RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 13:07:46 +00:00
Code Issues Activity Actions

Userland: chroot: Add --userspec/-u flag to set uid/gid for chroot

Browse source
This commit is contained in:
Brendan Coles 2020-11-14 11:06:49 +00:00 • committed by Andreas Kling
parent 677af891b4
commit f8c980a06b
2 changed files with 46 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

6
Base/usr/share/man/man8/chroot.md
View file

@ -24,6 +24,12 @@ Mount options can be given in the same format as for [`mount`(8)](mount.md).
/ /
``` ```
```sh
# chroot -u 200:200 /var/chroot
$ id
uid=200(nona) gid=200(n/a)
```
## See also ## See also
* [`chroot`(2)](../man2/chroot.md) * [`chroot`(2)](../man2/chroot.md)

43
Userland/chroot.cpp
View file

@ -27,19 +27,40 @@
#include <AK/StringView.h> #include <AK/StringView.h>
#include <LibCore/ArgsParser.h> #include <LibCore/ArgsParser.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h> #include <unistd.h>
int main(int argc, char** argv) int main(int argc, char** argv)
{ {
int flags = -1;
uid_t chroot_user = 0;
gid_t chroot_group = 0;
const char* path = nullptr; const char* path = nullptr;
const char* program = "/bin/Shell"; const char* program = "/bin/Shell";
int flags = -1; const char* userspec = "0:0";
Core::ArgsParser args_parser; Core::ArgsParser args_parser;
args_parser.add_positional_argument(path, "New root directory", "path"); args_parser.add_positional_argument(path, "New root directory", "path");
args_parser.add_positional_argument(program, "Program to run", "program", Core::ArgsParser::Required::No); args_parser.add_positional_argument(program, "Program to run", "program", Core::ArgsParser::Required::No);
Core::ArgsParser::Option option { Core::ArgsParser::Option userspec_option {
true,
"The uid:gid to use",
"userspec",
'u',
"userpec",
[&userspec](const char* s) {
Vector<StringView> parts = StringView(s).split_view(':', true);
if (parts.size() != 2)
return false;
userspec = s;
return true;
}
};
args_parser.add_option(move(userspec_option));
Core::ArgsParser::Option mount_options {
true, true,
"Mount options", "Mount options",
"options", "options",
@ -69,7 +90,7 @@ int main(int argc, char** argv)
return true; return true;
} }
}; };
args_parser.add_option(move(option)); args_parser.add_option(move(mount_options));
args_parser.parse(argc, argv); args_parser.parse(argc, argv);
if (chroot_with_mount_flags(path, flags) < 0) { if (chroot_with_mount_flags(path, flags) < 0) {
@ -82,6 +103,22 @@ int main(int argc, char** argv)
return 1; return 1;
} }
// Failed parsing will silently fail open (uid=0; gid=0);
// 0:0 is also the default when no --userspec argument is provided.
auto parts = String(userspec).split(':', true);
chroot_user = (uid_t)strtol(parts[0].characters(), nullptr, 10);
chroot_group = (uid_t)strtol(parts[1].characters(), nullptr, 10);
if (setresgid(chroot_group, chroot_group, chroot_group)) {
perror("setgid");
return 1;
}
if (setresuid(chroot_user, chroot_user, chroot_user)) {
perror("setuid");
return 1;
}
execl(program, program, nullptr); execl(program, program, nullptr);
perror("execl"); perror("execl");
return 1; return 1;