diff options
Diffstat (limited to 'python/runner/sandbox.c')
| -rw-r--r-- | python/runner/sandbox.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/python/runner/sandbox.c b/python/runner/sandbox.c new file mode 100644 index 0000000..12e2720 --- /dev/null +++ b/python/runner/sandbox.c @@ -0,0 +1,47 @@ +#include <fcntl.h> +#include <pwd.h> +#include <stdio.h> +#include <sys/prctl.h> +#include <sys/resource.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> + +int main(int argc, char* argv[]) +{ + if (argc < 3) { + fprintf(stderr, "usage: %s USERNAME FILE\n", argv[0]); + return 1; + } + + // switch user (requires root or "setcap cap_setuid,cap_setgid+ep") + char const* username = argv[1]; + struct passwd const* pw = getpwnam(username); + if (!pw) { + fprintf(stderr, "no such user: %s\n", username); + return 1; + } + int ret = 0; + if ((ret = setuid(pw->pw_uid)) != 0) + fprintf(stderr, "setuid returned %d\n", ret); + if ((ret = setgid(pw->pw_gid)) != 0) + fprintf(stderr, "setgid returned %d\n", ret); + + // limit CPU time to 1 second + struct rlimit const cpu_limit = { .rlim_cur = 1, .rlim_max = 1 }; + if ((ret = setrlimit(RLIMIT_CPU, &cpu_limit)) != 0) + fprintf(stderr, "setrlimit(CPU) returned %d\n", ret); + + // don't allow writing files of any size + struct rlimit const fsize_limit = { .rlim_cur = 0, .rlim_max = 0 }; + if ((ret = setrlimit(RLIMIT_FSIZE, &fsize_limit)) != 0) + fprintf(stderr, "setrlimit(FSIZE) returned %d\n", ret); + + // there will be no fork + struct rlimit const nproc_limit = { .rlim_cur = 0, .rlim_max = 0 }; + if ((ret = setrlimit(RLIMIT_NPROC, &nproc_limit)) != 0) + fprintf(stderr, "setrlimit(NPROC) returned %d\n", ret); + + char* const args[] = { argv[2], (char*)0 }; + return execvp(argv[2], args); +} |