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Kernel+Userland: Convert process syscall region enforce flag to SetOnce

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This flag is set only once, and should never reset once it has been set,
making it an ideal SetOnce use-case.
It also simplifies the expected conditions for the enabling prctl call,
as we don't expect a boolean flag, but rather the specific prctl option
will always set (enable) Process' AddressSpace syscall region enforcing.
This commit is contained in:
Liav A. 2024-05-03 13:45:37 +03:00 committed by Andrew Kaster
parent 2cb86c1309
commit e756567341
4 changed files with 9 additions and 11 deletions
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7
Kernel/Memory/AddressSpace.h
View File

@ -8,6 +8,7 @@
#pragma once
#include <AK/RedBlackTree.h>
#include <AK/SetOnce.h>
#include <AK/Vector.h>
#include <Kernel/Arch/PageDirectory.h>
#include <Kernel/Library/LockWeakPtr.h>
@ -48,8 +49,8 @@ public:
ErrorOr<Vector<Region*, 4>> find_regions_intersecting(VirtualRange const&);
bool enforces_syscall_regions() const { return m_enforces_syscall_regions; }
void set_enforces_syscall_regions(bool b) { m_enforces_syscall_regions = b; }
bool enforces_syscall_regions() const { return m_enforces_syscall_regions.was_set(); }
void set_enforces_syscall_regions() { m_enforces_syscall_regions.set(); }
void remove_all_regions(Badge<Process>);
@ -68,7 +69,7 @@ private:
RegionTree m_region_tree;
bool m_enforces_syscall_regions { false };
SetOnce m_enforces_syscall_regions;
};
}

3
Kernel/Syscalls/fork.cpp
View File

@ -164,7 +164,8 @@ ErrorOr<FlatPtr> Process::sys$fork(RegisterState& regs)
TRY(address_space().with([&](auto& parent_space) {
return child->address_space().with([&](auto& child_space) -> ErrorOr<void> {
child_space->set_enforces_syscall_regions(parent_space->enforces_syscall_regions());
if (parent_space->enforces_syscall_regions())
child_space->set_enforces_syscall_regions();
for (auto& region : parent_space->region_tree().regions()) {
dbgln_if(FORK_DEBUG, "fork: cloning Region '{}' @ {}", region.name(), region.vaddr());
auto region_clone = TRY(region.try_clone());

8
Kernel/Syscalls/prctl.cpp
View File

@ -26,14 +26,10 @@ ErrorOr<FlatPtr> Process::sys$prctl(int option, FlatPtr arg1, FlatPtr arg2, Flat
return space->enforces_syscall_regions();
});
case PR_SET_NO_NEW_SYSCALL_REGION_ANNOTATIONS: {
if (arg1 != 0 && arg1 != 1)
if (arg1 != 0)
return EINVAL;
bool prohibit_new_annotated_syscall_regions = (arg1 == 1);
return address_space().with([&](auto& space) -> ErrorOr<FlatPtr> {
if (space->enforces_syscall_regions() && !prohibit_new_annotated_syscall_regions)
return EPERM;
space->set_enforces_syscall_regions(prohibit_new_annotated_syscall_regions);
space->set_enforces_syscall_regions();
return 0;
});
return 0;

2
Userland/Libraries/LibELF/DynamicLinker.cpp
View File

@ -739,7 +739,7 @@ Examples of static-pie ELF objects are ELF packers, and the system dynamic loade
entry_point = entry_point.offset(main_executable_loader->base_address().get());
auto entry_point_function = reinterpret_cast<EntryPointFunction>(entry_point.as_ptr());
int rc = syscall(SC_prctl, PR_SET_NO_NEW_SYSCALL_REGION_ANNOTATIONS, 1, 0, nullptr);
int rc = syscall(SC_prctl, PR_SET_NO_NEW_SYSCALL_REGION_ANNOTATIONS, 0, 0, nullptr);
if (rc < 0) {
VERIFY_NOT_REACHED();
}