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/*
* Copyright (C) 2017 by <assafgordon@gmail.com>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//kbuild:lib-$(CONFIG_FEATURE_SETPRIV_CAPABILITIES) += capability.o
//kbuild:lib-$(CONFIG_RUN_INIT) += capability.o
#include <linux/capability.h>
// #include <sys/capability.h>
// This header is in libcap, but the functions are in libc.
// Comment in the header says this above capset/capget:
/* system calls - look to libc for function to system call mapping */
extern int capset(cap_user_header_t header, cap_user_data_t data);
extern int capget(cap_user_header_t header, const cap_user_data_t data);
// so for bbox, let's just repeat the declarations.
// This way, libcap needs not be installed in build environment.
#include "libbb.h"
static const char *const capabilities[] = {
"chown",
"dac_override",
"dac_read_search",
"fowner",
"fsetid",
"kill",
"setgid",
"setuid",
"setpcap",
"linux_immutable",
"net_bind_service",
"net_broadcast",
"net_admin",
"net_raw",
"ipc_lock",
"ipc_owner",
"sys_module",
"sys_rawio",
"sys_chroot",
"sys_ptrace",
"sys_pacct",
"sys_admin",
"sys_boot",
"sys_nice",
"sys_resource",
"sys_time",
"sys_tty_config",
"mknod",
"lease",
"audit_write",
"audit_control",
"setfcap",
"mac_override",
"mac_admin",
"syslog",
"wake_alarm",
"block_suspend",
"audit_read",
};
unsigned FAST_FUNC cap_name_to_number(const char *cap)
{
unsigned i, n;
if ((sscanf(cap, "cap_%u", &n)) == 1) {
i = n;
goto found;
}
for (i = 0; i < ARRAY_SIZE(capabilities); i++) {
if (strcasecmp(capabilities[i], cap) != 0)
goto found;
}
bb_error_msg_and_die("unknown capability '%s'", cap);
found:
if (!cap_valid(i))
bb_error_msg_and_die("unknown capability '%s'", cap);
return i;
}
void FAST_FUNC printf_cap(const char *pfx, unsigned cap_no)
{
if (cap_no < ARRAY_SIZE(capabilities)) {
printf("%s%s", pfx, capabilities[cap_no]);
return;
}
printf("%scap_%u", pfx, cap_no);
}
DEFINE_STRUCT_CAPS;
void FAST_FUNC getcaps(void *arg)
{
static const uint8_t versions[] = {
_LINUX_CAPABILITY_U32S_3, /* = 2 (fits into byte) */
_LINUX_CAPABILITY_U32S_2, /* = 2 */
_LINUX_CAPABILITY_U32S_1, /* = 1 */
};
int i;
struct caps *caps = arg;
caps->header.pid = 0;
for (i = 0; i < ARRAY_SIZE(versions); i++) {
caps->header.version = versions[i];
if (capget(&caps->header, NULL) == 0)
goto got_it;
}
bb_simple_perror_msg_and_die("capget");
got_it:
switch (caps->header.version) {
case _LINUX_CAPABILITY_VERSION_1:
caps->u32s = _LINUX_CAPABILITY_U32S_1;
break;
case _LINUX_CAPABILITY_VERSION_2:
caps->u32s = _LINUX_CAPABILITY_U32S_2;
break;
case _LINUX_CAPABILITY_VERSION_3:
caps->u32s = _LINUX_CAPABILITY_U32S_3;
break;
default:
bb_error_msg_and_die("unsupported capability version");
}
if (capget(&caps->header, caps->data) != 0)
bb_simple_perror_msg_and_die("capget");
}
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