Kernel/LibC/Userspace: Implement chown and set tty owner on login

kernel/include/kernel/FS/Inode.h

@@ -101,6 +101,7 @@ namespace Kernel
 		BAN::ErrorOr<size_t> write(off_t, BAN::ConstByteSpan buffer);
 		BAN::ErrorOr<void> truncate(size_t);
 		BAN::ErrorOr<void> chmod(mode_t);
+		BAN::ErrorOr<void> chown(uid_t, gid_t);
 		bool has_data() const;
 
 	protected:
@@ -119,6 +120,7 @@ namespace Kernel
 		virtual BAN::ErrorOr<size_t> write_impl(off_t, BAN::ConstByteSpan)	{ return BAN::Error::from_errno(ENOTSUP); }
 		virtual BAN::ErrorOr<void> truncate_impl(size_t)					{ return BAN::Error::from_errno(ENOTSUP); }
 		virtual BAN::ErrorOr<void> chmod_impl(mode_t)						{ return BAN::Error::from_errno(ENOTSUP); }
+		virtual BAN::ErrorOr<void> chown_impl(uid_t, gid_t)					{ return BAN::Error::from_errno(ENOTSUP); }
 		virtual bool has_data_impl() const { dwarnln("nonblock not supported"); return true; }
 
 	protected:

kernel/include/kernel/Process.h

@@ -108,6 +108,7 @@ namespace Kernel
 		BAN::ErrorOr<long> sys_pread(int fd, void* buffer, size_t count, off_t offset);
 
 		BAN::ErrorOr<long> sys_chmod(const char*, mode_t);
+		BAN::ErrorOr<long> sys_chown(const char*, uid_t, gid_t);
 
 		BAN::ErrorOr<long> sys_pipe(int fildes[2]);
 		BAN::ErrorOr<long> sys_dup(int fildes);

kernel/include/kernel/Terminal/TTY.h

@@ -41,6 +41,9 @@ namespace Kernel
 
 		virtual void clear() = 0;
 
+		virtual BAN::ErrorOr<void> chmod_impl(mode_t) override;
+		virtual BAN::ErrorOr<void> chown_impl(uid_t, gid_t) override;
+
 		virtual bool has_data_impl() const override;
 
 	protected:

kernel/kernel/FS/Inode.cpp

@@ -141,6 +141,12 @@ namespace Kernel
 		return chmod_impl(mode);
 	}
 
+	BAN::ErrorOr<void> Inode::chown(uid_t uid, gid_t gid)
+	{
+		LockGuard _(m_lock);
+		return chown_impl(uid, gid);
+	}
+
 	bool Inode::has_data() const
 	{
 		LockGuard _(m_lock);

kernel/kernel/Process.cpp

@@ -886,6 +886,18 @@ namespace Kernel
 		return 0;
 	}
 
+	BAN::ErrorOr<long> Process::sys_chown(const char* path, uid_t uid, gid_t gid)
+	{
+		LockGuard _(m_lock);
+		validate_string_access(path);
+
+		auto absolute_path = TRY(absolute_path_of(path));
+		auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, absolute_path, O_WRONLY));
+		TRY(file.inode->chown(uid, gid));
+
+		return 0;
+	}
+
 	BAN::ErrorOr<long> Process::sys_pipe(int fildes[2])
 	{
 		LockGuard _(m_lock);

kernel/kernel/Syscall.cpp

@@ -211,6 +211,9 @@ namespace Kernel
 		case SYS_PREAD:
 			ret = Process::current().sys_pread((int)arg1, (void*)arg2, (size_t)arg3, (off_t)arg4);
 			break;
+		case SYS_CHOWN:
+			ret = Process::current().sys_chown((const char*)arg1, (uid_t)arg2, (gid_t)arg3);
+			break;
 		default:
 			dwarnln("Unknown syscall {}", syscall);
 			break;

kernel/kernel/Terminal/Serial.cpp

@@ -179,7 +179,7 @@ namespace Kernel
 	}
 
 	SerialTTY::SerialTTY(Serial serial)
-		: TTY(0660, 0, 0)
+		: TTY(0600, 0, 0)
 		, m_serial(serial)
 		, m_rdev(next_rdev())
 	{

kernel/kernel/Terminal/TTY.cpp

@@ -105,6 +105,21 @@ namespace Kernel
 		initialized = true;
 	}
 
+	BAN::ErrorOr<void> TTY::chmod_impl(mode_t mode)
+	{
+		ASSERT((mode & Inode::Mode::TYPE_MASK) == 0);
+		m_inode_info.mode &= Inode::Mode::TYPE_MASK;
+		m_inode_info.mode |= mode;
+		return {};
+	}
+
+	BAN::ErrorOr<void> TTY::chown_impl(uid_t uid, gid_t gid)
+	{
+		m_inode_info.uid = uid;
+		m_inode_info.gid = gid;
+		return {};
+	}
+
 	void TTY::on_key_event(Input::KeyEvent event)
 	{
 		LockGuard _(m_lock);

kernel/kernel/Terminal/VirtualTTY.cpp

@@ -42,7 +42,7 @@ namespace Kernel
 	}
 
 	VirtualTTY::VirtualTTY(TerminalDriver* driver)
-		: TTY(0666, 0, 0)
+		: TTY(0600, 0, 0)
 		, m_terminal_driver(driver)
 		, m_rdev(next_rdev())
 	{

libc/include/sys/syscall.h

@@ -61,6 +61,7 @@ __BEGIN_DECLS
 #define SYS_READLINKAT 60
 #define SYS_MSYNC 61
 #define SYS_PREAD 62
+#define SYS_CHOWN 63
 
 __END_DECLS
 

libc/unistd.cpp

@@ -270,6 +270,11 @@ int chdir(const char* path)
 	return syscall(SYS_SET_PWD, path);
 }
 
+int chown(const char* path, uid_t owner, gid_t group)
+{
+	return syscall(SYS_CHOWN, path, owner, group);
+}
+
 void sync(void)
 {
 	syscall(SYS_SYNC, false);

userspace/init/main.cpp

@@ -63,6 +63,18 @@ int main()
 		if (pwd == nullptr)
 			continue;
 
+		if (chown("/dev/tty", pwd->pw_uid, pwd->pw_gid) == -1)
+		{
+			perror("chown");
+			continue;
+		}
+
+		if (chmod("/dev/tty", 0600) == -1)
+		{
+			perror("chmod");
+			continue;
+		}
+
 		pid_t pid = fork();
 		if (pid == 0)
 		{