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Kernel: Allow program headers to align on multiples of PAGE_SIZE

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These checks in `sys$execve` could trip up the system whenever you try
to execute an `.so` file. For example, double-clicking `libwasm.so` in
Terminal crashes the kernel.

This changes the program header alignment checks to reflect the same
checks in LibELF, and passes the requested alignment on to
`::try_allocate_range()`.
This commit is contained in:
Jelle Raaijmakers 2022-01-22 00:30:42 +01:00 • committed by Idan Horowitz
parent 67b7bbe1f6
commit df73e8b46b
1 changed files with 4 additions and 4 deletions
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8
Kernel/Syscalls/execve.cpp
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@ -306,7 +306,7 @@ static ErrorOr<LoadResult> load_elf_object(NonnullOwnPtr<Memory::AddressSpace> n
auto load_writable_section = [&](auto& program_header) -> ErrorOr<void> {
// Writable section: create a copy in memory.
VERIFY(program_header.alignment() == PAGE_SIZE);
VERIFY(program_header.alignment() % PAGE_SIZE == 0);
if (!elf_image.is_within_image(program_header.raw_data(), program_header.size_in_image())) {
dbgln("Shenanigans! Writable ELF PT_LOAD header sneaks outside of executable.");
@ -324,7 +324,7 @@ static ErrorOr<LoadResult> load_elf_object(NonnullOwnPtr<Memory::AddressSpace> n
size_t rounded_range_end = TRY(Memory::page_round_up(program_header.vaddr().offset(load_offset).offset(program_header.size_in_memory()).get()));
auto range_end = VirtualAddress { rounded_range_end };
auto range = TRY(new_space->try_allocate_range(range_base, range_end.get() - range_base.get()));
auto range = TRY(new_space->try_allocate_range(range_base, range_end.get() - range_base.get(), program_header.alignment()));
auto region = TRY(new_space->allocate_region(range, region_name->view(), prot, AllocationStrategy::Reserve));
// It's not always the case with PIE executables (and very well shouldn't be) that the
@ -348,7 +348,7 @@ static ErrorOr<LoadResult> load_elf_object(NonnullOwnPtr<Memory::AddressSpace> n
return load_writable_section(program_header);
// Non-writable section: map the executable itself in memory.
VERIFY(program_header.alignment() == PAGE_SIZE);
VERIFY(program_header.alignment() % PAGE_SIZE == 0);
int prot = 0;
if (program_header.is_readable())
prot |= PROT_READ;
@ -360,7 +360,7 @@ static ErrorOr<LoadResult> load_elf_object(NonnullOwnPtr<Memory::AddressSpace> n
auto range_base = VirtualAddress { Memory::page_round_down(program_header.vaddr().offset(load_offset).get()) };
size_t rounded_range_end = TRY(Memory::page_round_up(program_header.vaddr().offset(load_offset).offset(program_header.size_in_memory()).get()));
auto range_end = VirtualAddress { rounded_range_end };
auto range = TRY(new_space->try_allocate_range(range_base, range_end.get() - range_base.get()));
auto range = TRY(new_space->try_allocate_range(range_base, range_end.get() - range_base.get(), program_header.alignment()));
auto region = TRY(new_space->allocate_region_with_vmobject(range, *vmobject, program_header.offset(), elf_name->view(), prot, true));
if (should_allow_syscalls == ShouldAllowSyscalls::Yes)