LibELF/LibELF/LoadableELF.cpp

@@ -27,6 +27,8 @@ namespace LibELF
 
 	LoadableELF::~LoadableELF()
 	{
+		if (!m_loaded)
+			return;
 		for (const auto& program_header : m_program_headers)
 		{
 			switch (program_header.p_type)
@@ -155,6 +157,29 @@ namespace LibELF
 		return false;
 	}
 
+	bool LoadableELF::is_address_space_free() const
+	{
+		for (const auto& program_header : m_program_headers)
+		{
+			switch (program_header.p_type)
+			{
+				case PT_NULL:
+					break;
+				case PT_LOAD:
+				{
+					vaddr_t page_vaddr = program_header.p_vaddr & PAGE_ADDR_MASK;
+					size_t pages = range_page_count(program_header.p_vaddr, program_header.p_memsz);
+					if (!m_page_table.is_range_free(page_vaddr, pages * PAGE_SIZE))
+						return false;
+					break;
+				}
+				default:
+					ASSERT_NOT_REACHED();
+			}
+		}
+		return true;
+	}
+
 	void LoadableELF::reserve_address_space()
 	{
 		for (const auto& program_header : m_program_headers)
@@ -174,6 +199,7 @@ namespace LibELF
 					ASSERT_NOT_REACHED();
 			}
 		}
+		m_loaded = true;
 	}
 
 	BAN::ErrorOr<void> LoadableELF::load_page_to_memory(vaddr_t address)

LibELF/include/LibELF/LoadableELF.h

@@ -27,6 +27,7 @@ namespace LibELF
 		Kernel::vaddr_t entry_point() const;
 
 		bool contains(Kernel::vaddr_t address) const;
+		bool is_address_space_free() const;
 		void reserve_address_space();
 
 		BAN::ErrorOr<void> load_page_to_memory(Kernel::vaddr_t address);
@@ -47,6 +48,7 @@ namespace LibELF
 		BAN::Vector<ElfNativeProgramHeader>	m_program_headers;
 		size_t m_virtual_page_count = 0;
 		size_t m_physical_page_count = 0;
+		bool m_loaded { false };
 	};
 
 }

kernel/kernel/Process.cpp

@@ -123,6 +123,11 @@ namespace Kernel
 		TRY(process->m_cmdline.back().append(path));
 
 		process->m_loadable_elf = TRY(load_elf_for_exec(credentials, path, "/"sv, process->page_table()));
+		if (!process->m_loadable_elf->is_address_space_free())
+		{
+			dprintln("Could not load ELF address space");
+			return BAN::Error::from_errno(ENOEXEC);
+		}
 		process->m_loadable_elf->reserve_address_space();
 
 		process->m_is_userspace = true;
@@ -460,6 +465,11 @@ namespace Kernel
 			m_loadable_elf.clear();
 
 			m_loadable_elf = TRY(load_elf_for_exec(m_credentials, executable_path, m_working_directory, page_table()));
+			if (!m_loadable_elf->is_address_space_free())
+			{
+				dprintln("ELF has unloadable address space");
+				MUST(sys_raise(SIGKILL));
+			}
 			m_loadable_elf->reserve_address_space();
 			m_userspace_info.entry = m_loadable_elf->entry_point();