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Kernel: Add basic Credentials for the system 

Now filesystem access/open, etc confirm that you have access for rwxs
This commit is contained in:
Bananymous 2023-06-11 19:52:13 +03:00
parent 46c34db6cb
commit c62e820bcf
13 changed files with 168 additions and 54 deletions
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10
LibELF/LibELF/ELF.cpp
View File

@ -21,12 +21,10 @@ namespace LibELF
{
#ifdef __is_kernel
BAN::ErrorOr<BAN::UniqPtr<ELF>> ELF::load_from_file(BAN::StringView file_path)
BAN::ErrorOr<BAN::UniqPtr<ELF>> ELF::load_from_file(BAN::RefPtr<Inode> inode)
{
auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(file_path, true));
PageTable::current().lock();
size_t page_count = BAN::Math::div_round_up<size_t>(file.inode->size(), PAGE_SIZE);
size_t page_count = BAN::Math::div_round_up<size_t>(inode->size(), PAGE_SIZE);
vaddr_t vaddr = PageTable::current().get_free_contiguous_pages(page_count, (vaddr_t)g_kernel_end);
auto virtual_range = BAN::UniqPtr<VirtualRange>::adopt(
VirtualRange::create(
@ -37,9 +35,9 @@ namespace LibELF
);
PageTable::current().unlock();
TRY(file.inode->read(0, (void*)vaddr, file.inode->size()));
TRY(inode->read(0, (void*)vaddr, inode->size()));
ELF* elf_ptr = new ELF(BAN::move(virtual_range), file.inode->size());
ELF* elf_ptr = new ELF(BAN::move(virtual_range), inode->size());
if (elf_ptr == nullptr)
return BAN::Error::from_errno(ENOMEM);

7
LibELF/include/LibELF/ELF.h
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@ -1,6 +1,7 @@
#pragma once
#ifdef __is_kernel
#include <kernel/FS/Inode.h>
#include <kernel/Memory/VirtualRange.h>
#endif
@ -16,8 +17,12 @@ namespace LibELF
class ELF
{
public:
#ifdef __is_kernel
static BAN::ErrorOr<BAN::UniqPtr<ELF>> load_from_file(BAN::RefPtr<Kernel::Inode>);
#else
static BAN::ErrorOr<BAN::UniqPtr<ELF>> load_from_file(BAN::StringView);
#endif
const Elf64FileHeader& file_header64() const;
const Elf64ProgramHeader& program_header64(size_t) const;
const Elf64SectionHeader& section_header64(size_t) const;

1
kernel/CMakeLists.txt
View File

@ -19,6 +19,7 @@ set(KERNEL_SOURCES
kernel/Errors.cpp
kernel/Font.cpp
kernel/FS/Ext2.cpp
kernel/FS/Inode.cpp
kernel/FS/VirtualFileSystem.cpp
kernel/Input/PS2Controller.cpp
kernel/Input/PS2Keyboard.cpp

40
kernel/include/kernel/Credentials.h Normal file
View File

@ -0,0 +1,40 @@
#pragma once
#include <sys/types.h>
namespace Kernel
{
class Credentials
{
public:
Credentials(uid_t ruid, uid_t euid, gid_t rgid, gid_t egid)
: m_ruid(ruid), m_euid(euid), m_suid(0)
, m_rgid(rgid), m_egid(egid), m_sgid(0)
{ }
uid_t ruid() const { return m_ruid; }
uid_t euid() const { return m_euid; }
uid_t suid() const { return m_suid; }
gid_t rgid() const { return m_rgid; }
gid_t egid() const { return m_egid; }
gid_t sgid() const { return m_sgid; }
private:
uid_t m_ruid, m_euid, m_suid;
gid_t m_rgid, m_egid, m_sgid;
};
}
namespace BAN::Formatter
{
template<typename F>
void print_argument(F putc, const Kernel::Credentials& credentials, const ValueFormat&)
{
print(putc, "(ruid {}, euid {})", credentials.ruid(), credentials.euid());
}
}

3
kernel/include/kernel/FS/Inode.h
View File

@ -6,6 +6,7 @@
#include <BAN/Vector.h>
#include <kernel/API/DirectoryEntry.h>
#include <kernel/Credentials.h>
#include <sys/types.h>
#include <time.h>
@ -56,6 +57,8 @@ namespace Kernel
public:
virtual ~Inode() {}
bool can_access(const Credentials&, int);
bool operator==(const Inode& other) const { return dev() == other.dev() && rdev() == other.rdev() && ino() == other.ino(); }
virtual ino_t ino() const = 0;

8
kernel/include/kernel/FS/VirtualFileSystem.h
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@ -11,21 +11,21 @@ namespace Kernel
class VirtualFileSystem : public FileSystem
{
public:
static BAN::ErrorOr<void> initialize(BAN::StringView);
static void initialize(BAN::StringView);
static VirtualFileSystem& get();
virtual ~VirtualFileSystem() {};
virtual BAN::RefPtr<Inode> root_inode() override { return m_root_fs->root_inode(); }
BAN::ErrorOr<void> mount(BAN::StringView, BAN::StringView);
BAN::ErrorOr<void> mount(FileSystem*, BAN::StringView);
BAN::ErrorOr<void> mount(const Credentials&, BAN::StringView, BAN::StringView);
BAN::ErrorOr<void> mount(const Credentials&, FileSystem*, BAN::StringView);
struct File
{
BAN::RefPtr<Inode> inode;
BAN::String canonical_path;
};
BAN::ErrorOr<File> file_from_absolute_path(BAN::StringView, bool follow_link);
BAN::ErrorOr<File> file_from_absolute_path(const Credentials&, BAN::StringView, int);
private:
VirtualFileSystem() = default;

11
kernel/include/kernel/Process.h
View File

@ -3,6 +3,7 @@
#include <BAN/String.h>
#include <BAN/StringView.h>
#include <BAN/Vector.h>
#include <kernel/Credentials.h>
#include <kernel/FS/Inode.h>
#include <kernel/Memory/FixedWidthAllocator.h>
#include <kernel/Memory/GeneralAllocator.h>
@ -37,7 +38,7 @@ namespace Kernel
public:
static Process* create_kernel(entry_t, void*);
static BAN::ErrorOr<Process*> create_userspace(BAN::StringView);
static BAN::ErrorOr<Process*> create_userspace(const Credentials&, BAN::StringView);
~Process();
[[noreturn]] void exit(int status);
@ -91,12 +92,12 @@ namespace Kernel
const userspace_info_t& userspace_info() const { return m_userspace_info; }
private:
Process(pid_t);
static Process* create_process();
Process(const Credentials&, pid_t);
static Process* create_process(const Credentials&);
static void register_process(Process*);
// Load an elf file to virtual address space of the current page table
static BAN::ErrorOr<BAN::UniqPtr<LibELF::ELF>> load_elf_for_exec(BAN::StringView file_path, const BAN::String& cwd, const BAN::Vector<BAN::StringView>& path_env);
static BAN::ErrorOr<BAN::UniqPtr<LibELF::ELF>> load_elf_for_exec(const Credentials&, BAN::StringView file_path, const BAN::String& cwd, const BAN::Vector<BAN::StringView>& path_env);
// Copy an elf file from the current page table to the processes own
void load_elf_to_memory(LibELF::ELF&);
@ -125,6 +126,8 @@ namespace Kernel
int waiting { 0 };
};
Credentials m_credentials;
BAN::Vector<OpenFileDescription> m_open_files;
BAN::Vector<VirtualRange*> m_mapped_ranges;

3
kernel/include/kernel/Terminal/TTY.h
View File

@ -108,7 +108,8 @@ namespace Kernel
TerminalDriver* m_terminal_driver { nullptr };
public:
virtual Mode mode() const override { return { Mode::IFCHR | Mode::IRUSR }; }
// FIXME: these should be crw------- with the owner being user
virtual Mode mode() const override { return { Mode::IFCHR | Mode::IRUSR | Mode::IWUSR | Mode::IRGRP | Mode::IWGRP | Mode::IROTH | Mode::IWOTH }; }
virtual uid_t uid() const override { return 0; }
virtual gid_t gid() const override { return 0; }
virtual dev_t rdev() const override { return m_rdev; }

59
kernel/kernel/FS/Inode.cpp Normal file
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@ -0,0 +1,59 @@
#include <kernel/FS/Inode.h>
#include <fcntl.h>
namespace Kernel
{
bool Inode::can_access(const Credentials& credentials, int flags)
{
if (credentials.euid() == 0)
return true;
// We treat O_SEARCH as O_RDONLY
if (flags & (O_RDONLY | O_SEARCH))
{
if (mode().mode & S_IROTH)
{ }
else if ((mode().mode & S_IRUSR) && credentials.euid() == uid())
{ }
else if ((mode().mode & S_IRGRP) && credentials.egid() == gid())
{ }
else
{
return false;
}
}
if (flags & O_WRONLY)
{
if (mode().mode & S_IWOTH)
{ }
else if ((mode().mode & S_IWUSR) && credentials.euid() == uid())
{ }
else if ((mode().mode & S_IWGRP) && credentials.egid() == gid())
{ }
else
{
return false;
}
}
if (flags & O_EXEC)
{
if (mode().mode & S_IXOTH)
{ }
else if ((mode().mode & S_IXUSR) && credentials.euid() == uid())
{ }
else if ((mode().mode & S_IXGRP) && credentials.egid() == gid())
{ }
else
{
return false;
}
}
return true;
}
}

37
kernel/kernel/FS/VirtualFileSystem.cpp
View File

@ -4,32 +4,27 @@
#include <kernel/FS/Ext2.h>
#include <kernel/FS/VirtualFileSystem.h>
#include <kernel/LockGuard.h>
#include <fcntl.h>
namespace Kernel
{
static VirtualFileSystem* s_instance = nullptr;
BAN::ErrorOr<void> VirtualFileSystem::initialize(BAN::StringView root)
void VirtualFileSystem::initialize(BAN::StringView root)
{
ASSERT(s_instance == nullptr);
s_instance = new VirtualFileSystem();
if (s_instance == nullptr)
return BAN::Error::from_errno(ENOMEM);
BAN::ScopeGuard guard([] { delete s_instance; s_instance = nullptr; } );
ASSERT(s_instance);
ASSERT(root.size() >= 5 && root.substring(0, 5) == "/dev/"sv);;
root = root.substring(5);
auto partition_inode = TRY(DeviceManager::get().read_directory_inode(root));
s_instance->m_root_fs = TRY(Ext2FS::create(*(Partition*)partition_inode.ptr()));
auto partition_inode = MUST(DeviceManager::get().read_directory_inode(root));
s_instance->m_root_fs = MUST(Ext2FS::create(*(Partition*)partition_inode.ptr()));
DeviceManager::get().set_blksize(s_instance->m_root_fs->root_inode()->blksize());
TRY(s_instance->mount(&DeviceManager::get(), "/dev"));
guard.disable();
return {};
MUST(s_instance->mount({ 0, 0, 0, 0 }, &DeviceManager::get(), "/dev"));
}
VirtualFileSystem& VirtualFileSystem::get()
@ -38,9 +33,9 @@ namespace Kernel
return *s_instance;
}
BAN::ErrorOr<void> VirtualFileSystem::mount(BAN::StringView partition, BAN::StringView target)
BAN::ErrorOr<void> VirtualFileSystem::mount(const Credentials& credentials, BAN::StringView partition, BAN::StringView target)
{
auto partition_file = TRY(file_from_absolute_path(partition, true));
auto partition_file = TRY(file_from_absolute_path(credentials, partition, true));
if (!partition_file.inode->is_device())
return BAN::Error::from_errno(ENOTBLK);
@ -49,12 +44,12 @@ namespace Kernel
return BAN::Error::from_errno(ENOTBLK);
auto* file_system = TRY(Ext2FS::create(*(Partition*)device));
return mount(file_system, target);
return mount(credentials, file_system, target);
}
BAN::ErrorOr<void> VirtualFileSystem::mount(FileSystem* file_system, BAN::StringView path)
BAN::ErrorOr<void> VirtualFileSystem::mount(const Credentials& credentials, FileSystem* file_system, BAN::StringView path)
{
auto file = TRY(file_from_absolute_path(path, true));
auto file = TRY(file_from_absolute_path(credentials, path, true));
if (!file.inode->mode().ifdir())
return BAN::Error::from_errno(ENOTDIR);
@ -82,7 +77,7 @@ namespace Kernel
return nullptr;
}
BAN::ErrorOr<VirtualFileSystem::File> VirtualFileSystem::file_from_absolute_path(BAN::StringView path, bool follow_link)
BAN::ErrorOr<VirtualFileSystem::File> VirtualFileSystem::file_from_absolute_path(const Credentials& credentials, BAN::StringView path, int flags)
{
LockGuard _(m_lock);
@ -129,6 +124,9 @@ namespace Kernel
}
else
{
if (!inode->can_access(credentials, O_RDONLY))
return BAN::Error::from_errno(EACCES);
inode = TRY(inode->read_directory_inode(path_part));
if (auto* mount_point = mount_from_host_inode(inode))
@ -140,7 +138,7 @@ namespace Kernel
path_parts.pop_back();
if (inode->mode().iflnk() && (follow_link || !path_parts.empty()))
if (inode->mode().iflnk() && (!(flags & O_NOFOLLOW) || !path_parts.empty()))
{
auto target = TRY(inode->link_target());
if (target.empty())
@ -174,6 +172,9 @@ namespace Kernel
}
}
if (!inode->can_access(credentials, flags))
return BAN::Error::from_errno(EACCES);
if (canonical_path.empty())
TRY(canonical_path.push_back('/'));

37
kernel/kernel/Process.cpp
View File

@ -18,10 +18,10 @@ namespace Kernel
static BAN::Vector<Process*> s_processes;
static SpinLock s_process_lock;
Process* Process::create_process()
Process* Process::create_process(const Credentials& credentials)
{
static pid_t s_next_pid = 1;
auto* process = new Process(s_next_pid++);
auto* process = new Process(credentials, s_next_pid++);
ASSERT(process);
return process;
}
@ -37,7 +37,7 @@ namespace Kernel
Process* Process::create_kernel(entry_t entry, void* data)
{
auto* process = create_process();
auto* process = create_process({ 0, 0, 0, 0 });
MUST(process->m_working_directory.push_back('/'));
auto* thread = MUST(Thread::create_kernel(entry, data, process));
process->add_thread(thread);
@ -45,11 +45,11 @@ namespace Kernel
return process;
}
BAN::ErrorOr<Process*> Process::create_userspace(BAN::StringView path)
BAN::ErrorOr<Process*> Process::create_userspace(const Credentials& credentials, BAN::StringView path)
{
auto elf = TRY(load_elf_for_exec(path, "/"sv, {}));
auto elf = TRY(load_elf_for_exec(credentials, path, "/"sv, {}));
auto* process = create_process();
auto* process = create_process(credentials);
MUST(process->m_working_directory.push_back('/'));
process->m_page_table = BAN::UniqPtr<PageTable>::adopt(MUST(PageTable::create_userspace()));;
@ -89,8 +89,9 @@ namespace Kernel
return process;
}
Process::Process(pid_t pid)
: m_pid(pid)
Process::Process(const Credentials& credentials, pid_t pid)
: m_credentials(credentials)
, m_pid(pid)
, m_tty(TTY::current())
{ }
@ -167,7 +168,7 @@ namespace Kernel
return {};
}
BAN::ErrorOr<BAN::UniqPtr<LibELF::ELF>> Process::load_elf_for_exec(BAN::StringView file_path, const BAN::String& cwd, const BAN::Vector<BAN::StringView>& path_env)
BAN::ErrorOr<BAN::UniqPtr<LibELF::ELF>> Process::load_elf_for_exec(const Credentials& credentials, BAN::StringView file_path, const BAN::String& cwd, const BAN::Vector<BAN::StringView>& path_env)
{
if (file_path.empty())
return BAN::Error::from_errno(ENOENT);
@ -204,7 +205,7 @@ namespace Kernel
TRY(absolute_path.push_back('/'));
TRY(absolute_path.append(file_path));
if (!VirtualFileSystem::get().file_from_absolute_path(absolute_path, true).is_error())
if (!VirtualFileSystem::get().file_from_absolute_path(credentials, absolute_path, O_EXEC).is_error())
break;
absolute_path.clear();
@ -214,7 +215,9 @@ namespace Kernel
return BAN::Error::from_errno(ENOENT);
}
auto elf_or_error = LibELF::ELF::load_from_file(absolute_path);
auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(credentials, absolute_path, O_EXEC));
auto elf_or_error = LibELF::ELF::load_from_file(file.inode);
if (elf_or_error.is_error())
{
if (elf_or_error.error().get_error_code() == EINVAL)
@ -240,7 +243,7 @@ namespace Kernel
BAN::ErrorOr<Process*> Process::fork(uintptr_t rsp, uintptr_t rip)
{
Process* forked = create_process();
Process* forked = create_process(m_credentials);
forked->m_page_table = BAN::UniqPtr<PageTable>::adopt(MUST(PageTable::create_userspace()));
@ -286,7 +289,7 @@ namespace Kernel
path_env = TRY(BAN::StringView(envp[i]).substring(5).split(':'));
}
auto elf = TRY(load_elf_for_exec(path, TRY(working_directory()), path_env));
auto elf = TRY(load_elf_for_exec(m_credentials, path, TRY(working_directory()), path_env));
LockGuard lock_guard(m_lock);
@ -456,7 +459,7 @@ namespace Kernel
BAN::String absolute_path = TRY(absolute_path_of(path));
auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(absolute_path, !(flags & O_NOFOLLOW)));
auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, absolute_path, flags));
LockGuard _(m_lock);
int fd = TRY(get_free_fd());
@ -592,7 +595,7 @@ namespace Kernel
auto directory = absolute_path.sv().substring(0, index);
auto file_name = absolute_path.sv().substring(index);
auto parent_file = TRY(VirtualFileSystem::get().file_from_absolute_path(directory, true));
auto parent_file = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, directory, O_WRONLY));
TRY(parent_file.inode->create_file(file_name, mode));
return {};
@ -606,7 +609,7 @@ namespace Kernel
absolute_source = TRY(absolute_path_of(source));
absolute_target = TRY(absolute_path_of(target));
}
TRY(VirtualFileSystem::get().mount(absolute_source, absolute_target));
TRY(VirtualFileSystem::get().mount(m_credentials, absolute_source, absolute_target));
return {};
}
@ -680,7 +683,7 @@ namespace Kernel
{
BAN::String absolute_path = TRY(absolute_path_of(path));
auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(absolute_path, true));
auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, absolute_path, O_SEARCH));
if (!file.inode->mode().ifdir())
return BAN::Error::from_errno(ENOTDIR);

4
kernel/kernel/kernel.cpp
View File

@ -173,14 +173,14 @@ static void init2(void* tty1)
DeviceManager::get().initialize_pci_devices();
DeviceManager::get().initialize_updater();
MUST(VirtualFileSystem::initialize(cmdline.root));
VirtualFileSystem::initialize(cmdline.root);
if (auto res = PS2Controller::initialize(); res.is_error())
dprintln("{}", res.error());
((TTY*)tty1)->initialize_device();
MUST(Process::create_userspace("/usr/bin/Shell"sv));
MUST(Process::create_userspace({ 0, 0, 0, 0 }, "/usr/bin/Shell"sv));
return;
Process::create_kernel(

2
userspace/ls/main.cpp
View File

@ -58,7 +58,7 @@ void list_directory(const char* path)
}
else
{
printf("%s %d %s", mode_string(st.st_mode), st.st_size, dirent->d_name);
printf("%s %6d %s", mode_string(st.st_mode), st.st_size, dirent->d_name);
}
}
else