Return-path: Received: from ey-out-2122.google.com ([74.125.78.26]:23121 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753526AbZHJKdN (ORCPT ); Mon, 10 Aug 2009 06:33:13 -0400 Message-ID: <4A7FF84C.7070708@gmail.com> Date: Mon, 10 Aug 2009 12:37:00 +0200 From: Roel Kluin MIME-Version: 1.0 To: Cyrill Gorcunov CC: Michael Buesch , Daniel Mack , "John W. Linville" , libertas-dev@lists.infradead.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Libertas: Association request to the driver failed References: <20090807191156.GS19257@buzzloop.caiaq.de> <20090809102417.GH13639@buzzloop.caiaq.de> <4A7EAED8.9090900@gmail.com> <200908091310.56919.mb@bu3sch.de> <20090809191359.GG4805@lenovo> In-Reply-To: <20090809191359.GG4805@lenovo> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: Several arrays were read before checking whether the index was within bounds. ARRAY_SIZE() should be used to determine the size of arrays. rates->rates has an arraysize of 1, so calling get_common_rates() with a rates_size of MAX_RATES (14) was causing reads out of bounds. tmp_size can increment at most to MAX_RATES * ARRAY_SIZE(lbs_bg_rates), so that should be the number of elements of tmp[]. Signed-off-by: Roel Kluin --- > | Is it a good idea to use dynamic stack arrays in the kernel? > | What about kmalloc for dynamic allocations? > | > | -- > | Greetings, Michael. > > I saw one pattern in trace code (not sure if it's > still there) but personally don't like dynamic > stack arrays (though at moment the max value > being passed into routine is known maybe just > use MAX_RATES instead of (*rates_size)?). Hmm? Good point. > -- Cyrill Thanks, I think there was another problem in lbs_associate(), the memcpy already affected rates->rates. Also in get_common_rates() I think we can safely move the memset/memcpy, originally after label done, upwards. The patch below, if correct, is to be applied after the revert Roel diff --git a/drivers/net/wireless/libertas/assoc.c b/drivers/net/wireless/libertas/assoc.c index b9b3741..ba0164a 100644 --- a/drivers/net/wireless/libertas/assoc.c +++ b/drivers/net/wireless/libertas/assoc.c @@ -1,6 +1,7 @@ /* Copyright (C) 2006, Red Hat, Inc. */ #include +#include #include #include #include @@ -43,41 +44,41 @@ static int get_common_rates(struct lbs_private *priv, u16 *rates_size) { u8 *card_rates = lbs_bg_rates; - size_t num_card_rates = sizeof(lbs_bg_rates); - int ret = 0, i, j; - u8 tmp[30]; + int i, j; + u8 tmp[MAX_RATES * ARRAY_SIZE(lbs_bg_rates)]; size_t tmp_size = 0; /* For each rate in card_rates that exists in rate1, copy to tmp */ - for (i = 0; card_rates[i] && (i < num_card_rates); i++) { - for (j = 0; rates[j] && (j < *rates_size); j++) { + for (i = 0; i < ARRAY_SIZE(lbs_bg_rates) && card_rates[i]; i++) { + for (j = 0; j < *rates_size && rates[j]; j++) { if (rates[j] == card_rates[i]) tmp[tmp_size++] = card_rates[i]; } } lbs_deb_hex(LBS_DEB_JOIN, "AP rates ", rates, *rates_size); - lbs_deb_hex(LBS_DEB_JOIN, "card rates ", card_rates, num_card_rates); + lbs_deb_hex(LBS_DEB_JOIN, "card rates ", card_rates, + ARRAY_SIZE(lbs_bg_rates)); lbs_deb_hex(LBS_DEB_JOIN, "common rates", tmp, tmp_size); lbs_deb_join("TX data rate 0x%02x\n", priv->cur_rate); + memset(rates, 0, *rates_size); + *rates_size = min_t(u16, tmp_size, *rates_size); + memcpy(rates, tmp, *rates_size); + if (!priv->enablehwauto) { for (i = 0; i < tmp_size; i++) { if (tmp[i] == priv->cur_rate) - goto done; + break; + } + if (i == tmp_size) { + lbs_pr_alert("Previously set fixed data rate %#x isn't " + "compatible with the network.\n", + priv->cur_rate); + return -1; } - lbs_pr_alert("Previously set fixed data rate %#x isn't " - "compatible with the network.\n", priv->cur_rate); - ret = -1; - goto done; } - ret = 0; - -done: - memset(rates, 0, *rates_size); - *rates_size = min_t(int, tmp_size, *rates_size); - memcpy(rates, tmp, *rates_size); - return ret; + return 0; } @@ -321,8 +322,8 @@ static int lbs_associate(struct lbs_private *priv, rates = (struct mrvl_ie_rates_param_set *) pos; rates->header.type = cpu_to_le16(TLV_TYPE_RATES); - memcpy(&rates->rates, &bss->rates, MAX_RATES); - tmplen = MAX_RATES; + tmplen = min_t(u16, ARRAY_SIZE(rates->rates), MAX_RATES); + memcpy(&rates->rates, &bss->rates, tmplen); if (get_common_rates(priv, rates->rates, &tmplen)) { ret = -1; goto done; @@ -598,7 +599,7 @@ static int lbs_adhoc_join(struct lbs_private *priv, /* Copy Data rates from the rates recorded in scan response */ memset(cmd.bss.rates, 0, sizeof(cmd.bss.rates)); - ratesize = min_t(u16, sizeof(cmd.bss.rates), MAX_RATES); + ratesize = min_t(u16, ARRAY_SIZE(cmd.bss.rates), MAX_RATES); memcpy(cmd.bss.rates, bss->rates, ratesize); if (get_common_rates(priv, cmd.bss.rates, &ratesize)) { lbs_deb_join("ADHOC_JOIN: get_common_rates returned error.\n");