From patchwork Thu Sep 5 15:04:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 825889 Received: from forward204d.mail.yandex.net (forward204d.mail.yandex.net [178.154.239.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 302E62F870; Thu, 5 Sep 2024 15:04:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.217 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725548698; cv=none; b=K8f9YV6WvcQtss4ACQp6wjSNt0Fe1OOnh4o1wgw+xZSpPBiUOhoC4yZounxLJd7hUDSPh+x77BioDlhOV9lzKPYVwpZ7LICNXJvKehQFptiijp1VATLzGt0Pb4K8o89wlN17JgoqAMGxVvTU8vygKIfaQ0+GOf2buNCcJ+6M2c0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725548698; c=relaxed/simple; bh=vruifMt9jJV41i0HP2Eom4MO7+B2BqcVmvMVRs8z1rA=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ri8JmBH3RE64/XCUejPDIen5Auf3J1c4AkQDx8Nsn8d9OYX9XoMq4sr/zlptAfgkqFrZlqgPEWJ07wxYpdeypRwL2fiEnELRlhu4TrunWC1FaRiwW9h/9bIub+SYlqYHZ1MKVfrWM1aukAELm8LVekNxHdxJQSilq+uT9ZaKINU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru; spf=pass smtp.mailfrom=yandex.ru; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b=vRTFRtqy; arc=none smtp.client-ip=178.154.239.217 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=yandex.ru Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b="vRTFRtqy" Received: from forward100d.mail.yandex.net (forward100d.mail.yandex.net [IPv6:2a02:6b8:c41:1300:1:45:d181:d100]) by forward204d.mail.yandex.net (Yandex) with ESMTPS id CDFCB616B4; Thu, 5 Sep 2024 18:04:51 +0300 (MSK) Received: from mail-nwsmtp-smtp-production-main-42.klg.yp-c.yandex.net (mail-nwsmtp-smtp-production-main-42.klg.yp-c.yandex.net [IPv6:2a02:6b8:c42:4749:0:640:7137:0]) by forward100d.mail.yandex.net (Yandex) with ESMTPS id D2B72608EC; Thu, 5 Sep 2024 18:04:43 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-42.klg.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id g4fVLnGMoeA0-s7lnmQ6c; Thu, 05 Sep 2024 18:04:42 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1725548682; bh=BRAkwj4fTjxySbhtRhCHYyGmhowE49Q+BsiYDKJ038E=; h=Message-ID:Date:Cc:Subject:To:From; b=vRTFRtqy/YpKJ9h4hL/hN3PnssvFkz382LJM3s+6FW1MyI2KlPeNlRtByh6Tx2Tnk nG/k/8ah6diAKXN7LUl/pfuS+jS7SZxQpTee9cB5AD+YbaRPqn40sXRAE2hJ0qUWxH lV7GPyvVzBaCJGJzUY7HeiT+CdvfrdVHLnQFF+ng= Authentication-Results: mail-nwsmtp-smtp-production-main-42.klg.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Johannes Berg Cc: Kalle Valo , linux-wireless@vger.kernel.org, Kees Cook , linux-hardening@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov Subject: [PATCH] wifi: cfg80211: fix UBSAN noise in cfg80211_wext_siwscan() Date: Thu, 5 Sep 2024 18:04:00 +0300 Message-ID: <20240905150400.126386-1-dmantipov@yandex.ru> X-Mailer: git-send-email 2.46.0 Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Looking at https://syzkaller.appspot.com/bug?extid=1a3986bbd3169c307819 and running reproducer with CONFIG_UBSAN_BOUNDS, I've noticed the following: [ T4985] UBSAN: array-index-out-of-bounds in net/wireless/scan.c:3479:25 [ T4985] index 164 is out of range for type 'struct ieee80211_channel *[]' <...skipped...> [ T4985] Call Trace: [ T4985] [ T4985] dump_stack_lvl+0x1c2/0x2a0 [ T4985] ? __pfx_dump_stack_lvl+0x10/0x10 [ T4985] ? __pfx__printk+0x10/0x10 [ T4985] __ubsan_handle_out_of_bounds+0x127/0x150 [ T4985] cfg80211_wext_siwscan+0x11a4/0x1260 <...the rest is not too useful...> Even if we do 'creq->n_channels = n_channels' before 'creq->ssids = (void *)&creq->channels[n_channels]', UBSAN treats the latter as off-by-one error. Fix this by using pointer arithmetic rather than an expression with explicit array indexing and use convenient 'struct_size()' to simplify the math here and in 'kzalloc()' above. Fixes: 5ba63533bbf6 ("cfg80211: fix alignment problem in scan request") Signed-off-by: Dmitry Antipov Reviewed-by: Kees Cook --- net/wireless/scan.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 64eeed82d43d..d747d5f63278 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -3467,8 +3467,8 @@ int cfg80211_wext_siwscan(struct net_device *dev, n_channels = ieee80211_get_num_supported_channels(wiphy); } - creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) + - n_channels * sizeof(void *), + creq = kzalloc(struct_size(creq, channels, n_channels) + + sizeof(struct cfg80211_ssid), GFP_ATOMIC); if (!creq) return -ENOMEM; @@ -3476,7 +3476,7 @@ int cfg80211_wext_siwscan(struct net_device *dev, creq->wiphy = wiphy; creq->wdev = dev->ieee80211_ptr; /* SSIDs come after channels */ - creq->ssids = (void *)&creq->channels[n_channels]; + creq->ssids = (void *)creq + struct_size(creq, channels, n_channels); creq->n_channels = n_channels; creq->n_ssids = 1; creq->scan_start = jiffies;