From patchwork Tue Dec 7 14:29:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 521896 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AD6AC433F5 for ; Tue, 7 Dec 2021 14:30:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233367AbhLGOeF (ORCPT ); Tue, 7 Dec 2021 09:34:05 -0500 Received: from dvalin.narfation.org ([213.160.73.56]:58080 "EHLO dvalin.narfation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232417AbhLGOeF (ORCPT ); Tue, 7 Dec 2021 09:34:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1638887433; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=M/6VW7i7W+xthc4rrARhEy/BbZdY9QLtRROjfHQerbo=; b=UzoljNDWkgQnQwRzMb4XekfUMSiDgAsdMPdJhoqkHCuIkUdlVBnh/SqIbGLiNg8hBSNC9Y BL6JAUVjz6FgCYWG5guqnc4QvA9CdSuaaiVl/4WStufgvwPnxaSNgHMubcSDjkjsDb10U5 HTORV6os2TbTUmEcrHvUZzHqk74QZ0Y= From: Sven Eckelmann To: ath11k@lists.infradead.org Cc: linux-wireless@vger.kernel.org, Wen Gong , Sven Eckelmann , stable@vger.kernel.org Subject: [PATCH] ath11k: Fix buffer overflow when scanning with extraie Date: Tue, 7 Dec 2021 15:29:13 +0100 Message-Id: <20211207142913.1734635-1-sven@narfation.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org If cfg80211 is providing extraie's for a scanning process then ath11k will copy that over to the firmware. The extraie.len is a 32 bit value in struct element_info and describes the amount of bytes for the vendor information elements. The WMI_TLV packet is having a special WMI_TAG_ARRAY_BYTE section. This section can have a (payload) length up to 65535 bytes because the WMI_TLV_LEN can store up to 16 bits. The code was missing such a check and could have created a scan request which cannot be parsed correctly by the firmware. But the bigger problem was the allocation of the buffer. It has to align the TLV sections by 4 bytes. But the code was using an u8 to store the newly calculated length of this section (with alignment). And the new calculated length was then used to allocate the skbuff. But the actual code to copy in the data is using the extraie.len and not the calculated "aligned" length. The length of extraie with IEEE80211_HW_SINGLE_SCAN_ON_ALL_BANDS enabled was 264 bytes during tests with a QCA Milan card. But it only allocated 8 bytes (264 bytes % 256) for it. As consequence, the code to memcpy the extraie into the skb was then just overwriting data after skb->end. Things like shinfo were therefore corrupted. This could usually be seen by a crash in skb_zcopy_clear which tried to call a ubuf_info callback (using a bogus address). Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-02892.1-QCAHSPSWPL_V1_V2_SILICONZ_LITE-1 Cc: stable@vger.kernel.org Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices") Signed-off-by: Sven Eckelmann --- drivers/net/wireless/ath/ath11k/wmi.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/ath/ath11k/wmi.c b/drivers/net/wireless/ath/ath11k/wmi.c index 6da16d095e37..d817ea468ab5 100644 --- a/drivers/net/wireless/ath/ath11k/wmi.c +++ b/drivers/net/wireless/ath/ath11k/wmi.c @@ -2115,7 +2115,7 @@ int ath11k_wmi_send_scan_start_cmd(struct ath11k *ar, void *ptr; int i, ret, len; u32 *tmp_ptr; - u8 extraie_len_with_pad = 0; + u16 extraie_len_with_pad = 0; struct hint_short_ssid *s_ssid = NULL; struct hint_bssid *hint_bssid = NULL; @@ -2134,7 +2134,7 @@ int ath11k_wmi_send_scan_start_cmd(struct ath11k *ar, len += sizeof(*bssid) * params->num_bssid; len += TLV_HDR_SIZE; - if (params->extraie.len) + if (params->extraie.len && params->extraie.len <= 0xFFFF) extraie_len_with_pad = roundup(params->extraie.len, sizeof(u32)); len += extraie_len_with_pad; @@ -2241,7 +2241,7 @@ int ath11k_wmi_send_scan_start_cmd(struct ath11k *ar, FIELD_PREP(WMI_TLV_LEN, len); ptr += TLV_HDR_SIZE; - if (params->extraie.len) + if (extraie_len_with_pad) memcpy(ptr, params->extraie.ptr, params->extraie.len);