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Kernel: Use KString all the way in sys$execve()

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This patch converts all the usage of AK::String around sys$execve() to
using KString instead, allowing us to catch and propagate OOM errors.

It also required changing the kernel CommandLine helper class to return
a vector of KString for the userspace init program arguments.
This commit is contained in:
Andreas Kling 2021-09-09 11:36:40 +02:00
parent 92363a4ef8
commit dd82f68326
6 changed files with 48 additions and 41 deletions
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48
Kernel/Syscalls/execve.cpp
View file

@ -42,7 +42,7 @@ struct LoadResult {
static Vector<ELF::AuxiliaryValue> generate_auxiliary_vector(FlatPtr load_base, FlatPtr entry_eip, UserID uid, UserID euid, GroupID gid, GroupID egid, StringView executable_path, Optional<Process::ScopedDescriptionAllocation> const& main_program_fd_allocation);
static bool validate_stack_size(const Vector<String>& arguments, const Vector<String>& environment)
static bool validate_stack_size(NonnullOwnPtrVector<KString> const& arguments, NonnullOwnPtrVector<KString>& environment)
{
size_t total_arguments_size = 0;
size_t total_environment_size = 0;
@ -68,8 +68,8 @@ static bool validate_stack_size(const Vector<String>& arguments, const Vector<St
return true;
}
static KResultOr<FlatPtr> make_userspace_context_for_main_thread([[maybe_unused]] ThreadRegisters& regs, Memory::Region& region, Vector<String> arguments,
Vector<String> environment, Vector<ELF::AuxiliaryValue> auxiliary_values)
static KResultOr<FlatPtr> make_userspace_context_for_main_thread([[maybe_unused]] ThreadRegisters& regs, Memory::Region& region, NonnullOwnPtrVector<KString> const& arguments,
NonnullOwnPtrVector<KString> const& environment, Vector<ELF::AuxiliaryValue> auxiliary_values)
{
FlatPtr new_sp = region.range().end().get();
@ -99,14 +99,14 @@ static KResultOr<FlatPtr> make_userspace_context_for_main_thread([[maybe_unused]
Vector<FlatPtr> argv_entries;
for (auto& argument : arguments) {
push_string_on_new_stack(argument);
push_string_on_new_stack(argument.view());
if (!argv_entries.try_append(new_sp))
return ENOMEM;
}
Vector<FlatPtr> env_entries;
for (auto& variable : environment) {
push_string_on_new_stack(variable);
push_string_on_new_stack(variable.view());
if (!env_entries.try_append(new_sp))
return ENOMEM;
}
@ -433,7 +433,7 @@ Process::load(NonnullRefPtr<OpenFileDescription> main_program_description,
return interpreter_load_result;
}
KResult Process::do_exec(NonnullRefPtr<OpenFileDescription> main_program_description, Vector<String> arguments, Vector<String> environment,
KResult Process::do_exec(NonnullRefPtr<OpenFileDescription> main_program_description, NonnullOwnPtrVector<KString> arguments, NonnullOwnPtrVector<KString> environment,
RefPtr<OpenFileDescription> interpreter_description, Thread*& new_main_thread, u32& prev_flags, const ElfW(Ehdr) & main_program_header)
{
VERIFY(is_user_process());
@ -514,8 +514,8 @@ KResult Process::do_exec(NonnullRefPtr<OpenFileDescription> main_program_descrip
Memory::MemoryManager::enter_address_space(*m_space);
m_executable = main_program_description->custody();
m_arguments = arguments;
m_environment = environment;
m_arguments = move(arguments);
m_environment = move(environment);
m_veil_state = VeilState::None;
m_unveiled_paths.clear();
@ -554,7 +554,7 @@ KResult Process::do_exec(NonnullRefPtr<OpenFileDescription> main_program_descrip
// NOTE: We create the new stack before disabling interrupts since it will zero-fault
// and we don't want to deal with faults after this point.
auto make_stack_result = make_userspace_context_for_main_thread(new_main_thread->regs(), *load_result.stack_region.unsafe_ptr(), move(arguments), move(environment), move(auxv));
auto make_stack_result = make_userspace_context_for_main_thread(new_main_thread->regs(), *load_result.stack_region.unsafe_ptr(), m_arguments, m_environment, move(auxv));
if (make_stack_result.is_error())
return make_stack_result.error();
FlatPtr new_userspace_sp = make_stack_result.value();
@ -672,12 +672,12 @@ static Vector<ELF::AuxiliaryValue> generate_auxiliary_vector(FlatPtr load_base,
return auxv;
}
static KResultOr<Vector<String>> find_shebang_interpreter_for_executable(char const first_page[], size_t nread)
static KResultOr<NonnullOwnPtrVector<KString>> find_shebang_interpreter_for_executable(char const first_page[], size_t nread)
{
int word_start = 2;
int word_length = 0;
size_t word_length = 0;
if (nread > 2 && first_page[0] == '#' && first_page[1] == '!') {
Vector<String> interpreter_words;
NonnullOwnPtrVector<KString> interpreter_words;
for (size_t i = 2; i < nread; ++i) {
if (first_page[i] == '\n') {
@ -690,15 +690,18 @@ static KResultOr<Vector<String>> find_shebang_interpreter_for_executable(char co
if (first_page[i] == ' ') {
if (word_length > 0) {
interpreter_words.append(String(&first_page[word_start], word_length));
auto word = TRY(KString::try_create(StringView { &first_page[word_start], word_length }));
interpreter_words.append(move(word));
}
word_length = 0;
word_start = i + 1;
}
}
if (word_length > 0)
interpreter_words.append(String(&first_page[word_start], word_length));
if (word_length > 0) {
auto word = TRY(KString::try_create(StringView { &first_page[word_start], word_length }));
interpreter_words.append(move(word));
}
if (!interpreter_words.is_empty())
return interpreter_words;
@ -772,7 +775,7 @@ KResultOr<RefPtr<OpenFileDescription>> Process::find_elf_interpreter_for_executa
return nullptr;
}
KResult Process::exec(NonnullOwnPtr<KString> path, Vector<String> arguments, Vector<String> environment, int recursion_depth)
KResult Process::exec(NonnullOwnPtr<KString> path, NonnullOwnPtrVector<KString> arguments, NonnullOwnPtrVector<KString> environment, int recursion_depth)
{
if (recursion_depth > 2) {
dbgln("exec({}): SHENANIGANS! recursed too far trying to find #! interpreter", path);
@ -807,9 +810,8 @@ KResult Process::exec(NonnullOwnPtr<KString> path, Vector<String> arguments, Vec
auto shebang_result = find_shebang_interpreter_for_executable(first_page, nread);
if (!shebang_result.is_error()) {
auto shebang_words = shebang_result.release_value();
auto shebang_path = TRY(KString::try_create(shebang_words.first()));
// FIXME: Don't use String.
arguments[0] = path->view();
auto shebang_path = TRY(shebang_words.first().try_clone());
arguments.ptr_at(0) = move(path);
if (!arguments.try_prepend(move(shebang_words)))
return ENOMEM;
return exec(move(shebang_path), move(arguments), move(environment), ++recursion_depth);
@ -886,18 +888,16 @@ KResultOr<FlatPtr> Process::sys$execve(Userspace<const Syscall::SC_execve_params
TRY(copy_from_user(strings.data(), list.strings, size.value()));
for (size_t i = 0; i < list.length; ++i) {
auto string = TRY(try_copy_kstring_from_user(strings[i]));
// FIXME: Don't convert to String here, use KString all the way.
auto ak_string = String(string->view());
if (!output.try_append(move(ak_string)))
if (!output.try_append(move(string)))
return ENOMEM;
}
return KSuccess;
};
Vector<String> arguments;
NonnullOwnPtrVector<KString> arguments;
TRY(copy_user_strings(params.arguments, arguments));
Vector<String> environment;
NonnullOwnPtrVector<KString> environment;
TRY(copy_user_strings(params.environment, environment));
auto result = exec(move(path), move(arguments), move(environment));