Return-path: Received: from mail-wr0-f176.google.com ([209.85.128.176]:36293 "EHLO mail-wr0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751616AbdFJT1P (ORCPT ); Sat, 10 Jun 2017 15:27:15 -0400 Received: by mail-wr0-f176.google.com with SMTP id v111so60980310wrc.3 for ; Sat, 10 Jun 2017 12:27:14 -0700 (PDT) Subject: Re: [PATCH v2] brcmfmac: Fix glom_skb leak in brcmf_sdiod_recv_chain To: Andy Shevchenko , "Peter S. Housel" Cc: Franky Lin , Hante Meuleman , Kalle Valo , Pieter-Paul Giesberts , Christian Daudt , Florian Fainelli , Florian Westphal , Martin Blumenstingl , "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" , "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" , "open list:NETWORKING DRIVERS" , open list References: <1496442569-11307-1-git-send-email-housel@acm.org> From: Arend van Spriel Message-ID: <801f5209-f5a0-7414-f8f4-1500178a680b@broadcom.com> (sfid-20170610_212751_591097_18FE8C73) Date: Sat, 10 Jun 2017 21:27:11 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 03-06-17 17:36, Andy Shevchenko wrote: > On Sat, Jun 3, 2017 at 1:29 AM, Peter S. Housel wrote: >> An earlier change to this function (3bdae810721b) fixed a leak in the >> case of an unsuccessful call to brcmf_sdiod_buffrw(). However, the >> glom_skb buffer, used for emulating a scattering read, is never used >> or referenced after its contents are copied into the destination >> buffers, and therefore always needs to be freed by the end of the >> function. [snip] >> + skb_queue_walk(pktq, skb) { >> + memcpy(skb->data, glom_skb->data, skb->len); >> + skb_pull(glom_skb, skb->len); >> + } >> } > >> + brcmu_pkt_buf_free_skb(glom_skb); > > Can we just add this one line instead or I'm missing something? I guess. We don't want to walk the packet queue if glom_skb is not carrying data due to brcmf_sdiod_buffrw() failure. So I would go with the patch below as brcmu_pkt_buf_free_skb() simply ignores null pointer. Regards, Arend --- diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c index 5bc2ba2..3722f23 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c @@ -705,7 +705,7 @@ int brcmf_sdiod_recv_pkt(struct brcmf_sdio_dev *sdiodev, struct sk_buff *pkt) int brcmf_sdiod_recv_chain(struct brcmf_sdio_dev *sdiodev, struct sk_buff_head *pktq, uint totlen) { - struct sk_buff *glom_skb; + struct sk_buff *glom_skb = NULL; struct sk_buff *skb; u32 addr = sdiodev->sbwad; int err = 0; @@ -726,10 +726,8 @@ int brcmf_sdiod_recv_chain(struct brcmf_sdio_dev *sdiodev, return -ENOMEM; err = brcmf_sdiod_buffrw(sdiodev, SDIO_FUNC_2, false, addr, glom_skb); - if (err) { - brcmu_pkt_buf_free_skb(glom_skb); + if (err) goto done; - } skb_queue_walk(pktq, skb) { memcpy(skb->data, glom_skb->data, skb->len); @@ -740,6 +738,7 @@ int brcmf_sdiod_recv_chain(struct brcmf_sdio_dev *sdiodev, pktq); done: + brcmu_pkt_buf_free_skb(glom_skb); return err; }