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Kernel: Don't allocate memory for names of processes and threads

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Instead, use the FixedCharBuffer class to ensure we always use a static
buffer storage for these names. This ensures that if a Process or a
Thread were created, there's a guarantee that setting a new name will
never fail, as only copying of strings should be done to that static
storage.

The limits which are set are 32 characters for processes' names and 64
characters for thread names - this is because threads' names could be
more verbose than processes' names.
This commit is contained in:
Liav A 2023-07-17 18:34:19 +03:00 • committed by Andrew Kaster
parent 0d30f558f4
commit 3fd4997fc2
22 changed files with 102 additions and 110 deletions
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14
Kernel/Syscalls/prctl.cpp
View file

@ -55,14 +55,13 @@ ErrorOr<FlatPtr> Process::sys$prctl(int option, FlatPtr arg1, FlatPtr arg2)
int user_buffer_size = static_cast<int>(arg2);
if (user_buffer_size < 0)
return EINVAL;
if (user_buffer_size > 256)
return ENAMETOOLONG;
size_t buffer_size = static_cast<size_t>(user_buffer_size);
auto name = TRY(try_copy_kstring_from_user(buffer, buffer_size));
Process::Name process_name {};
TRY(try_copy_name_from_user_into_fixed_string_buffer<32>(buffer, process_name, buffer_size));
// NOTE: Reject empty and whitespace-only names, as they only confuse users.
if (name->view().is_whitespace())
if (process_name.representable_view().is_whitespace())
return EINVAL;
set_name(move(name));
set_name(process_name.representable_view());
return 0;
}
case PR_GET_PROCESS_NAME: {
@ -73,9 +72,10 @@ ErrorOr<FlatPtr> Process::sys$prctl(int option, FlatPtr arg1, FlatPtr arg2)
return EINVAL;
size_t buffer_size = static_cast<size_t>(arg2);
TRY(m_name.with([&buffer, buffer_size](auto& name) -> ErrorOr<void> {
if (name->length() + 1 > buffer_size)
auto view = name.representable_view();
if (view.length() + 1 > buffer_size)
return ENAMETOOLONG;
return copy_to_user(buffer, name->characters(), name->length() + 1);
return copy_to_user(buffer, view.characters_without_null_termination(), view.length() + 1);
}));
return 0;
}