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 */ 26struct 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 35static inline void mls_context_init(struct context *c) 36{ 37 memset(&c->range, 0, sizeof(c->range)); 38} 39 40static 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); 53out: 54 return rc; 55} 56 57/* 58 * Sets both levels in the MLS range of 'dst' to the low level of 'src'. 59 */ 60static 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); 73out: 74 return rc; 75} 76 77static 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 85static 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 92static inline void context_init(struct context *c) 93{ 94 memset(c, 0, sizeof(*c)); 95} 96 97static 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 121static 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 130static 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