Fix bug caused by 1mod8 compatibility issue.

In the switch from v3, we bind identities in the message MAC
instead of doing the 1mod8 trick.  Since identity keys were
never set as 1mod8, it seemed like we could just remove it.

However, PreKeys are durable.  If an old client upgrades to v3,
it has a bunch of keys that *were* set to 1mod8 floating around.
The Curve25519 donna code re-sets the private key bits on every
operation, which results in a different key, and breaks the output
of an agreement.

So now we don't intentionally generate keys with 1mod8, but we
have to remove the donna code to honor existing 1mod8 keys for
the rest of time.  Trevor is squarely to blame.

// FREEBIE
This commit is contained in:
Moxie Marlinspike 2014-10-23 16:02:37 -07:00
parent 9dfaf19516
commit e7b6a852c5
7 changed files with 31 additions and 29 deletions

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@ -857,9 +857,9 @@ curve25519_donna(u8 *mypublic, const u8 *secret, const u8 *basepoint) {
int i; int i;
for (i = 0; i < 32; ++i) e[i] = secret[i]; for (i = 0; i < 32; ++i) e[i] = secret[i];
e[0] &= 248; // e[0] &= 248;
e[31] &= 127; // e[31] &= 127;
e[31] |= 64; // e[31] |= 64;
fexpand(bp, basepoint); fexpand(bp, basepoint);
cmult(x, z, e, bp); cmult(x, z, e, bp);

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@ -90,12 +90,13 @@ public class RatchetingSessionTest extends AndroidTestCase {
(byte) 0xee, (byte) 0xfc, (byte) 0xb4, (byte) 0x2b, (byte) 0xee, (byte) 0xfc, (byte) 0xb4, (byte) 0x2b,
(byte) 0x4a}; (byte) 0x4a};
byte[] senderChain = {(byte)0x33, (byte)0xe9, (byte)0x46, (byte)0x5e, (byte)0x88, (byte)0x92, byte[] senderChain = {(byte)0xd2, (byte)0x2f, (byte)0xd5, (byte)0x6d, (byte)0x3f,
(byte)0x2b, (byte)0x51, (byte)0xa6, (byte)0x76, (byte)0xaf, (byte)0xba, (byte)0xec, (byte)0x81, (byte)0x9c, (byte)0xf4, (byte)0xc3,
(byte)0x03, (byte)0xf2, (byte)0x27, (byte)0x58, (byte)0xee, (byte)0xe1, (byte)0xd5, (byte)0x0c, (byte)0x56, (byte)0xed, (byte)0xfb,
(byte)0xef, (byte)0x15, (byte)0xb0, (byte)0x28, (byte)0x39, (byte)0x0d, (byte)0x1c, (byte)0x28, (byte)0x0a, (byte)0x1b, (byte)0x31,
(byte)0x70, (byte)0x76, (byte)0xc7, (byte)0xc7, (byte)0x09, (byte)0xef, (byte)0x96, (byte)0x45, (byte)0x37, (byte)0xf1, (byte)0xd1,
(byte)0x5d, (byte)0x8b}; (byte)0x61, (byte)0xe1, (byte)0xc9, (byte)0x31, (byte)0x48,
(byte)0xe3, (byte)0x6b};
IdentityKey bobIdentityKeyPublic = new IdentityKey(bobIdentityPublic, 0); IdentityKey bobIdentityKeyPublic = new IdentityKey(bobIdentityPublic, 0);
ECPrivateKey bobIdentityKeyPrivate = Curve.decodePrivatePoint(bobIdentityPrivate); ECPrivateKey bobIdentityKeyPrivate = Curve.decodePrivatePoint(bobIdentityPrivate);
@ -192,12 +193,13 @@ public class RatchetingSessionTest extends AndroidTestCase {
(byte) 0xeb, (byte) 0x0a, (byte) 0x6f, (byte) 0x4f, (byte) 0x5f, (byte) 0xeb, (byte) 0x0a, (byte) 0x6f, (byte) 0x4f, (byte) 0x5f,
(byte) 0x8f, (byte) 0x58}; (byte) 0x8f, (byte) 0x58};
byte[] receiverChain = {(byte)0x68, (byte)0x4a, (byte)0xc5, (byte)0x15, (byte)0xc9, (byte)0x14, byte[] receiverChain = {(byte) 0xd2, (byte) 0x2f, (byte) 0xd5, (byte) 0x6d, (byte) 0x3f,
(byte)0x45, (byte)0xf7, (byte)0xa0, (byte)0xc9, (byte)0x3c, (byte)0x39, (byte) 0xec, (byte) 0x81, (byte) 0x9c, (byte) 0xf4, (byte) 0xc3,
(byte)0xf7, (byte)0xe6, (byte)0xa1, (byte)0x7f, (byte)0xa0, (byte)0x8e, (byte) 0xd5, (byte) 0x0c, (byte) 0x56, (byte) 0xed, (byte) 0xfb,
(byte)0x04, (byte)0x62, (byte)0xf1, (byte)0x50, (byte)0xe5, (byte)0xac, (byte) 0x1c, (byte) 0x28, (byte) 0x0a, (byte) 0x1b, (byte) 0x31,
(byte)0x60, (byte)0x71, (byte)0x78, (byte)0xc1, (byte)0xa5, (byte)0xd2, (byte) 0x96, (byte) 0x45, (byte) 0x37, (byte) 0xf1, (byte) 0xd1,
(byte)0xc7, (byte)0xd6}; (byte) 0x61, (byte) 0xe1, (byte) 0xc9, (byte) 0x31, (byte) 0x48,
(byte) 0xe3, (byte) 0x6b};
IdentityKey bobIdentityKey = new IdentityKey(bobIdentityPublic, 0); IdentityKey bobIdentityKey = new IdentityKey(bobIdentityPublic, 0);
ECPublicKey bobEphemeralPublicKey = Curve.decodePoint(bobPublic, 0); ECPublicKey bobEphemeralPublicKey = Curve.decodePoint(bobPublic, 0);

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@ -50,21 +50,21 @@ public class RootKeyTest extends AndroidTestCase {
(byte) 0x95, (byte) 0x55, (byte) 0xe8, (byte) 0x47, (byte) 0x57, (byte) 0x95, (byte) 0x55, (byte) 0xe8, (byte) 0x47, (byte) 0x57,
(byte) 0x70, (byte) 0x8a, (byte) 0x30}; (byte) 0x70, (byte) 0x8a, (byte) 0x30};
byte[] nextRoot = {(byte)0x67, (byte)0x46, (byte)0x77, (byte)0x65, (byte)0x21, byte[] nextRoot = {(byte) 0xb1, (byte) 0x14, (byte) 0xf5, (byte) 0xde, (byte) 0x28,
(byte)0x04, (byte)0xe8, (byte)0x64, (byte)0xd0, (byte)0x7c, (byte) 0x01, (byte) 0x19, (byte) 0x85, (byte) 0xe6, (byte) 0xeb,
(byte)0x54, (byte)0x33, (byte)0xef, (byte)0xaa, (byte)0x59, (byte) 0xa2, (byte) 0x5d, (byte) 0x50, (byte) 0xe7, (byte) 0xec,
(byte)0x25, (byte)0xed, (byte)0x43, (byte)0x67, (byte)0xd6, (byte) 0x41, (byte) 0xa9, (byte) 0xb0, (byte) 0x2f, (byte) 0x56,
(byte)0xb2, (byte)0x5a, (byte)0xaf, (byte)0xe6, (byte)0x99, (byte) 0x93, (byte) 0xc5, (byte) 0xc7, (byte) 0x88, (byte) 0xa6,
(byte)0x1d, (byte)0xef, (byte)0x5c, (byte)0x7f, (byte)0x0f, (byte) 0x3a, (byte) 0x06, (byte) 0xd2, (byte) 0x12, (byte) 0xa2,
(byte)0xb8, (byte)0x6f}; (byte) 0xf7, (byte) 0x31};
byte[] nextChain = {(byte)0xfa, (byte)0xed, (byte)0x7f, (byte)0xb2, (byte)0xc3, byte[] nextChain = {(byte) 0x9d, (byte) 0x7d, (byte) 0x24, (byte) 0x69, (byte) 0xbc,
(byte)0xe6, (byte)0xf6, (byte)0x06, (byte)0xfc, (byte)0xbf, (byte) 0x9a, (byte) 0xe5, (byte) 0x3e, (byte) 0xe9, (byte) 0x80,
(byte)0x26, (byte)0x64, (byte)0x6c, (byte)0xf2, (byte)0x68, (byte) 0x5a, (byte) 0xa3, (byte) 0x26, (byte) 0x4d, (byte) 0x24,
(byte)0xad, (byte)0x49, (byte)0x58, (byte)0x9f, (byte)0xcb, (byte) 0x99, (byte) 0xa3, (byte) 0xac, (byte) 0xe8, (byte) 0x0f,
(byte)0xde, (byte)0x01, (byte)0xc1, (byte)0x26, (byte)0x75, (byte) 0x4c, (byte) 0xca, (byte) 0xe2, (byte) 0xda, (byte) 0x13,
(byte)0xe5, (byte)0xe8, (byte)0x22, (byte)0xa7, (byte)0xe3, (byte) 0x43, (byte) 0x0c, (byte) 0x5c, (byte) 0x55, (byte) 0xb5,
(byte)0x35, (byte)0xd1}; (byte) 0xca, (byte) 0x5f};
ECPublicKey alicePublicKey = Curve.decodePoint(alicePublic, 0); ECPublicKey alicePublicKey = Curve.decodePoint(alicePublic, 0);
ECPrivateKey alicePrivateKey = Curve.decodePrivatePoint(alicePrivate); ECPrivateKey alicePrivateKey = Curve.decodePrivatePoint(alicePrivate);