Use elftools in rpath

Signed-off-by: Kyle Keen <keenerd@gmail.com>

1 files changed, 19 insertions, 36 deletions

diff --git a/Namcap/rules/rpath.py b/Namcap/rules/rpath.py
index f8e918f..51b2a15 100644
--- a/Namcap/rules/rpath.py
+++ b/Namcap/rules/rpath.py
@@ -17,37 +17,28 @@
 #   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #
 
-import os, subprocess, re
-import tempfile
-from Namcap.util import is_elf, clean_filename
+from Namcap.util import is_elf
 from Namcap.ruleclass import *
 
+from elftools.elf.elffile import ELFFile
+from elftools.elf.dynamic import DynamicSection
+
 allowed = ['/usr/lib', '/usr/lib32', '/lib', '$ORIGIN', '${ORIGIN}']
 allowed_toplevels = [s + '/' for s in allowed]
 warn = ['/usr/local/lib']
-libpath = re.compile('Library rpath: \[(.*)\]')
-
-def get_rpaths(filename):
-	p = subprocess.Popen(["readelf", "-d", filename],
-		env={'LANG': 'C'},
-		stdout=subprocess.PIPE,
-		stderr=subprocess.PIPE)
-	var = p.communicate()
-	if p.returncode != 0:
-		raise IOError("unable to read ELF file")
 
-	for j in var[0].decode('ascii').splitlines():
-		n = libpath.search(j)
-		# Is this a Library rpath: line?
-		if n is None:
+def get_rpaths(fileobj):
+	elffile = ELFFile(fileobj)
+	for section in elffile.iter_sections():
+		if not isinstance(section, DynamicSection):
 			continue
-
-		if ":" in n.group(1):
-			rpaths = n.group(1).split(':')
-		else:
-			rpaths = [n.group(1)]
-		for path in rpaths:
-			yield path
+		for tag in section.iter_tags():
+			if tag.entry.d_tag != 'DT_RPATH':
+				continue
+			rpaths = tag.rpath.decode('ascii')
+			rpaths = rpaths.split(':')
+			for path in rpaths:
+				yield path
 
 class package(TarballRule):
 	name = "rpath"
@@ -58,18 +49,11 @@ class package(TarballRule):
 				continue
 
 			# is it an ELF file ?
-			if not is_elf(tar.extractfile(entry)):
-				continue # not an ELF file
-			f = tar.extractfile(entry)
-			elf = f.read()
-			f.close()
-
-			# write it to a temporary file
-			f = tempfile.NamedTemporaryFile(delete = False)
-			f.write(elf)
-			f.close()
+			fileobj = tar.extractfile(entry)
+			if not is_elf(fileobj):
+				continue
 
-			for path in get_rpaths(f.name):
+			for path in get_rpaths(fileobj):
 				path_ok = path in allowed
 				for allowed_toplevel in allowed_toplevels:
 					if path.startswith(allowed_toplevel):
@@ -83,6 +67,5 @@ class package(TarballRule):
 					self.warnings.append(("insecure-rpath %s %s",
 						(path, entry.name)))
 
-			os.unlink(f.name)
 
 # vim: set ts=4 sw=4 noet: