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Kernel: Use an ArmedScopeGuard to revert changes after failed mmap

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Hendiadyoin1 2022-02-16 23:33:18 +01:00 • committed by Brian Gianforcaro
parent a4e3ae0ee9
commit 790d620b39
1 changed files with 12 additions and 1 deletions
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13
Kernel/Syscalls/mmap.cpp
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@ -5,6 +5,7 @@
* SPDX-License-Identifier: BSD-2-Clause * SPDX-License-Identifier: BSD-2-Clause
*/ */
#include <AK/kmalloc.h>
#include <Kernel/Arch/SmapDisabler.h> #include <Kernel/Arch/SmapDisabler.h>
#include <Kernel/Arch/x86/MSR.h> #include <Kernel/Arch/x86/MSR.h>
#include <Kernel/Arch/x86/SafeMem.h> #include <Kernel/Arch/x86/SafeMem.h>
@ -184,8 +185,16 @@ ErrorOr<FlatPtr> Process::sys$mmap(Userspace<const Syscall::SC_mmap_params*> use
return EINVAL; return EINVAL;
Memory::Region* region = nullptr; Memory::Region* region = nullptr;
Memory::VirtualRange range { {}, 0 };
auto range = TRY([&]() -> ErrorOr<Memory::VirtualRange> { ArmedScopeGuard scope_guard = [&] {
if (region)
address_space().deallocate_region(*region);
else if (range.is_valid())
address_space().page_directory().range_allocator().deallocate(range);
};
range = TRY([&]() -> ErrorOr<Memory::VirtualRange> {
if (map_randomized) if (map_randomized)
return address_space().page_directory().range_allocator().try_allocate_randomized(rounded_size, alignment); return address_space().page_directory().range_allocator().try_allocate_randomized(rounded_size, alignment);
@ -248,6 +257,8 @@ ErrorOr<FlatPtr> Process::sys$mmap(Userspace<const Syscall::SC_mmap_params*> use
PerformanceManager::add_mmap_perf_event(*this, *region); PerformanceManager::add_mmap_perf_event(*this, *region);
scope_guard.disarm();
return region->vaddr().get(); return region->vaddr().get();
} }