Update kraft for EPT.

Change the build process for EPT such that IDs are used in cross-compartment calls instead of function pointers. This is necessary to restrict control flow of cross-compartment calls to actual function boundaries instead of arbitrary pointers. Also make the maximum number of threads supported by the EPT backend configurable. Signed-off-by: Sebastian Rauch <[email protected]>
project-flexos · Dec 14, 2021 · 7bbfdc8 · 7bbfdc8
1 parent 064f674
commit 7bbfdc8
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Showing 5 changed files with 195 additions and 7 deletions.
diff --git a/kraft/app/app.py b/kraft/app/app.py
@@ -91,6 +91,15 @@
 
 
 class Application(Component):
+    # path of file where the names of functions called via gate are collected
+    VMEPT_FUNC_LIST_PATH = "/tmp/flexos_vmept_rpc_id_data"
+
+    # name and path of auto-generated header file containing the function addresses
+    VMEPT_ADDR_TABLE_NAME = "vmept_addr_table"
+
+    # where to put auto-generated header files (relative to the unikraft build directory)
+    VMEPT_AUTOGEN_INCLUDE_PATH = "lib/flexos-core/include/flexos/impl"
+
     _type = ComponentType.APP
 
     _config = None
@@ -605,6 +614,29 @@ def fetch(ctx, self, verbose=False):
 
         return self.make(extra, verbose)
 
+    # generate a header containing an array with the addresses of functions called via EPT-gate
+    def vmept_gen_address_table_header(self, func_names, header_name, addr_map = {}, write_to_file = True):
+        include_guard = "%s_H" % header_name.upper()
+        header_code = "#ifndef %s\n" % include_guard
+        header_code += "#define %s\n\n" % include_guard
+        header_code += 'static const void* flexos_vmept_addr_table[] __attribute__((section (".rodata"))) = {\n'
+        num_entries = len(func_names)
+        i = 0
+        for fname in func_names:
+            i += 1
+            sep = "," if i < num_entries else " "
+            addr = addr_map[fname] if fname in addr_map else 0
+            header_code += "\t(void*) 0x%016x%s /* %s */\n" % (addr, sep, fname)
+        header_code += "};\n\n"
+        header_code += "#endif /* %s */" % include_guard
+        if write_to_file:
+            addr_table_path = os.path.join(self.unikraft.localdir, self.VMEPT_AUTOGEN_INCLUDE_PATH)
+            addr_table_path = os.path.join(addr_table_path, self.VMEPT_ADDR_TABLE_NAME + ".h")
+            addr_table_file = open(addr_table_path, "w")
+            addr_table_file.write(header_code)
+            addr_table_file.close()
+        return header_code
+
     @click.pass_context
     def compartmentalize(ctx, self):
         self.find_files()
@@ -792,6 +824,12 @@ def simple_replace(template_path, path, marker, shstack_enabled=True):
         cmd = ["diff", "-urNp", backup_src, filep]
         subprocess.call(cmd, stdout=fulldiff, stderr=subprocess.STDOUT)
 
+        is_ept = type(self.compartments[0].mechanism.driver) == VMEPTDriver
+        if is_ept and not os.path.isfile(self.VMEPT_FUNC_LIST_PATH):
+                # make sure this file exists
+                rpc_id_file = open(self.VMEPT_FUNC_LIST_PATH, "w")
+                rpc_id_file.close()
+
         # now do library-specific rewrites
         for lib in self.libraries:
             # first add per-library linker scripts
@@ -810,6 +848,13 @@ def simple_replace(template_path, path, marker, shstack_enabled=True):
                 str(lib.compartment.number))
             gr_rule = ""
 
+            ept_rpc_id_prefix = "_RPC_ID_" if is_ept else ""
+            if (is_ept):
+                rpc_id_gen_template = get_sec_rule("rpc_id_gen.cocci.in")
+                rpc_id_gen_template = rpc_id_gen_template.replace("{{ filename }}",
+                    "'" + self.VMEPT_FUNC_LIST_PATH + "'")
+                gr_rule = rpc_id_gen_template + "\n"
+
             def gr_gen_rule(dest_name, dest_comp):
                 gr_rule = str(gr_rule_template)
                 name = dest_name
@@ -825,6 +870,9 @@ def gr_gen_rule(dest_name, dest_comp):
                 if dest_comp == lib.compartment:
                     # FIXME magic value, put somewhere
                     gr_gate = "flexos_nop_gate"
+                    gr_rule = gr_rule.replace("{{ ept_id_prefix }}", "")
+                else:
+                    gr_rule = gr_rule.replace("{{ ept_id_prefix }}", ept_rpc_id_prefix)
 
                 gr_rule = gr_rule.replace("{{ gate }}", gr_gate)
                 gr_rule = gr_rule.replace("{{ gate_r }}", gr_gate + "_r")
@@ -868,6 +916,7 @@ def cb_gen_rule(dest_name, dest_comp):
             # with future upstream releases of Coccinelle, talking about it with Julia
             whitelisted_libs = ["libvfscore", "libuknetdev", "newlib",
                                 "libuksched", "libuksignal", "libukboot"]
+
             for dest_lib in self.libraries:
                 if (not dest_lib.compartment.default) and (dest_lib.name != lib.name):
                     # this library is not in the default compartment, add a specific rule
@@ -920,6 +969,34 @@ def cb_gen_rule(dest_name, dest_comp):
 
             coccinelle_rewrite(lib, rule_file, fulldiff)
 
+        # generate a header with macros defining IDs for all
+        # functions given by function_names
+        def vmept_gen_rpc_id_macro_header(function_names, header_name):
+            include_guard = "%s_H" % header_name.upper()
+            header_code = "#ifndef %s\n" % include_guard
+            header_code += "#define %s\n\n" % include_guard
+            rpc_id = 0
+            for fname in function_names:
+                header_code += "#define %s%s %d\n" % (ept_rpc_id_prefix, fname, rpc_id)
+                rpc_id += 1
+            header_code += "\n#define FLEXOS_VMEPT_RPCID_CNT %d\n\n" % rpc_id
+            header_code += "#endif /* %s */" % include_guard
+            return header_code
+
+        if (is_ept):
+            rpc_id_file = open(self.VMEPT_FUNC_LIST_PATH, "r")
+            fnames = list(map(str.strip, rpc_id_file.readlines()))
+            rpc_id_file.close()
+            id_header_name = "vmept_rpc_id"
+            addr_table_name = "flexos_%s" % self.VMEPT_ADDR_TABLE_NAME
+            id_header_code = vmept_gen_rpc_id_macro_header(fnames, id_header_name)
+            addr_table_code = self.vmept_gen_address_table_header(fnames, addr_table_name, write_to_file = True)
+            id_header_path = os.path.join(self.unikraft.localdir, self.VMEPT_AUTOGEN_INCLUDE_PATH)
+            id_header_path = os.path.join(id_header_path, id_header_name + ".h")
+            id_header_file = open(id_header_path, "w")
+            id_header_file.write(id_header_code)
+            id_header_file.close()
+
         logger.info("Full diff of rewritings: %s" % fulldifff)
         fulldiff.close()
 

diff --git a/kraft/cmd/build.py b/kraft/cmd/build.py
@@ -84,6 +84,25 @@ def simple_replace(template_path, marker):
         if lib.name.startswith("app"):
             appcomp = lib.compartment
 
+    # get VMEPT config options
+    max_threads_shift = 8 # max hreads is (1 << max_threads_shift)
+    with open(os.path.join(app.localdir, ".config")) as conf:
+        conf_data = conf.read()
+        if 'CONFIG_LIBFLEXOS_VMEPT_MAX_THREADS_256=y' in conf_data:
+            max_threads_shift = 8
+        if 'CONFIG_LIBFLEXOS_VMEPT_MAX_THREADS_128=y' in conf_data:
+            max_threads_shift = 7
+        if 'CONFIG_LIBFLEXOS_VMEPT_MAX_THREADS_64=y' in conf_data:
+            max_threads_shift = 6
+        if 'CONFIG_LIBFLEXOS_VMEPT_MAX_THREADS_32=y' in conf_data:
+            max_threads_shift = 5
+        if 'CONFIG_LIBFLEXOS_VMEPT_MAX_THREADS_16=y' in conf_data:
+            max_threads_shift = 4
+        if 'CONFIG_LIBFLEXOS_VMEPT_MAX_THREADS_8=y' in conf_data:
+            max_threads_shift = 3
+        if 'CONFIG_LIBFLEXOS_VMEPT_MAX_THREADS_4=y' in conf_data:
+            max_threads_shift = 2
+
     i = 0
     logger.info("Building with VM/EPT: " + str(no_ept) + " images to build.")
     for comp in app.compartments:
@@ -92,7 +111,8 @@ def simple_replace(template_path, marker):
         # edit build args
         extra_args = ["CFLAGS_EXTRA=-DFLEXOS_VMEPT_COMP_ID=" + str(i) 
                     + " -DFLEXOS_VMEPT_COMP_COUNT=" + str(no_ept)
-                    + " -DFLEXOS_VMEPT_APPCOMP=" + str(appcomp.number)]
+                    + " -DFLEXOS_VMEPT_APPCOMP=" + str(appcomp.number)
+                    + " -DFLEXOS_VMEPT_MAX_THREADS_SHIFT=" + str(max_threads_shift)]
         if fast:
             extra_args.insert(0, "-j")
 
@@ -111,6 +131,43 @@ def simple_replace(template_path, marker):
                          "of the make command (code " + str(return_code) + ")")
             return
 
+        for target in app.binaries:
+            # insert correct addresses
+            funcname_file = open(Application.VMEPT_FUNC_LIST_PATH, "r")
+            fnames = list(map(str.strip, funcname_file.readlines()))
+            funcname_file.close()
+
+            addr_map = {}
+            for fname in fnames:
+                addr_map[fname] = 0
+
+            readelf = subprocess.Popen(['readelf', '-sW', target.binary_debug], stdout = subprocess.PIPE)
+            output = subprocess.check_output(['awk', '{if ($4 == "FUNC") { print $2,$8 } }'], stdin = readelf.stdout).decode()
+            readelf.wait()
+
+            raw_lines = output.splitlines()
+
+            entries = []
+            for line in raw_lines:
+                fields = line.split()
+                address = int(fields[0], 16)
+                name = fields[1]
+                if name in addr_map:
+                    addr_map[name] = address
+
+            patched_code = app.vmept_gen_address_table_header(fnames,
+                Application.VMEPT_ADDR_TABLE_NAME, addr_map, write_to_file = True)
+
+        # build again
+        return_code = make_progressbar(app.make_raw(verbose=verbose,
+            extra=extra_args))
+
+        if (return_code > 0):
+            # there was probably an error
+            logger.error("Aborting build due to probable error during execution "
+                         "of the make command (code " + str(return_code) + ")")
+            return
+
         # secure image (so that it doesn't get overwritten)
         for target in app.binaries:
             os.rename(target.binary, target.binary + ".comp" + str(i))

diff --git a/kraft/sec/__init__.py b/kraft/sec/__init__.py
@@ -150,7 +150,9 @@ def coccinelle_rewrite(lib, rule_file, fulldiff):
 
         with open(log, 'wb') as logf:
             try:
-                cmd1 = ["spatch", "-j", "6", "-in_place", "-sp_file", rule_file, file]
+                # we can't use parallel jobs when building for EPT since this leads to
+                # @finalize scripts being called too early
+                cmd1 = ["spatch", "-in_place", "-sp_file", rule_file, file]
                 cmd2 = ["diff", "-urNp", backup_src, file]
                 logf.write(bytes("$ " + " ".join(cmd1) + "\n", 'utf-8'))
                 logf.flush()

diff --git a/kraft/sec/replacements/ukboot_init_sections.in b/kraft/sec/replacements/ukboot_init_sections.in
@@ -2,4 +2,4 @@
 					 (void *) __uk_image_symbol(_ecomp{{ comp_nr }}));
 	PROTECT_SECTION("bss_comp{{ comp_nr }}", {{ comp_nr }}, (void *) __uk_image_symbol(_bss_comp{{ comp_nr }}),
 					(void *) __uk_image_symbol(_ebss_comp{{ comp_nr }}));
-	ASSIGN_HEAP("comp{{ comp_nr }}", {{ comp_nr }} /* key */, 1000 /* size */, flexos_comp{{ comp_nr }}_alloc);
+	ASSIGN_HEAP("comp{{ comp_nr }}", {{ comp_nr }} /* key */, CONFIG_LIBFLEXOS_COMP_HEAP_SIZE /* size */, flexos_comp{{ comp_nr }}_alloc);
diff --git a/kraft/sec/rules/gatereplacer.cocci.in b/kraft/sec/rules/gatereplacer.cocci.in
@@ -1,13 +1,65 @@
+@gatereplacer_return0_{{ rule_nr }}@
+identifier func;
+expression ret, lname;
+fresh identifier func_id = "{{ ept_id_prefix }}" ## func;
+@@
+- flexos_gate_r({{ lib_dest_name }}, ret, func);
++ {{ gate_r }}({{ comp_cur_nb }}, {{ comp_dest_nb }}, ret, func_id);
+
+@script:python@
+func_name << gatereplacer_return0_{{ rule_nr }}.func;
+@@
+fname = str(func_name)
+if fname not in entries:
+    entries[fname] = entry_cnt
+    entry_cnt += 1
+
 @gatereplacer_return{{ rule_nr }}@
+identifier func;
 expression list EL;
 expression ret, lname;
+fresh identifier func_id = "{{ ept_id_prefix }}" ## func;
+@@
+- flexos_gate_r({{ lib_dest_name }}, ret, func, EL);
++ {{ gate_r }}({{ comp_cur_nb }}, {{ comp_dest_nb }}, ret, func_id, EL);
+
+@script:python@
+func_name << gatereplacer_return{{ rule_nr }}.func;
 @@
-- flexos_gate_r({{ lib_dest_name }}, ret, EL);
-+ {{ gate_r }}({{ comp_cur_nb }}, {{ comp_dest_nb }}, ret, EL);
+fname = str(func_name)
+if fname not in entries:
+    entries[fname] = entry_cnt
+    entry_cnt += 1
+
+@gatereplacer_noreturn0_{{ rule_nr }}@
+identifier func;
+expression lname;
+fresh identifier func_id = "{{ ept_id_prefix }}" ## func;
+@@
+- flexos_gate({{ lib_dest_name }}, func);
++ {{ gate }}({{ comp_cur_nb }}, {{ comp_dest_nb }}, func_id);
+
+@script:python@
+func_name << gatereplacer_noreturn0_{{ rule_nr }}.func;
+@@
+fname = str(func_name)
+if fname not in entries:
+    entries[fname] = entry_cnt
+    entry_cnt += 1
 
 @gatereplacer_noreturn{{ rule_nr }}@
+identifier func;
 expression list EL;
 expression lname;
+fresh identifier func_id = "{{ ept_id_prefix }}" ## func;
+@@
+- flexos_gate({{ lib_dest_name }}, func, EL);
++ {{ gate }}({{ comp_cur_nb }}, {{ comp_dest_nb }}, func_id, EL);
+
+@script:python@
+func_name << gatereplacer_noreturn{{ rule_nr }}.func;
 @@
-- flexos_gate({{ lib_dest_name }}, EL);
-+ {{ gate }}({{ comp_cur_nb }}, {{ comp_dest_nb }}, EL);
+fname = str(func_name)
+if fname not in entries:
+    entries[fname] = entry_cnt
+    entry_cnt += 1