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Kernel: Forbid access to /sys/kernel/power_state for Jailed processes

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There's simply no benefit in allowing sandboxed programs to change the
power state of the machine, so disallow writes to the mentioned node to
prevent malicious programs to request that.
This commit is contained in:
Liav A 2022-11-11 14:55:28 +02:00 committed by Andrew Kaster
parent 1aa07d7328
commit 2e55956784
1 changed files with 14 additions and 7 deletions
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21
Kernel/FileSystem/SysFS/Subsystems/Kernel/PowerStateSwitch.cpp
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@ -16,6 +16,7 @@
#include <Kernel/Process.h>
#include <Kernel/Sections.h>
#include <Kernel/TTY/ConsoleManagement.h>
#include <Kernel/WorkQueue.h>
namespace Kernel {
@ -45,18 +46,25 @@ ErrorOr<void> SysFSPowerStateSwitchNode::truncate(u64 size)
ErrorOr<size_t> SysFSPowerStateSwitchNode::write_bytes(off_t offset, size_t count, UserOrKernelBuffer const& data, OpenFileDescription*)
{
TRY(Process::current().jail().with([&](auto const& my_jail) -> ErrorOr<void> {
// Note: If we are in a jail, don't let the current process to change the power state.
if (my_jail)
return Error::from_errno(EPERM);
return {};
}));
if (Checked<off_t>::addition_would_overflow(offset, count))
return EOVERFLOW;
return Error::from_errno(EOVERFLOW);
if (offset > 0)
return EINVAL;
return Error::from_errno(EINVAL);
if (count > 1)
return EINVAL;
return Error::from_errno(EINVAL);
char buf[1];
TRY(data.read(buf, 1));
if (buf[0] == '0')
return Error::from_errno(EINVAL);
switch (buf[0]) {
case '0':
return EINVAL;
VERIFY_NOT_REACHED();
case '1':
reboot();
VERIFY_NOT_REACHED();
@ -64,9 +72,8 @@ ErrorOr<size_t> SysFSPowerStateSwitchNode::write_bytes(off_t offset, size_t coun
poweroff();
VERIFY_NOT_REACHED();
default:
return EINVAL;
VERIFY_NOT_REACHED();
}
VERIFY_NOT_REACHED();
}
void SysFSPowerStateSwitchNode::reboot()