Return-path: Received: from alexa-out.qualcomm.com ([129.46.98.28]:64767 "EHLO alexa-out.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932376AbdKATXf (ORCPT ); Wed, 1 Nov 2017 15:23:35 -0400 From: Maya Erez To: Kalle Valo Cc: Lior David , linux-wireless@vger.kernel.org, wil6210@qca.qualcomm.com, Maya Erez Subject: [PATCH v2 05/12] wil6210: fix length check in __wmi_send Date: Wed, 1 Nov 2017 21:23:15 +0200 Message-Id: <1509564202-30078-6-git-send-email-qca_merez@qca.qualcomm.com> (sfid-20171101_202340_444053_E2F5ECAC) In-Reply-To: <1509564202-30078-1-git-send-email-qca_merez@qca.qualcomm.com> References: <1509564202-30078-1-git-send-email-qca_merez@qca.qualcomm.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Lior David The current length check: sizeof(cmd) + len > r->entry_size will allow very large values of len (> U16_MAX - sizeof(cmd)) and can cause a buffer overflow. Fix the check to cover this case. In addition, ensure the mailbox entry_size is not too small, since this can also bypass the above check. Signed-off-by: Lior David Signed-off-by: Maya Erez --- drivers/net/wireless/ath/wil6210/interrupt.c | 22 +++++++++++++++++++++- drivers/net/wireless/ath/wil6210/wmi.c | 2 +- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/ath/wil6210/interrupt.c b/drivers/net/wireless/ath/wil6210/interrupt.c index 59def4f..5cf3417 100644 --- a/drivers/net/wireless/ath/wil6210/interrupt.c +++ b/drivers/net/wireless/ath/wil6210/interrupt.c @@ -358,6 +358,25 @@ static void wil_cache_mbox_regs(struct wil6210_priv *wil) wil_mbox_ring_le2cpus(&wil->mbox_ctl.tx); } +static bool wil_validate_mbox_regs(struct wil6210_priv *wil) +{ + size_t min_size = sizeof(struct wil6210_mbox_hdr) + + sizeof(struct wmi_cmd_hdr); + + if (wil->mbox_ctl.rx.entry_size < min_size) { + wil_err(wil, "rx mbox entry too small (%d)\n", + wil->mbox_ctl.rx.entry_size); + return false; + } + if (wil->mbox_ctl.tx.entry_size < min_size) { + wil_err(wil, "tx mbox entry too small (%d)\n", + wil->mbox_ctl.tx.entry_size); + return false; + } + + return true; +} + static irqreturn_t wil6210_irq_misc(int irq, void *cookie) { struct wil6210_priv *wil = cookie; @@ -393,7 +412,8 @@ static irqreturn_t wil6210_irq_misc(int irq, void *cookie) if (isr & ISR_MISC_FW_READY) { wil_dbg_irq(wil, "IRQ: FW ready\n"); wil_cache_mbox_regs(wil); - set_bit(wil_status_mbox_ready, wil->status); + if (wil_validate_mbox_regs(wil)) + set_bit(wil_status_mbox_ready, wil->status); /** * Actual FW ready indicated by the * WMI_FW_READY_EVENTID diff --git a/drivers/net/wireless/ath/wil6210/wmi.c b/drivers/net/wireless/ath/wil6210/wmi.c index 8a780f2..dbdf71d 100644 --- a/drivers/net/wireless/ath/wil6210/wmi.c +++ b/drivers/net/wireless/ath/wil6210/wmi.c @@ -448,7 +448,7 @@ static int __wmi_send(struct wil6210_priv *wil, u16 cmdid, void *buf, u16 len) uint retry; int rc = 0; - if (sizeof(cmd) + len > r->entry_size) { + if (len > r->entry_size - sizeof(cmd)) { wil_err(wil, "WMI size too large: %d bytes, max is %d\n", (int)(sizeof(cmd) + len), r->entry_size); return -ERANGE; -- 1.9.1