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 u32 len; /* length of string in bytes */
31 struct mls_range range;
32 char *str; /* string representation if context cannot be mapped. */
33 };
34
mls_context_init(struct context * c)35 static inline void mls_context_init(struct context *c)
36 {
37 memset(&c->range, 0, sizeof(c->range));
38 }
39
mls_context_cpy(struct context * dst,struct context * src)40 static inline int mls_context_cpy(struct context *dst, struct context *src)
41 {
42 int rc;
43
44 dst->range.level[0].sens = src->range.level[0].sens;
45 rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
46 if (rc)
47 goto out;
48
49 dst->range.level[1].sens = src->range.level[1].sens;
50 rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[1].cat);
51 if (rc)
52 ebitmap_destroy(&dst->range.level[0].cat);
53 out:
54 return rc;
55 }
56
57 /*
58 * Sets both levels in the MLS range of 'dst' to the low level of 'src'.
59 */
mls_context_cpy_low(struct context * dst,struct context * src)60 static inline int mls_context_cpy_low(struct context *dst, struct context *src)
61 {
62 int rc;
63
64 dst->range.level[0].sens = src->range.level[0].sens;
65 rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
66 if (rc)
67 goto out;
68
69 dst->range.level[1].sens = src->range.level[0].sens;
70 rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[0].cat);
71 if (rc)
72 ebitmap_destroy(&dst->range.level[0].cat);
73 out:
74 return rc;
75 }
76
mls_context_cmp(struct context * c1,struct context * c2)77 static inline int mls_context_cmp(struct context *c1, struct context *c2)
78 {
79 return ((c1->range.level[0].sens == c2->range.level[0].sens) &&
80 ebitmap_cmp(&c1->range.level[0].cat, &c2->range.level[0].cat) &&
81 (c1->range.level[1].sens == c2->range.level[1].sens) &&
82 ebitmap_cmp(&c1->range.level[1].cat, &c2->range.level[1].cat));
83 }
84
mls_context_destroy(struct context * c)85 static inline void mls_context_destroy(struct context *c)
86 {
87 ebitmap_destroy(&c->range.level[0].cat);
88 ebitmap_destroy(&c->range.level[1].cat);
89 mls_context_init(c);
90 }
91
context_init(struct context * c)92 static inline void context_init(struct context *c)
93 {
94 memset(c, 0, sizeof(*c));
95 }
96
context_cpy(struct context * dst,struct context * src)97 static inline int context_cpy(struct context *dst, struct context *src)
98 {
99 int rc;
100
101 dst->user = src->user;
102 dst->role = src->role;
103 dst->type = src->type;
104 if (src->str) {
105 dst->str = kstrdup(src->str, GFP_ATOMIC);
106 if (!dst->str)
107 return -ENOMEM;
108 dst->len = src->len;
109 } else {
110 dst->str = NULL;
111 dst->len = 0;
112 }
113 rc = mls_context_cpy(dst, src);
114 if (rc) {
115 kfree(dst->str);
116 return rc;
117 }
118 return 0;
119 }
120
context_destroy(struct context * c)121 static inline void context_destroy(struct context *c)
122 {
123 c->user = c->role = c->type = 0;
124 kfree(c->str);
125 c->str = NULL;
126 c->len = 0;
127 mls_context_destroy(c);
128 }
129
context_cmp(struct context * c1,struct context * c2)130 static inline int context_cmp(struct context *c1, struct context *c2)
131 {
132 if (c1->len && c2->len)
133 return (c1->len == c2->len && !strcmp(c1->str, c2->str));
134 if (c1->len || c2->len)
135 return 0;
136 return ((c1->user == c2->user) &&
137 (c1->role == c2->role) &&
138 (c1->type == c2->type) &&
139 mls_context_cmp(c1, c2));
140 }
141
142 #endif /* _SS_CONTEXT_H_ */
143
144