From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-gw1-out.broadcom.com ([216.31.210.62]:59143 "EHLO mail-gw1-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751907AbaLRNBw (ORCPT ); Thu, 18 Dec 2014 08:01:52 -0500 Message-ID: <5492D03A.9020004@broadcom.com> (sfid-20141218_140203_159685_2132E239) Date: Thu, 18 Dec 2014 14:01:46 +0100 From: Arend van Spriel MIME-Version: 1.0 To: Brian Norris CC: "John W. Linville" , Kalle Valo , "David S. Miller" , "Brett Rudley" , "Franky (Zhenhui) Lin" , Hante Meuleman , , , Subject: Re: [PATCH] brcmsmac: don't leak kernel memory via printk() References: <1418204358-8357-1-git-send-email-computersforpeace@gmail.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12/18/14 07:32, Brian Norris wrote: > + others [1] > > On Wed, Dec 10, 2014 at 1:39 AM, Brian Norris > wrote: >> Debug code prints the fifo name via custom dev_warn() wrappers. The >> fifo_names array is only non-zero when debugging is manually enabled, >> which is all well and good. However, it's *not* good that this array >> uses zero-length arrays in the non-debug case, and so it doesn't >> actually have any memory allocated to it. This means that as far as we >> know, fifo_names[i] actually points to garbage memory. >> >> I've seen this in my log: >> >> [ 4601.205511] brcmsmac bcma0:1: wl0: brcms_c_d11hdrs_mac80211: �GeL txop exceeded phylen 137/256 dur 1602/1504 >> >> So let's give this array space enough to fill it with a NULL byte. >> >> Signed-off-by: Brian Norris >> Cc: Brett Rudley >> Cc: Arend van Spriel >> Cc: "Franky (Zhenhui) Lin" >> Cc: Hante Meuleman >> Cc: "John W. Linville" >> Cc: linux-wireless@vger.kernel.org >> Cc: brcm80211-dev-list@broadcom.com >> Cc: netdev@vger.kernel.org > > BTW, I guess this qualifies as a security hole, albeit a small one. > Should this be CC: stable@vger.kernel.org? I have no strong opinion on this, but I guess. Feel free to do so. Regards, Arend >> --- >> drivers/net/wireless/brcm80211/brcmsmac/main.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/wireless/brcm80211/brcmsmac/main.c b/drivers/net/wireless/brcm80211/brcmsmac/main.c >> index 1b474828d5b8..aed0c948dce8 100644 >> --- a/drivers/net/wireless/brcm80211/brcmsmac/main.c >> +++ b/drivers/net/wireless/brcm80211/brcmsmac/main.c >> @@ -316,7 +316,7 @@ static const u16 xmtfifo_sz[][NFIFO] = { >> static const char * const fifo_names[] = { >> "AC_BK", "AC_BE", "AC_VI", "AC_VO", "BCMC", "ATIM" }; >> #else >> -static const char fifo_names[6][0]; >> +static const char fifo_names[6][1]; >> #endif >> >> #ifdef DEBUG > > Brian > > [1] http://lwn.net/Articles/626689/