1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * A security context is a set of security attributes 4 * associated with each subject and object controlled 5 * by the security policy. Security contexts are 6 * externally represented as variable-length strings 7 * that can be interpreted by a user or application 8 * with an understanding of the security policy. 9 * Internally, the security server uses a simple 10 * structure. This structure is private to the 11 * security server and can be changed without affecting 12 * clients of the security server. 13 * 14 * Author : Stephen Smalley, <sds@tycho.nsa.gov> 15 */ 16 #ifndef _SS_CONTEXT_H_ 17 #define _SS_CONTEXT_H_ 18 19 #include "ebitmap.h" 20 #include "mls_types.h" 21 #include "security.h" 22 23 /* 24 * A security context consists of an authenticated user 25 * identity, a role, a type and a MLS range. 26 */ 27 struct context { 28 u32 user; 29 u32 role; 30 u32 type; 31 u32 len; /* length of string in bytes */ 32 struct mls_range range; 33 char *str; /* string representation if context cannot be mapped. */ 34 }; 35 36 static inline void mls_context_init(struct context *c) 37 { 38 memset(&c->range, 0, sizeof(c->range)); 39 } 40 41 static inline int mls_context_cpy(struct context *dst, struct context *src) 42 { 43 int rc; 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 dst->range.level[0].sens = src->range.level[0].sens; 66 rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat); 67 if (rc) 68 goto out; 69 70 dst->range.level[1].sens = src->range.level[0].sens; 71 rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[0].cat); 72 if (rc) 73 ebitmap_destroy(&dst->range.level[0].cat); 74 out: 75 return rc; 76 } 77 78 /* 79 * Sets both levels in the MLS range of 'dst' to the high level of 'src'. 80 */ 81 static inline int mls_context_cpy_high(struct context *dst, struct context *src) 82 { 83 int rc; 84 85 dst->range.level[0].sens = src->range.level[1].sens; 86 rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[1].cat); 87 if (rc) 88 goto out; 89 90 dst->range.level[1].sens = src->range.level[1].sens; 91 rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[1].cat); 92 if (rc) 93 ebitmap_destroy(&dst->range.level[0].cat); 94 out: 95 return rc; 96 } 97 98 static inline int mls_context_cmp(struct context *c1, struct context *c2) 99 { 100 return ((c1->range.level[0].sens == c2->range.level[0].sens) && 101 ebitmap_cmp(&c1->range.level[0].cat, &c2->range.level[0].cat) && 102 (c1->range.level[1].sens == c2->range.level[1].sens) && 103 ebitmap_cmp(&c1->range.level[1].cat, &c2->range.level[1].cat)); 104 } 105 106 static inline void mls_context_destroy(struct context *c) 107 { 108 ebitmap_destroy(&c->range.level[0].cat); 109 ebitmap_destroy(&c->range.level[1].cat); 110 mls_context_init(c); 111 } 112 113 static inline void context_init(struct context *c) 114 { 115 memset(c, 0, sizeof(*c)); 116 } 117 118 static inline int context_cpy(struct context *dst, struct context *src) 119 { 120 int rc; 121 122 dst->user = src->user; 123 dst->role = src->role; 124 dst->type = src->type; 125 if (src->str) { 126 dst->str = kstrdup(src->str, GFP_ATOMIC); 127 if (!dst->str) 128 return -ENOMEM; 129 dst->len = src->len; 130 } else { 131 dst->str = NULL; 132 dst->len = 0; 133 } 134 rc = mls_context_cpy(dst, src); 135 if (rc) { 136 kfree(dst->str); 137 return rc; 138 } 139 return 0; 140 } 141 142 static inline void context_destroy(struct context *c) 143 { 144 c->user = c->role = c->type = 0; 145 kfree(c->str); 146 c->str = NULL; 147 c->len = 0; 148 mls_context_destroy(c); 149 } 150 151 static inline int context_cmp(struct context *c1, struct context *c2) 152 { 153 if (c1->len && c2->len) 154 return (c1->len == c2->len && !strcmp(c1->str, c2->str)); 155 if (c1->len || c2->len) 156 return 0; 157 return ((c1->user == c2->user) && 158 (c1->role == c2->role) && 159 (c1->type == c2->type) && 160 mls_context_cmp(c1, c2)); 161 } 162 163 #endif /* _SS_CONTEXT_H_ */ 164 165