src/basic/capability-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   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_t) -1
  14
  15 unsigned long cap_last_cap(void);
  16 int have_effective_cap(int value);
  17 int capability_bounding_set_drop(uint64_t keep, bool right_now);
  18 int capability_bounding_set_drop_usermode(uint64_t keep);
  19
  20 int capability_ambient_set_apply(uint64_t set, bool also_inherit);
  21 int capability_update_inherited_set(cap_t caps, uint64_t ambient_set);
  22
  23 int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilities);
  24
  25 int drop_capability(cap_value_t cv);
  26
  27 DEFINE_TRIVIAL_CLEANUP_FUNC(cap_t, cap_free);
  28 #define _cleanup_cap_free_ _cleanup_(cap_freep)
  29
  30 static inline void cap_free_charpp(char **p) {
  31         if (*p)
  32                 cap_free(*p);
  33 }
  34 #define _cleanup_cap_free_charp_ _cleanup_(cap_free_charpp)
  35
  36 static inline bool cap_test_all(uint64_t caps) {
  37         uint64_t m;
  38         m = (UINT64_C(1) << (cap_last_cap() + 1)) - 1;
  39         return FLAGS_SET(caps, m);
  40 }
  41
  42 bool ambient_capabilities_supported(void);
  43
  44 /* Identical to linux/capability.h's CAP_TO_MASK(), but uses an unsigned 1U instead of a signed 1 for shifting left, in
  45  * order to avoid complaints about shifting a signed int left by 31 bits, which would make it negative. */
  46 #define CAP_TO_MASK_CORRECTED(x) (1U << ((x) & 31U))
  47
  48 typedef struct CapabilityQuintet {
  49         /* Stores all five types of capabilities in one go. Note that we use (uint64_t) -1 for unset here. This hence
  50          * needs to be updated as soon as Linux learns more than 63 caps. */
  51         uint64_t effective;
  52         uint64_t bounding;
  53         uint64_t inheritable;
  54         uint64_t permitted;
  55         uint64_t ambient;
  56 } CapabilityQuintet;
  57
  58 assert_cc(CAP_LAST_CAP < 64);
  59
  60 #define CAPABILITY_QUINTET_NULL { (uint64_t) -1, (uint64_t) -1, (uint64_t) -1, (uint64_t) -1, (uint64_t) -1 }
  61
  62 static inline bool capability_quintet_is_set(const CapabilityQuintet *q) {
  63         return q->effective != (uint64_t) -1 ||
  64                 q->bounding != (uint64_t) -1 ||
  65                 q->inheritable != (uint64_t) -1 ||
  66                 q->permitted != (uint64_t) -1 ||
  67                 q->ambient != (uint64_t) -1;
  68 }
  69
  70 int capability_quintet_enforce(const CapabilityQuintet *q);