diff options
Diffstat (limited to 'security/selinux/ss/context.h')
| -rw-r--r-- | security/selinux/ss/context.h | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/security/selinux/ss/context.h b/security/selinux/ss/context.h new file mode 100644 index 000000000..1f59468c0 --- /dev/null +++ b/security/selinux/ss/context.h @@ -0,0 +1,201 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * A security context is a set of security attributes + * associated with each subject and object controlled + * by the security policy. Security contexts are + * externally represented as variable-length strings + * that can be interpreted by a user or application + * with an understanding of the security policy. + * Internally, the security server uses a simple + * structure. This structure is private to the + * security server and can be changed without affecting + * clients of the security server. + * + * Author : Stephen Smalley, <stephen.smalley.work@gmail.com> + */ +#ifndef _SS_CONTEXT_H_ +#define _SS_CONTEXT_H_ + +#include "ebitmap.h" +#include "mls_types.h" +#include "security.h" + +/* + * A security context consists of an authenticated user + * identity, a role, a type and a MLS range. + */ +struct context { + u32 user; + u32 role; + u32 type; + u32 len; /* length of string in bytes */ + struct mls_range range; + char *str; /* string representation if context cannot be mapped. */ +}; + +static inline void mls_context_init(struct context *c) +{ + memset(&c->range, 0, sizeof(c->range)); +} + +static inline int mls_context_cpy(struct context *dst, const struct context *src) +{ + int rc; + + dst->range.level[0].sens = src->range.level[0].sens; + rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat); + if (rc) + goto out; + + dst->range.level[1].sens = src->range.level[1].sens; + rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[1].cat); + if (rc) + ebitmap_destroy(&dst->range.level[0].cat); +out: + return rc; +} + +/* + * Sets both levels in the MLS range of 'dst' to the low level of 'src'. + */ +static inline int mls_context_cpy_low(struct context *dst, const struct context *src) +{ + int rc; + + dst->range.level[0].sens = src->range.level[0].sens; + rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat); + if (rc) + goto out; + + dst->range.level[1].sens = src->range.level[0].sens; + rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[0].cat); + if (rc) + ebitmap_destroy(&dst->range.level[0].cat); +out: + return rc; +} + +/* + * Sets both levels in the MLS range of 'dst' to the high level of 'src'. + */ +static inline int mls_context_cpy_high(struct context *dst, const struct context *src) +{ + int rc; + + dst->range.level[0].sens = src->range.level[1].sens; + rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[1].cat); + if (rc) + goto out; + + dst->range.level[1].sens = src->range.level[1].sens; + rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[1].cat); + if (rc) + ebitmap_destroy(&dst->range.level[0].cat); +out: + return rc; +} + + +static inline int mls_context_glblub(struct context *dst, + const struct context *c1, const struct context *c2) +{ + struct mls_range *dr = &dst->range; + const struct mls_range *r1 = &c1->range, *r2 = &c2->range; + int rc = 0; + + if (r1->level[1].sens < r2->level[0].sens || + r2->level[1].sens < r1->level[0].sens) + /* These ranges have no common sensitivities */ + return -EINVAL; + + /* Take the greatest of the low */ + dr->level[0].sens = max(r1->level[0].sens, r2->level[0].sens); + + /* Take the least of the high */ + dr->level[1].sens = min(r1->level[1].sens, r2->level[1].sens); + + rc = ebitmap_and(&dr->level[0].cat, + &r1->level[0].cat, &r2->level[0].cat); + if (rc) + goto out; + + rc = ebitmap_and(&dr->level[1].cat, + &r1->level[1].cat, &r2->level[1].cat); + if (rc) + goto out; + +out: + return rc; +} + +static inline int mls_context_cmp(const struct context *c1, const struct context *c2) +{ + return ((c1->range.level[0].sens == c2->range.level[0].sens) && + ebitmap_cmp(&c1->range.level[0].cat, &c2->range.level[0].cat) && + (c1->range.level[1].sens == c2->range.level[1].sens) && + ebitmap_cmp(&c1->range.level[1].cat, &c2->range.level[1].cat)); +} + +static inline void mls_context_destroy(struct context *c) +{ + ebitmap_destroy(&c->range.level[0].cat); + ebitmap_destroy(&c->range.level[1].cat); + mls_context_init(c); +} + +static inline void context_init(struct context *c) +{ + memset(c, 0, sizeof(*c)); +} + +static inline int context_cpy(struct context *dst, const struct context *src) +{ + int rc; + + dst->user = src->user; + dst->role = src->role; + dst->type = src->type; + if (src->str) { + dst->str = kstrdup(src->str, GFP_ATOMIC); + if (!dst->str) + return -ENOMEM; + dst->len = src->len; + } else { + dst->str = NULL; + dst->len = 0; + } + rc = mls_context_cpy(dst, src); + if (rc) { + kfree(dst->str); + dst->str = NULL; + dst->len = 0; + return rc; + } + return 0; +} + +static inline void context_destroy(struct context *c) +{ + c->user = c->role = c->type = 0; + kfree(c->str); + c->str = NULL; + c->len = 0; + mls_context_destroy(c); +} + +static inline int context_cmp(const struct context *c1, const struct context *c2) +{ + if (c1->len && c2->len) + return (c1->len == c2->len && !strcmp(c1->str, c2->str)); + if (c1->len || c2->len) + return 0; + return ((c1->user == c2->user) && + (c1->role == c2->role) && + (c1->type == c2->type) && + mls_context_cmp(c1, c2)); +} + +u32 context_compute_hash(const struct context *c); + +#endif /* _SS_CONTEXT_H_ */ + |