cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

cap_helpers.c (1539B)

      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 */
      7int capget(cap_user_header_t header, cap_user_data_t data);
      8int capset(cap_user_header_t header, const cap_user_data_t data);
      9
     10int 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
     40int 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}