[PATCH 1/2] Support python 3 in utils/key2pub.py.

[ahmed.taahir@gmail.com]

From: Taahir Ahmed <ahmed.taahir@gmail.com>

utils/key2pub.py can now be run under either python 2.7 or python 3.x.
This required some minor syntactical changes as well as switching from
M2Crypto to pycrypto, since M2Crypto doesn't support python 3.x.

In addition, some errors in the generated source file keys-ssl.h are
fixed:

  * The correct OpenSSL header for BN_ULONG is included.

  * The generated constants are given the 'ull' suffix to prevent
    warnings about constants that are too large.
---
 Makefile         |   2 +-
 utils/key2pub.py | 146 ++++++++++++++++++++++++++++---------------------------
 2 files changed, 75 insertions(+), 73 deletions(-)

diff --git a/Makefile b/Makefile
index a3ead30..65fc780 100644
--- a/Makefile
+++ b/Makefile
@@ -112,7 +112,7 @@ $(REG_BIN):
 keys-%.c: utils/key2pub.py $(wildcard $(PUBKEY_DIR)/*.pem)
 	$(NQ) '  GEN ' $@
 	$(NQ) '  Trusted pubkeys:' $(wildcard $(PUBKEY_DIR)/*.pem)
-	$(Q)./utils/key2pub.py --$* $(wildcard $(PUBKEY_DIR)/*.pem) $@
+	$(Q) python /utils/key2pub.py --$* $(wildcard $(PUBKEY_DIR)/*.pem) $@
 
 $(LIBREG): regdb.h reglib.h reglib.c
 	$(NQ) '  CC  ' $@
diff --git a/utils/key2pub.py b/utils/key2pub.py
index 3e84cd2..ff92748 100755
--- a/utils/key2pub.py
+++ b/utils/key2pub.py
@@ -1,126 +1,128 @@
 #!/usr/bin/env python
 
+import io
 import sys
 try:
-       from M2Crypto import RSA
-except ImportError, e:
-       sys.stderr.write('ERROR: Failed to import the "M2Crypto" module: %s\n' % e.message)
-       sys.stderr.write('Please install the "M2Crypto" Python module.\n')
-       sys.stderr.write('On Debian GNU/Linux the package is called "python-m2crypto".\n')
-       sys.exit(1)
+    from Crypto.PublicKey import RSA
+except ImportError as e:
+    sys.stderr.write('ERROR: Failed to import the "Crypto.PublicKey" module: %s\n' % e.message)
+    sys.stderr.write('Please install the "Crypto.PublicKey" Python module.\n')
+    sys.stderr.write('On Debian GNU/Linux the package is called "python-crypto".\n')
+    sys.exit(1)
+
+def bitwise_collect(value, radix_bits):
+    words = []
+    radix_mask = (1 << radix_bits) - 1
+    while value != 0:
+        words.append(value & radix_mask)
+        value >>= radix_bits
+    return words
 
 def print_ssl_64(output, name, val):
-    while val[0] == '\0':
-        val = val[1:]
-    while len(val) % 8:
-        val = '\0' + val
-    vnew = []
-    while len(val):
-        vnew.append((val[0], val[1], val[2], val[3], val[4], val[5], val[6], val[7]))
-        val = val[8:]
-    vnew.reverse()
-    output.write('static BN_ULONG %s[%d] = {\n' % (name, len(vnew)))
+    # OpenSSL expects 64-bit words given least-significant-word first.
+    vwords = bitwise_collect(val, 64)
+
+    output.write(u'static BN_ULONG {}[] = {{\n'.format(name))
     idx = 0
-    for v1, v2, v3, v4, v5, v6, v7, v8 in vnew:
+    for vword in vwords:
         if not idx:
-            output.write('\t')
-        output.write('0x%.2x%.2x%.2x%.2x%.2x%.2x%.2x%.2x, ' % (ord(v1), ord(v2), ord(v3), ord(v4), ord(v5), ord(v6), ord(v7), ord(v8)))
+            output.write(u'\t')
+        output.write(u'0x{:016x}ULL, '.format(vword))
         idx += 1
         if idx == 2:
             idx = 0
-            output.write('\n')
+            output.write(u'\n')
     if idx:
-        output.write('\n')
-    output.write('};\n\n')
+        output.write(u'\n')
+    output.write(u'};\n\n')
 
 def print_ssl_32(output, name, val):
-    while val[0] == '\0':
-        val = val[1:]
-    while len(val) % 4:
-        val = '\0' + val
-    vnew = []
-    while len(val):
-        vnew.append((val[0], val[1], val[2], val[3], ))
-        val = val[4:]
-    vnew.reverse()
-    output.write('static BN_ULONG %s[%d] = {\n' % (name, len(vnew)))
+    # OpenSSL expects 32-bit words given least-significant-word first.
+    vwords = bitwise_collect(val, 32)
+
+    output.write(u'static BN_ULONG {}[] = {{\n'.format(name))
     idx = 0
-    for v1, v2, v3, v4 in vnew:
+    for vword in vwords:
         if not idx:
-            output.write('\t')
-        output.write('0x%.2x%.2x%.2x%.2x, ' % (ord(v1), ord(v2), ord(v3), ord(v4)))
+            output.write(u'\t')
+        output.write(u'0x{:08x}, '.format(vword))
         idx += 1
         if idx == 4:
             idx = 0
-            output.write('\n')
+            output.write(u'\n')
     if idx:
-        output.write('\n')
-    output.write('};\n\n')
+        output.write(u'\n')
+    output.write(u'};\n\n')
 
 def print_ssl(output, name, val):
+
+    output.write(u'#include <stdint.h>\n')
+    output.write(u'#include <openssl/bn.h>\n')
+
     import struct
-    output.write('#include <stdint.h>\n')
     if len(struct.pack('@L', 0)) == 8:
         return print_ssl_64(output, name, val)
     else:
         return print_ssl_32(output, name, val)
 
 def print_ssl_keys(output, n):
-    output.write(r'''
+    output.write(u'''
 struct pubkey {
 	struct bignum_st e, n;
 };
 
-#define KEY(data) {				\
-	.d = data,				\
-	.top = sizeof(data)/sizeof(data[0]),	\
+#define KEY(data) {                          \\
+	.d = data,                           \\
+	.top = sizeof(data)/sizeof(data[0]), \\
 }
 
-#define KEYS(e,n)	{ KEY(e), KEY(n), }
+#define KEYS(e,n)    { KEY(e), KEY(n), }
 
 static struct pubkey keys[] = {
 ''')
     for n in xrange(n + 1):
-        output.write('	KEYS(e_%d, n_%d),\n' % (n, n))
-    output.write('};\n')
+        output.write(u'	KEYS(e_{0}, n_{0}),\n'.format(n))
+    output.write(u'};\n')
     pass
 
 def print_gcrypt(output, name, val):
-    output.write('#include <stdint.h>\n')
-    while val[0] == '\0':
-        val = val[1:]
-    output.write('static const uint8_t %s[%d] = {\n' % (name, len(val)))
+    # gcrypt expects 8-bit words most-significant-word first
+    vwords = bitwise_collect(val, 8)
+    vwords.reverse()
+    
+    output.write(u'#include <stdint.h>\n')
+    output.write(u'static const uint8_t %s[%d] = {\n' % (name, len(vwords)))
     idx = 0
-    for v in val:
+    for vword in vwords:
         if not idx:
-            output.write('\t')
-        output.write('0x%.2x, ' % ord(v))
+            output.write(u'\t')
+        output.write(u'0x{:02x}, '.format(vword))
         idx += 1
         if idx == 8:
             idx = 0
-            output.write('\n')
+            output.write(u'\n')
     if idx:
-        output.write('\n')
-    output.write('};\n\n')
+        output.write(u'\n')
+    output.write(u'};\n\n')
 
 def print_gcrypt_keys(output, n):
-    output.write(r'''
+    output.write(u'''
 struct key_params {
 	const uint8_t *e, *n;
 	uint32_t len_e, len_n;
 };
 
-#define KEYS(_e, _n) {			\
-	.e = _e, .len_e = sizeof(_e),	\
-	.n = _n, .len_n = sizeof(_n),	\
+#define KEYS(_e, _n) {                \\
+	.e = _e, .len_e = sizeof(_e), \\
+	.n = _n, .len_n = sizeof(_n), \\
 }
 
 static const struct key_params keys[] = {
 ''')
-    for n in xrange(n + 1):
-        output.write('	KEYS(e_%d, n_%d),\n' % (n, n))
-    output.write('};\n')
-    
+    for n in range(n + 1):
+        output.write(u'	KEYS(e_{0}, n_{0}),\n'.format(n))
+    output.write(u'};\n')
+
 
 modes = {
     '--ssl': (print_ssl, print_ssl_keys),
@@ -135,21 +137,21 @@ except IndexError:
     mode = None
 
 if not mode in modes:
-    print 'Usage: %s [%s] input-file... output-file' % (sys.argv[0], '|'.join(modes.keys()))
+    print('Usage: {} [{}] input-file... output-file'.format(sys.argv[0], '|'.join(modes.keys())))
     sys.exit(2)
 
-output = open(outfile, 'w')
+output = io.open(outfile, 'w')
 
 # load key
 idx = 0
 for f in files:
-    try:
-        key = RSA.load_pub_key(f)
-    except RSA.RSAError:
-        key = RSA.load_key(f)
 
-    modes[mode][0](output, 'e_%d' % idx, key.e[4:])
-    modes[mode][0](output, 'n_%d' % idx, key.n[4:])
+    key_contents = io.open(f, 'rb').read()
+    key = RSA.importKey(key_contents)
+
+    modes[mode][0](output, 'e_{}'.format(idx), key.e)
+    modes[mode][0](output, 'n_{}'.format(idx), key.n)
+
     idx += 1
 
 modes[mode][1](output, idx - 1)
-- 
2.3.6