Bug#611390: Acknowledgement (linux-image-2.6.32-5-686: Asus WL-167g / rt2500usb regression: DHCP no longer possible)

[Sven Arvidsson <sa@whiz.se>]

tags 611390 patch
thanks

Got it!

The fix is 75f64dd54a185150ebfc45e99351c890d4a2252f "fallback to SW
encryption for TKIP+AES" a small patch which is easily applied to
2.6.32.

I'm not sure if TKIP+AES is an unusual combination, but if it is it
would explain why it went unnoticed for a while (and would make the
severity of this bug a little bit less).

I guess it might be a bit late to get this into Squeeze for the release,
but it would be great if it made it for one of the point releases.

-- 
Cheers,
Sven Arvidsson
http://www.whiz.se
PGP Key ID 760BDD22

commit 75f64dd54a185150ebfc45e99351c890d4a2252f
Author: Ondrej Zary <linux@rainbow-software.org>
Date:   Wed Jun 23 12:57:15 2010 +0200

    rt2500usb: fallback to SW encryption for TKIP+AES
    
    HW crypto in rt2500usb does not seem to support keys with different ciphers,
    which breaks TKIP+AES mode. Fall back to software encryption to fix it.
    
    This should fix long-standing problems with rt2500usb and WPA, such as:
    http://rt2x00.serialmonkey.com/phpBB/viewtopic.php?f=4&t=4834
    https://bugzilla.redhat.com/show_bug.cgi?id=484888
    
    Also tested that it does not break WEP, TKIP-only and AES-only modes.
    
    Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
    Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
    Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/rt2x00/rt2500usb.c b/drivers/net/wireless/rt2x00/rt2500usb.c
index 002db64..963238c 100644
--- a/drivers/net/wireless/rt2x00/rt2500usb.c
+++ b/drivers/net/wireless/rt2x00/rt2500usb.c
@@ -347,6 +347,7 @@ static int rt2500usb_config_key(struct rt2x00_dev *rt2x00dev,
 {
 	u32 mask;
 	u16 reg;
+	enum cipher curr_cipher;
 
 	if (crypto->cmd == SET_KEY) {
 		/*
@@ -357,6 +358,7 @@ static int rt2500usb_config_key(struct rt2x00_dev *rt2x00dev,
 		mask = TXRX_CSR0_KEY_ID.bit_mask;
 
 		rt2500usb_register_read(rt2x00dev, TXRX_CSR0, &reg);
+		curr_cipher = rt2x00_get_field16(reg, TXRX_CSR0_ALGORITHM);
 		reg &= mask;
 
 		if (reg && reg == mask)
@@ -365,6 +367,14 @@ static int rt2500usb_config_key(struct rt2x00_dev *rt2x00dev,
 		reg = rt2x00_get_field16(reg, TXRX_CSR0_KEY_ID);
 
 		key->hw_key_idx += reg ? ffz(reg) : 0;
+		/*
+		 * Hardware requires that all keys use the same cipher
+		 * (e.g. TKIP-only, AES-only, but not TKIP+AES).
+		 * If this is not the first key, compare the cipher with the
+		 * first one and fall back to SW crypto if not the same.
+		 */
+		if (key->hw_key_idx > 0 && crypto->cipher != curr_cipher)
+			return -EOPNOTSUPP;
 
 		rt2500usb_register_multiwrite(rt2x00dev, reg,
 					      crypto->key, sizeof(crypto->key));

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