From patchwork Wed Oct 14 18:46:46 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 7397521 Return-Path: X-Original-To: patchwork-linux-rockchip@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 6F8459F1B9 for ; Wed, 14 Oct 2015 18:47:52 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 10AB920819 for ; Wed, 14 Oct 2015 18:47:51 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EEAE220818 for ; Wed, 14 Oct 2015 18:47:49 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZmR5W-000449-AQ; Wed, 14 Oct 2015 18:47:46 +0000 Received: from mail-pa0-x233.google.com ([2607:f8b0:400e:c03::233]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZmR5T-00042r-P1 for linux-rockchip@lists.infradead.org; Wed, 14 Oct 2015 18:47:44 +0000 Received: by payp3 with SMTP id p3so13711200pay.1 for ; Wed, 14 Oct 2015 11:47:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version:content-type :content-transfer-encoding; bh=2IuVDhfoNzMdWJLcAp3Loy0PQqCq84FOx65Dd5d2X48=; b=npaqXjskvyyjZILE1CixQXhl9dL+UpOyG5IdNpbjXsoYfMkxq9knAN29oy28C75jYA 6stX12Y7bEBp8FBc1Ler+ncpoXPIJX7hCGxrZ/5sdiOq3s17H40wMMBVUgkU3DN9Snnn medmfVoI8mZvYb1ALpvvtlZDZIna6Uq4sOwzM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-type:content-transfer-encoding; bh=2IuVDhfoNzMdWJLcAp3Loy0PQqCq84FOx65Dd5d2X48=; b=O6FAuwBG+C0e6jckjlG2fFOIcjr1WsiaHQUZnL1SHf/Lmz248MUhRCA/5RNTzFO/F1 gsornmLlg0qGtGnOt34Qi+s0nlKRbqDknOPRdxfQAEi6N1rnymtHsS+oR1K/TGiReYsz wVNXDDHwK2iaK2Fg9kPNEmq4tHR6yXZDrAFMoctnZlqWxzFx0eVtjkmhZJUqeQe4WPLN pj0jzcJ0EvPpsSBEcvQwAbabTxfztINrswriEAzLw6ifbcnpodoJWmGXMa9+v52tetjA lNlNHDDdq8AS6OG28ipeRgqx9BRxsoRyJVOz8dPJAtKdX3rKBsbgFLvPV1av/YT/5hY7 LVNw== X-Gm-Message-State: ALoCoQnANBzQGVi13jznpN6kwWEyqiIRjLozvWJUyV1+BtckOPxJ1azEhCZMQZQ+LeSW8QagmR0Q X-Received: by 10.66.146.4 with SMTP id sy4mr5087120pab.79.1444848441172; Wed, 14 Oct 2015 11:47:21 -0700 (PDT) Received: from tictac.mtv.corp.google.com ([172.22.65.76]) by smtp.gmail.com with ESMTPSA id de4sm10973118pbb.60.2015.10.14.11.47.19 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 14 Oct 2015 11:47:19 -0700 (PDT) From: Douglas Anderson To: John Youn , balbi@ti.com Subject: [PATCH] usb: dwc2: host: Fix use after free w/ simultaneous irqs Date: Wed, 14 Oct 2015 11:46:46 -0700 Message-Id: <1444848406-16451-1-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 2.6.0.rc2.230.g3dd15c0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151014_114743_883917_B9E36BF3 X-CRM114-Status: GOOD ( 17.60 ) X-Spam-Score: -2.7 (--) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: gregory.herrero@intel.com, =?UTF-8?q?Heiko=20St=C3=BCbner?= , johnyoun@synopsys.com, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, Douglas Anderson , linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, yousaf.kaukab@intel.com, Yunzhi Li , Julius Werner , dinguyen@opensource.altera.com Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+patchwork-linux-rockchip=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP While plugging / unplugging on a DWC2 host port with "slub_debug=FZPUA" enabled, I found a crash that was quite obviously a use after free. It appears that in some cases when we handle the various sub-cases of HCINT we may end up freeing the QTD. If there is more than one bit set in HCINT we may then end up continuing to use the QTD, which is bad. Let's be paranoid and check for this after each sub-case. We only do this if there are still further bits to process, so the overhead should be small. This should be safe since we officially have the "hsotg->lock" (it was grabbed in dwc2_handle_hcd_intr). The specific crash I found was: Unable to handle kernel paging request at virtual address 6b6b6b9f At the time of the crash, the kernel reported: (dwc2_hc_nak_intr+0x5c/0x198) (dwc2_handle_hcd_intr+0xa84/0xbf8) (_dwc2_hcd_irq+0x1c/0x20) (usb_hcd_irq+0x34/0x48) Popping into kgdb found that "*qtd" was filled with "0x6b", AKA qtd had been freed and filled with slub_debug poison. kgdb gave a little better stack crawl: 0 dwc2_hc_nak_intr (hsotg=hsotg@entry=0xec42e058, chan=chan@entry=0xec546dc0, chnum=chnum@entry=4, qtd=qtd@entry=0xec679600) at drivers/usb/dwc2/hcd_intr.c:1237 1 dwc2_hc_n_intr (chnum=4, hsotg=0xec42e058) at drivers/usb/dwc2/hcd_intr.c:2041 2 dwc2_hc_intr (hsotg=0xec42e058) at drivers/usb/dwc2/hcd_intr.c:2078 3 dwc2_handle_hcd_intr (hsotg=0xec42e058) at drivers/usb/dwc2/hcd_intr.c:2128 4 _dwc2_hcd_irq (hcd=) at drivers/usb/dwc2/hcd.c:2837 5 usb_hcd_irq (irq=, __hcd=) at drivers/usb/core/hcd.c:2353 Popping up to frame #1 (dwc2_hc_n_intr) found: (gdb) print /x hcint $12 = 0x12 AKA: #define HCINTMSK_CHHLTD (1 << 1) #define HCINTMSK_NAK (1 << 4) Further debugging found that by simulating receiving those two interrupts at the same time it was trivial to replicate the use-after-free. See for a patch and instructions. This lead to getting the following stack crawl of the actual free: 0 arch_kgdb_breakpoint () at arch/arm/include/asm/outercache.h:103 1 kgdb_breakpoint () at kernel/debug/debug_core.c:1054 2 dwc2_hcd_qtd_unlink_and_free (hsotg=, qh=, qtd=0xe4479a00) at drivers/usb/dwc2/hcd.h:488 3 dwc2_deactivate_qh (free_qtd=, qh=0xe5efa280, hsotg=0xed424618) at drivers/usb/dwc2/hcd_intr.c:671 4 dwc2_release_channel (hsotg=hsotg@entry=0xed424618, chan=chan@entry=0xed5be000, qtd=, halt_status=) at drivers/usb/dwc2/hcd_intr.c:742 5 dwc2_halt_channel (hsotg=0xed424618, chan=0xed5be000, qtd=, halt_status=) at drivers/usb/dwc2/hcd_intr.c:804 6 dwc2_complete_non_periodic_xfer (chnum=, halt_status=, qtd=, chan=, hsotg=) at drivers/usb/dwc2/hcd_intr.c:889 7 dwc2_hc_xfercomp_intr (hsotg=hsotg@entry=0xed424618, chan=chan@entry=0xed5be000, chnum=chnum@entry=6, qtd=qtd@entry=0xe4479a00) at drivers/usb/dwc2/hcd_intr.c:1065 8 dwc2_hc_chhltd_intr_dma (qtd=0xe4479a00, chnum=6, chan=0xed5be000, hsotg=0xed424618) at drivers/usb/dwc2/hcd_intr.c:1823 9 dwc2_hc_chhltd_intr (qtd=0xe4479a00, chnum=6, chan=0xed5be000, hsotg=0xed424618) at drivers/usb/dwc2/hcd_intr.c:1944 10 dwc2_hc_n_intr (chnum=6, hsotg=0xed424618) at drivers/usb/dwc2/hcd_intr.c:2052 11 dwc2_hc_intr (hsotg=0xed424618) at drivers/usb/dwc2/hcd_intr.c:2097 12 dwc2_handle_hcd_intr (hsotg=0xed424618) at drivers/usb/dwc2/hcd_intr.c:2147 13 _dwc2_hcd_irq (hcd=) at drivers/usb/dwc2/hcd.c:2837 14 usb_hcd_irq (irq=, __hcd=) at drivers/usb/core/hcd.c:2353 Though we could add specific code to handle this case, adding the general purpose code to check for all cases where qtd might be freed seemed safer. Signed-off-by: Douglas Anderson --- drivers/usb/dwc2/hcd_intr.c | 80 +++++++++++++++++++++++++++++++++++++++------ 1 file changed, 70 insertions(+), 10 deletions(-) diff --git a/drivers/usb/dwc2/hcd_intr.c b/drivers/usb/dwc2/hcd_intr.c index f70c970..57e71f9d 100644 --- a/drivers/usb/dwc2/hcd_intr.c +++ b/drivers/usb/dwc2/hcd_intr.c @@ -1949,6 +1949,25 @@ static void dwc2_hc_chhltd_intr(struct dwc2_hsotg *hsotg, } } +/* + * Check if the given qtd is still the top of the list (and thus valid). + * + * If dwc2_hcd_qtd_unlink_and_free() has been called since we grabbed + * the qtd from the top of the list, this will return NULL. Otherwise + * it will be passed back qtd. + */ +struct dwc2_qtd *dwc2_check_qtd_still_ok(struct dwc2_qtd *qtd, + struct list_head *qtd_list) +{ + struct dwc2_qtd *cur_head; + + cur_head = list_first_entry(qtd_list, struct dwc2_qtd, qtd_list_entry); + if (cur_head == qtd) + return qtd; + + return NULL; +} + /* Handles interrupt for a specific Host Channel */ static void dwc2_hc_n_intr(struct dwc2_hsotg *hsotg, int chnum) { @@ -2031,26 +2050,67 @@ static void dwc2_hc_n_intr(struct dwc2_hsotg *hsotg, int chnum) */ hcint &= ~HCINTMSK_NYET; } - if (hcint & HCINTMSK_CHHLTD) + + if (hcint & HCINTMSK_CHHLTD) { + hcint &= ~HCINTMSK_CHHLTD; dwc2_hc_chhltd_intr(hsotg, chan, chnum, qtd); - if (hcint & HCINTMSK_AHBERR) + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } + if (hcint & HCINTMSK_AHBERR) { + hcint &= ~HCINTMSK_AHBERR; dwc2_hc_ahberr_intr(hsotg, chan, chnum, qtd); - if (hcint & HCINTMSK_STALL) + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } + if (hcint & HCINTMSK_STALL) { + hcint &= ~HCINTMSK_STALL; dwc2_hc_stall_intr(hsotg, chan, chnum, qtd); - if (hcint & HCINTMSK_NAK) + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } + if (hcint & HCINTMSK_NAK) { + hcint &= ~HCINTMSK_NAK; dwc2_hc_nak_intr(hsotg, chan, chnum, qtd); - if (hcint & HCINTMSK_ACK) + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } + if (hcint & HCINTMSK_ACK) { + hcint &= ~HCINTMSK_ACK; dwc2_hc_ack_intr(hsotg, chan, chnum, qtd); - if (hcint & HCINTMSK_NYET) + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } + if (hcint & HCINTMSK_NYET) { + hcint &= ~HCINTMSK_NYET; dwc2_hc_nyet_intr(hsotg, chan, chnum, qtd); - if (hcint & HCINTMSK_XACTERR) + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } + if (hcint & HCINTMSK_XACTERR) { + hcint &= ~HCINTMSK_XACTERR; dwc2_hc_xacterr_intr(hsotg, chan, chnum, qtd); - if (hcint & HCINTMSK_BBLERR) + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } + if (hcint & HCINTMSK_BBLERR) { + hcint &= ~HCINTMSK_BBLERR; dwc2_hc_babble_intr(hsotg, chan, chnum, qtd); - if (hcint & HCINTMSK_FRMOVRUN) + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } + if (hcint & HCINTMSK_FRMOVRUN) { + hcint &= ~HCINTMSK_FRMOVRUN; dwc2_hc_frmovrun_intr(hsotg, chan, chnum, qtd); - if (hcint & HCINTMSK_DATATGLERR) + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } + if (hcint & HCINTMSK_DATATGLERR) { + hcint &= ~HCINTMSK_DATATGLERR; dwc2_hc_datatglerr_intr(hsotg, chan, chnum, qtd); + if (hcint) + qtd = dwc2_check_qtd_still_ok(qtd, &chan->qh->qtd_list); + } chan->hcint = 0; }