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adding initial version

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tengel 2024-03-20 09:30:28 -05:00
parent 84230329cc
commit e52e95905d
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/*
limitcheck.c - given a user, drop privileges and check ulimits
Compile: gcc -o limitcheck limitcheck.c
Use: sudo ./limitcheck <user>
Author: Troy Engel
License: APL 2.0
*/
#include <sys/types.h>
#include <sys/resource.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>
static int drop_privileges(const char *user) {
struct passwd *pw = NULL;
pw = getpwnam(user);
if (pw) {
if (initgroups(pw->pw_name, pw->pw_gid) != 0 ||
setgid(pw->pw_gid) != 0 || setuid(pw->pw_uid) != 0) {
fprintf(stdout, "Couldn't change to '%.32s' uid=%lu gid=%lu\n",
user, (unsigned long)pw->pw_uid, (unsigned long)pw->pw_gid);
return 1;
} else {
fprintf(stdout, "Successfully changed to '%.32s' uid=%lu gid=%lu\n",
user, (unsigned long)pw->pw_uid, (unsigned long)pw->pw_gid);
return 0;
}
} else {
fprintf(stdout, "Couldn't find user '%.32s'\n", user);
return 1;
}
}
static void print_limits() {
struct rlimit rl;
fprintf(stdout, " %11s %11s\n", "soft", "hard");
getrlimit(RLIMIT_CORE, &rl);
fprintf(stdout, "core file size: %11d %11d\n", (long long int)rl.rlim_cur,
(long long int)rl.rlim_max);
getrlimit(RLIMIT_CPU, &rl);
fprintf(stdout, "cpu time: %11d %11d\n", (long long int)rl.rlim_cur,
(long long int)rl.rlim_max);
getrlimit(RLIMIT_DATA, &rl);
fprintf(stdout, "data seg size: %11d %11d\n", (long long int)rl.rlim_cur,
(long long int)rl.rlim_max);
getrlimit(RLIMIT_FSIZE, &rl);
fprintf(stdout, "file size: %11d %11d\n", (long long int)rl.rlim_cur,
(long long int)rl.rlim_max);
getrlimit(RLIMIT_NOFILE, &rl);
fprintf(stdout, "open files: %11d %11d\n", (long long int)rl.rlim_cur,
(long long int)rl.rlim_max);
getrlimit(RLIMIT_STACK, &rl);
fprintf(stdout, "stack size: %11d %11d\n", (long long int)rl.rlim_cur,
(long long int)rl.rlim_max);
getrlimit(RLIMIT_AS, &rl);
fprintf(stdout, "memory size: %11d %11d\n", (long long int)rl.rlim_cur,
(long long int)rl.rlim_max);
}
int main(int argc, char **argv) {
/* we only accept one argument - the user to check */
if (argc == 2) {
if (drop_privileges(argv[1]) == 0) {
print_limits();
return 0;
} else {
return 1;
}
} else {
fprintf(stdout, "Usage: %s <name of system user>\n", argv[0]);
return 1;
}
}