15 #ifndef _SS_CONTEXT_H_
  16 #define _SS_CONTEXT_H_
  17
  18 #include "ebitmap.h"
  19 #include "mls_types.h"
  20 #include "security.h"
  21
  22 /*
  23  * A security context consists of an authenticated user
  24  * identity, a role, a type and a MLS range.
  25  */
  26 struct context {
  27         u32 user;
  28         u32 role;
  29         u32 type;
  30         struct mls_range range;
  31 };
  32
  33 static inline void mls_context_init(struct context *c)
  34 {
  35         memset(&c->range, 0, sizeof(c->range));
  36 }
  37
  38 static inline int mls_context_cpy(struct context *dst, struct context *src)
  39 {
  40         int rc;
  41
  42         if (!selinux_mls_enabled)
  43                 return 0;
  44
  45         dst->range.level[0].sens = src->range.level[0].sens;
  46         rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
  47         if (rc)
  48                 goto out;
  49
  50         dst->range.level[1].sens = src->range.level[1].sens;
  51         rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[1].cat);
  52         if (rc)
  53                 ebitmap_destroy(&dst->range.level[0].cat);
  54 out:
  55         return rc;
  56 }
  57
  58 /*
  59  * Sets both levels in the MLS range of 'dst' to the low level of 'src'.
  60  */
  61 static inline int mls_context_cpy_low(struct context *dst, struct context *src)
  62 {
  63         int rc;
  64
  65         if (!selinux_mls_enabled)
  66                 return 0;
  67
  68         dst->range.level[0].sens = src->range.level[0].sens;
  69         rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
  70         if (rc)
  71                 goto out;
  72
  73         dst->range.level[1].sens = src->range.level[0].sens;
  74         rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[0].cat);
  75         if (rc)
  76                 ebitmap_destroy(&dst->range.level[0].cat);
  77 out:
  78         return rc;
  79 }
  80
  81 static inline int mls_context_cmp(struct context *c1, struct context *c2)
  82 {
  83         if (!selinux_mls_enabled)
  84                 return 1;
  85
  86         return ((c1->range.level[0].sens == c2->range.level[0].sens) &&
  87                 ebitmap_cmp(&c1->range.level[0].cat,&c2->range.level[0].cat) &&
  88                 (c1->range.level[1].sens == c2->range.level[1].sens) &&
  89                 ebitmap_cmp(&c1->range.level[1].cat,&c2->range.level[1].cat));
  90 }
  91
  92 static inline void mls_context_destroy(struct context *c)
  93 {
  94         if (!selinux_mls_enabled)
  95                 return;
  96
  97         ebitmap_destroy(&c->range.level[0].cat);
  98         ebitmap_destroy(&c->range.level[1].cat);
  99         mls_context_init(c);
 100 }
 101
 102 static inline void context_init(struct context *c)
 103 {
 104         memset(c, 0, sizeof(*c));
 105 }
 106
 107 static inline int context_cpy(struct context *dst, struct context *src)
 108 {
 109         dst->user = src->user;
 110         dst->role = src->role;
 111         dst->type = src->type;
 112         return mls_context_cpy(dst, src);
 113 }
 114
 115 static inline void context_destroy(struct context *c)
 116 {
 117         c->user = c->role = c->type = 0;
 118         mls_context_destroy(c);
 119 }
 120
 121 static inline int context_cmp(struct context *c1, struct context *c2)
 122 {
 123         return ((c1->user == c2->user) &&
 124                 (c1->role == c2->role) &&
 125                 (c1->type == c2->type) &&
 126                 mls_context_cmp(c1, c2));
 127 }
 128
 129 #endif  /* _SS_CONTEXT_H_ */
 130