linux-kernel - [PATCH v1 1/1] bus: mhi: host: Fix up null pointer access in mhi_irq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1658311454-4707-1-git-send-email-quic_qianyu@quicinc.com>
Date:   Wed, 20 Jul 2022 18:04:14 +0800
From:   Qiang Yu <quic_qianyu@...cinc.com>
To:     <mani@...nel.org>, <quic_hemantk@...cinc.com>,
        <loic.poulain@...aro.org>
CC:     <mhi@...ts.linux.dev>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <quic_cang@...cinc.com>,
        Qiang Yu <quic_qianyu@...cinc.com>
Subject: [PATCH v1 1/1] bus: mhi: host: Fix up null pointer access in mhi_irq_handler

The irq handler for a shared IRQ ought to be prepared for running
even now it's being freed. So let's check the pointer used by
mhi_irq_handler to avoid null pointer access since it is probably
released before freeing IRQ.

Signed-off-by: Qiang Yu <quic_qianyu@...cinc.com>
---
 drivers/bus/mhi/host/main.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index f3aef77a..7959457 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -430,12 +430,20 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev)
 {
 	struct mhi_event *mhi_event = dev;
 	struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl;
-	struct mhi_event_ctxt *er_ctxt =
-		&mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index];
+	struct mhi_event_ctxt *er_ctxt;
 	struct mhi_ring *ev_ring = &mhi_event->ring;
-	dma_addr_t ptr = le64_to_cpu(er_ctxt->rp);
+	dma_addr_t ptr;
 	void *dev_rp;
 
+	if (!mhi_cntrl->mhi_ctxt) {
+		dev_err(&mhi_cntrl->mhi_dev->dev,
+			"mhi_ctxt has been freed\n");
+		return IRQ_HANDLED;
+	}
+
+	er_ctxt = &mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index];
+	ptr = le64_to_cpu(er_ctxt->rp);
+
 	if (!is_valid_ring_ptr(ev_ring, ptr)) {
 		dev_err(&mhi_cntrl->mhi_dev->dev,
 			"Event ring rp points outside of the event ring\n");
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.