1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2 #pragma once
3
4 #include <stdbool.h>
5 #include <stdint.h>
6 #include <sys/capability.h>
7 #include <sys/types.h>
8
9 #include "macro.h"
10 #include "missing_capability.h"
11 #include "util.h"
12
13 #define CAP_ALL UINT64_MAX
14
15 unsigned cap_last_cap(void);
16 int have_effective_cap(int value);
17 int capability_gain_cap_setpcap(cap_t *return_caps);
18 int capability_bounding_set_drop(uint64_t keep, bool right_now);
19 int capability_bounding_set_drop_usermode(uint64_t keep);
20
21 int capability_ambient_set_apply(uint64_t set, bool also_inherit);
22 int capability_update_inherited_set(cap_t caps, uint64_t ambient_set);
23
24 int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilities);
25
26 int drop_capability(cap_value_t cv);
27
28 DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(cap_t, cap_free, NULL);
29 #define _cleanup_cap_free_ _cleanup_(cap_freep)
30
cap_free_charpp(char ** p)31 static inline void cap_free_charpp(char **p) {
32 if (*p)
33 cap_free(*p);
34 }
35 #define _cleanup_cap_free_charp_ _cleanup_(cap_free_charpp)
36
all_capabilities(void)37 static inline uint64_t all_capabilities(void) {
38 return UINT64_MAX >> (63 - cap_last_cap());
39 }
40
cap_test_all(uint64_t caps)41 static inline bool cap_test_all(uint64_t caps) {
42 return FLAGS_SET(caps, all_capabilities());
43 }
44
45 bool ambient_capabilities_supported(void);
46
47 /* Identical to linux/capability.h's CAP_TO_MASK(), but uses an unsigned 1U instead of a signed 1 for shifting left, in
48 * order to avoid complaints about shifting a signed int left by 31 bits, which would make it negative. */
49 #define CAP_TO_MASK_CORRECTED(x) (1U << ((x) & 31U))
50
51 typedef struct CapabilityQuintet {
52 /* Stores all five types of capabilities in one go. Note that we use UINT64_MAX for unset here. This hence
53 * needs to be updated as soon as Linux learns more than 63 caps. */
54 uint64_t effective;
55 uint64_t bounding;
56 uint64_t inheritable;
57 uint64_t permitted;
58 uint64_t ambient;
59 } CapabilityQuintet;
60
61 assert_cc(CAP_LAST_CAP < 64);
62
63 #define CAPABILITY_QUINTET_NULL { UINT64_MAX, UINT64_MAX, UINT64_MAX, UINT64_MAX, UINT64_MAX }
64
capability_quintet_is_set(const CapabilityQuintet * q)65 static inline bool capability_quintet_is_set(const CapabilityQuintet *q) {
66 return q->effective != UINT64_MAX ||
67 q->bounding != UINT64_MAX ||
68 q->inheritable != UINT64_MAX ||
69 q->permitted != UINT64_MAX ||
70 q->ambient != UINT64_MAX;
71 }
72
73 /* Mangles the specified caps quintet taking the current bounding set into account:
74 * drops all caps from all five sets if our bounding set doesn't allow them.
75 * Returns true if the quintet was modified. */
76 bool capability_quintet_mangle(CapabilityQuintet *q);
77
78 int capability_quintet_enforce(const CapabilityQuintet *q);
79