controller-legacy/src/helpers/drop_privileges.c

81 lines
1.7 KiB
C

#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <config.h>
#include <logger.h>
static uid_t
get_uid_for_user(char *user)
{
if(user == NULL || user[0] == '\0')
{
return getuid();
}
struct passwd *pwd = calloc(1, sizeof(struct passwd));
size_t buffer_len = sysconf(_SC_GETPW_R_SIZE_MAX) * sizeof(char);
char *buffer = malloc(buffer_len);
getpwnam_r(user, pwd, buffer, buffer_len, &pwd);
if(pwd == NULL)
{
LOGGER_CRIT("couldn't find user to drop privileges\n");
exit(1);
}
uid_t result = pwd->pw_uid;
free(buffer);
free(pwd);
return result;
}
static gid_t
get_gid_for_group(char *group)
{
if(group == NULL || group[0] == '\0')
{
return getgid();
}
struct group *grp = calloc(1, sizeof(struct group));
size_t buffer_len = sysconf(_SC_GETPW_R_SIZE_MAX) * sizeof(char);
char *buffer = malloc(buffer_len);
getgrnam_r(group, grp, buffer, buffer_len, &grp);
if(grp == NULL)
{
LOGGER_CRIT("couldn't find group to drop privileges\n");
exit(1);
}
gid_t result = grp->gr_gid;
free(buffer);
free(grp);
return result;
}
int
helper_drop_privileges()
{
uid_t uid = get_uid_for_user(global_config.user);
gid_t gid = get_gid_for_group(global_config.group);
LOGGER_DEBUG("drop privileges to %lu:%lu\n", uid, gid);
if (setgid(gid) == -1)
{
LOGGER_CRIT("failed to drop group privileges\n");
exit(1);
}
if (setuid(uid) == -1)
{
LOGGER_CRIT("failed to drop user privileges\n");
exit(1);
}
return 0;
}