diff -r 5c09e1c57200 Lib/platform.py
--- a/Lib/platform.py	Wed Mar 20 20:16:47 2013 +0100
+++ b/Lib/platform.py	Mon Mar 25 11:57:44 2013 -0700
@@ -129,6 +129,9 @@
         # Standard Unix uses /dev/null
         DEV_NULL = '/dev/null'
 
+# Directory to search for configuration information on Unix
+_UNIXCONFDIR = '/etc'
+
 ### Platform specific APIs
 
 _libc_search = re.compile(b'(__libc_init)'
@@ -315,15 +318,17 @@
 
     """
     try:
-        etc = os.listdir('/etc')
+        etc = os.listdir(_UNIXCONFDIR)
     except OSError:
         # Probably not a Unix system
-        return distname,version,id
+        return distname, version, id
+
+    # Try to find a file containing a distribution's release information
     etc.sort()
-    for file in etc:
-        m = _release_filename.match(file)
+    for filename in etc:
+        m = _release_filename.match(filename)
         if m is not None:
-            _distname,dummy = m.groups()
+            _distname, dummy = m.groups()
             if _distname in supported_dists:
                 distname = _distname
                 break
@@ -331,7 +336,8 @@
         return _dist_try_harder(distname,version,id)
 
     # Read the first line
-    with open('/etc/'+file, 'r') as f:
+    with open(os.path.join(_UNIXCONFDIR, filename), 'r', encoding='utf-8',
+                errors='surrogateescape') as f:
         firstline = f.readline()
     _distname, _version, _id = _parse_release_file(firstline)
 
diff -r 5c09e1c57200 Lib/test/test_platform.py
--- a/Lib/test/test_platform.py	Wed Mar 20 20:16:47 2013 +0100
+++ b/Lib/test/test_platform.py	Mon Mar 25 11:57:44 2013 -0700
@@ -1,10 +1,14 @@
+import locale
 import os
 import platform
 import subprocess
 import sys
+import tempfile
 import unittest
 import warnings
 
+from unittest.mock import MagicMock, patch
+
 from test import support
 
 class PlatformTest(unittest.TestCase):
@@ -37,6 +41,55 @@
             for terse in (False, True):
                 res = platform.platform(aliased, terse)
 
+    def test_dist_with_utf8(self):
+        # Test reading the platform information with a variety of "odd" locale
+        # settings and utf-8 encodings of the files.
+
+        # Expectation:
+        # utf8_data will come out as utf8
+        # locale will have no effect on the outcome
+
+        with tempfile.TemporaryDirectory() as d:
+            utf8_data_directory = d
+            f = open(os.path.join(d, 'fedora-release'), 'wb')
+            f.write(self.release_string.encode('utf-8'))
+            f.close()
+
+            # The linux_distribution function reads from a file so we have to
+            # mock out the directory to look for that file in
+            with patch('platform._UNIXCONFDIR', d):
+                for temp_locale in ('C', 'pt_BR.UTF8', 'pt_BR.ISO8859-1'):
+                    locale.setlocale(locale.LC_ALL, temp_locale)
+                    self.assertEqual(platform.dist(),
+                                    self.parsed_release_string)
+
+                locale.resetlocale()
+
+    def test_dist_with_latin1(self):
+        # Test reading the platform information with a variety of "odd" locale
+        # settings and latin1 encodings of the files.  (Want to catch
+        # tracebacks in unicode handling and unknown encodings of that file)
+
+        # Expectations:
+        # latin1_data will be mangled with some surrogateescapes
+        # locale will have no effect on the outcome
+
+        with tempfile.TemporaryDirectory() as d:
+            latin1_data_directory = d
+            f = open(os.path.join(d, 'fedora-release'), 'wb')
+            f.write(self.release_string.encode('latin-1'))
+            f.close()
+
+            # The linux_distribution function reads from a file so we have to
+            # mock out the file that will be found by that
+            with patch('platform._UNIXCONFDIR', d):
+                for temp_locale in ('C', 'pt_BR.UTF8', 'pt_BR.ISO8859-1'):
+                    locale.setlocale(locale.LC_ALL, temp_locale)
+                    self.assertTrue(platform.dist(),
+                                self.parsed_mangled_latin1_release_as_utf8)
+
+                locale.resetlocale()
+
     def test_system(self):
         res = platform.system()
 
@@ -60,6 +113,12 @@
         self.save_mercurial = sys._mercurial
         self.save_platform = sys.platform
 
+        # data for testing dist with non-ascii encodings
+        self.release_string = "Fedora release 19 (Schrödinger's Cat)\n"
+        self.parsed_release_string = ("fedora", "19", "Schrödinger's Cat")
+        self.parsed_mangled_latin1_release_as_utf8 = ("fedora", "19",
+                                                      "Schr\udcf6dinger's_Cat")
+
     def tearDown(self):
         sys.version = self.save_version
         sys._mercurial = self.save_mercurial
diff -r 5c09e1c57200 Misc/NEWS
--- a/Misc/NEWS	Wed Mar 20 20:16:47 2013 +0100
+++ b/Misc/NEWS	Mon Mar 25 11:57:44 2013 -0700
@@ -292,6 +292,9 @@
 Library
 -------
 
+- Issue #17429: Fix a UnicodeDecodeError when platform.platform() reads the os
+  release information from a file that contains non-ascii characters.
+
 - Issue #16997: unittest.TestCase now provides a subTest() context manager
   to procedurally generate, in an easy way, small test instances.