scripts/spdxcheck.py: always open files in binary mode

commit 3a6ab5c7dc114057fd67750e308e1745dafc0e6a upstream.

The spdxcheck script currently falls over when confronted with a binary
file (such as Documentation/logo.gif).  To avoid that, always open files
in binary mode and decode line-by-line, ignoring encoding errors.

One tricky case is when piping data into the script and reading it from
standard input.  By default, standard input will be opened in text mode,
so we need to reopen it in binary mode.

The breakage only happens with python3 and results in a
UnicodeDecodeError (according to Uwe).

Link: http://lkml.kernel.org/r/20181212131210.28024-1-thierry.reding@gmail.com
Fixes: 6f4d29df66ac ("scripts/spdxcheck.py: make python3 compliant")
Signed-off-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NJeremy Cline <jcline@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joe Perches <joe@perches.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

scripts/spdxcheck.py

@@ -168,6 +168,7 @@ class id_parser(object):
         self.curline = 0
         try:
             for line in fd:
+                line = line.decode(locale.getpreferredencoding(False), errors='ignore')
                 self.curline += 1
                 if self.curline > maxlines:
                     break
@@ -249,12 +250,13 @@ if __name__ == '__main__':
 
     try:
         if len(args.path) and args.path[0] == '-':
-            parser.parse_lines(sys.stdin, args.maxlines, '-')
+            stdin = os.fdopen(sys.stdin.fileno(), 'rb')
+            parser.parse_lines(stdin, args.maxlines, '-')
         else:
             if args.path:
                 for p in args.path:
                     if os.path.isfile(p):
-                        parser.parse_lines(open(p), args.maxlines, p)
+                        parser.parse_lines(open(p, 'rb'), args.maxlines, p)
                     elif os.path.isdir(p):
                         scan_git_subtree(repo.head.reference.commit.tree, p)
                     else: