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Fix argv injection in _create_user and gpasswd loop #4473

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Merged
svartkanin merged 2 commits into from
Apr 26, 2026
+19 −27
Merged

Fix argv injection in _create_user and gpasswd loop #4473

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53b9be2
Fix argv injection in _create_user and gpasswd loop
Softer Apr 24, 2026
6eb8f2b
Extract _chroot_argv helper and harden user/file ops
Softer Apr 26, 2026
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46 changes: 19 additions & 27 deletions archinstall/lib/installer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -739,6 +739,9 @@ def arch_chroot(self, cmd: str, run_as: str | None = None, peek_output: bool = F

return self.run_command(cmd, peek_output=peek_output)

def _chroot_argv(self, *args: str) -> list[str]:
return ['arch-chroot', '-S', str(self.target), *args]

def drop_to_shell(self) -> None:
subprocess.check_call(f'arch-chroot {self.target}', shell=True)

Expand Down Expand Up @@ -987,17 +990,7 @@ def setup_btrfs_snapshot(
}

for config_name, mountpoint in snapper.items():
command = [
'arch-chroot',
'-S',
str(self.target),
'snapper',
'--no-dbus',
'-c',
config_name,
'create-config',
mountpoint,
]
command = self._chroot_argv('snapper', '--no-dbus', '-c', config_name, 'create-config', mountpoint)

try:
SysCommand(command, peek_output=True)
Expand Down Expand Up @@ -1336,13 +1329,7 @@ def _add_grub_bootloader(

boot_dir = Path('/boot')

command = [
'arch-chroot',
'-S',
str(self.target),
'grub-install',
'--debug',
]
command = self._chroot_argv('grub-install', '--debug')

if SysInfo.has_uefi():
if not efi_partition:
Expand Down Expand Up @@ -1922,16 +1909,17 @@ def _create_user(self, user: User) -> None:
if not handled_by_plugin:
info(f'Creating user {user.username}')

cmd = 'useradd -m'
cmd = self._chroot_argv('useradd', '-m')

if user.sudo:
cmd += ' -G wheel'
cmd += ['-G', 'wheel']

cmd += f' {user.username}'
cmd += ['--', user.username]

try:
self.arch_chroot(cmd)
except SysCallError as err:
run(cmd)
except CalledProcessError as err:
debug(f'Error creating user {user.username}: {err}')
raise SystemError(f'Could not create user inside installation: {err}')

for plugin in plugins.values():
Expand All @@ -1942,7 +1930,11 @@ def _create_user(self, user: User) -> None:
self.set_user_password(user)

for group in user.groups:
self.arch_chroot(f'gpasswd -a {user.username} {group}')
cmd = self._chroot_argv('gpasswd', '-a', user.username, group)
try:
run(cmd)
except CalledProcessError as err:
warn(f'Failed to add {user.username} to group {group}: {err}')

if user.sudo:
self.enable_sudo(user)
Expand All @@ -1957,7 +1949,7 @@ def set_user_password(self, user: User) -> bool:
return False

input_data = f'{user.username}:{enc_password}'.encode()
cmd = ['arch-chroot', '-S', str(self.target), 'chpasswd', '--encrypted']
cmd = self._chroot_argv('chpasswd', '--encrypted')

try:
run(cmd, input_data=input_data)
Expand All @@ -1969,7 +1961,7 @@ def set_user_password(self, user: User) -> bool:
def user_set_shell(self, user: str, shell: str) -> bool:
info(f'Setting shell for {user} to {shell}')

cmd = ['arch-chroot', '-S', str(self.target), 'chsh', '-s', shell, user]
cmd = self._chroot_argv('chsh', '-s', shell, user)
try:
run(cmd)
return True
Expand All @@ -1979,7 +1971,7 @@ def user_set_shell(self, user: str, shell: str) -> bool:

def chown(self, owner: str, path: str, options: list[str] | None = None) -> bool:
options = options or []
cmd = ['arch-chroot', '-S', str(self.target), 'chown', *options, owner, path]
cmd = self._chroot_argv('chown', *options, '--', owner, path)
try:
run(cmd)
return True
Expand Down