1 // SPDX-License-Identifier: GPL-2.0
2 #include "cap_helpers.h"
3
4 /* Avoid including <sys/capability.h> from the libcap-devel package,
5 * so directly declare them here and use them from glibc.
6 */
7 int capget(cap_user_header_t header, cap_user_data_t data);
8 int capset(cap_user_header_t header, const cap_user_data_t data);
9
cap_enable_effective(__u64 caps,__u64 * old_caps)10 int cap_enable_effective(__u64 caps, __u64 *old_caps)
11 {
12 struct __user_cap_data_struct data[_LINUX_CAPABILITY_U32S_3];
13 struct __user_cap_header_struct hdr = {
14 .version = _LINUX_CAPABILITY_VERSION_3,
15 };
16 __u32 cap0 = caps;
17 __u32 cap1 = caps >> 32;
18 int err;
19
20 err = capget(&hdr, data);
21 if (err)
22 return err;
23
24 if (old_caps)
25 *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective;
26
27 if ((data[0].effective & cap0) == cap0 &&
28 (data[1].effective & cap1) == cap1)
29 return 0;
30
31 data[0].effective |= cap0;
32 data[1].effective |= cap1;
33 err = capset(&hdr, data);
34 if (err)
35 return err;
36
37 return 0;
38 }
39
cap_disable_effective(__u64 caps,__u64 * old_caps)40 int cap_disable_effective(__u64 caps, __u64 *old_caps)
41 {
42 struct __user_cap_data_struct data[_LINUX_CAPABILITY_U32S_3];
43 struct __user_cap_header_struct hdr = {
44 .version = _LINUX_CAPABILITY_VERSION_3,
45 };
46 __u32 cap0 = caps;
47 __u32 cap1 = caps >> 32;
48 int err;
49
50 err = capget(&hdr, data);
51 if (err)
52 return err;
53
54 if (old_caps)
55 *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective;
56
57 if (!(data[0].effective & cap0) && !(data[1].effective & cap1))
58 return 0;
59
60 data[0].effective &= ~cap0;
61 data[1].effective &= ~cap1;
62 err = capset(&hdr, data);
63 if (err)
64 return err;
65
66 return 0;
67 }
68