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From: Christopher Ertl <Christopher.Ertl@microsoft.com>
To: Stephen Hemminger <stephen@networkplumber.org>,
	Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>,
	"somnath.kotur@broadcom.com" <somnath.kotur@broadcom.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [EXTERNAL] [PATCH 2/6] net/bnxt: fix potential data race
Date: Tue, 3 Mar 2020 18:13:22 +0000
Message-ID: <DB6PR83MB018304594088E58E2566EAE997E40@DB6PR83MB0183.EURPRD83.prod.outlook.com> (raw)
In-Reply-To: <20200303175938.14292-3-stephen@networkplumber.org>

Can we add the `volatile` qualifier to the `hwrm_cmd_resp_addr` member (in drivers/net/bnxt/bnxt.h) to get a stronger guarantee that the compiler won't insert TOCTOU races in the output?

Christopher Ertl | MSRC Vulnerabilities & Mitigations | Microsoft Limited | +44 7773976589 | Christopher.Ertl@microsoft.com
 
Microsoft Limited (company number 01624297) is a company registered in England and Wales whose registered office is at Microsoft Campus, Thames Valley Park, Reading. RG6 1WG

-----Original Message-----
From: Stephen Hemminger <stephen@networkplumber.org> 
Sent: Tuesday, March 3, 2020 6:00 PM
To: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>; somnath.kotur@broadcom.com
Cc: dev@dpdk.org; Stephen Hemminger <stephen@networkplumber.org>; Christopher Ertl <Christopher.Ertl@microsoft.com>
Subject: [EXTERNAL] [PATCH 2/6] net/bnxt: fix potential data race

The response from the firmware is accessed multiple times.
This is a potential TOCTOU error.

Reported-by: Christopher Ertl <Christopher.Ertl@microsoft.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/bnxt/bnxt_hwrm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bnxt/bnxt_hwrm.c b/drivers/net/bnxt/bnxt_hwrm.c index a9c9c7297cab..20e2f6a36713 100644
--- a/drivers/net/bnxt/bnxt_hwrm.c
+++ b/drivers/net/bnxt/bnxt_hwrm.c
@@ -3746,6 +3746,7 @@ int bnxt_hwrm_port_led_qcaps(struct bnxt *bp)  {
 	struct hwrm_port_led_qcaps_output *resp = bp->hwrm_cmd_resp_addr;
 	struct hwrm_port_led_qcaps_input req = {0};
+	uint8_t num_leds;
 	int rc;
 
 	if (BNXT_VF(bp))
@@ -3757,10 +3758,11 @@ int bnxt_hwrm_port_led_qcaps(struct bnxt *bp)
 
 	HWRM_CHECK_RESULT();
 
-	if (resp->num_leds > 0 && resp->num_leds < BNXT_MAX_LED) {
+	num_leds = resp->num_leds;
+	if (num_leds > 0 && num_leds < BNXT_MAX_LED) {
 		unsigned int i;
 
-		bp->num_leds = resp->num_leds;
+		bp->num_leds = num_leds;
 		memcpy(bp->leds, &resp->led0_id,
 			sizeof(bp->leds[0]) * bp->num_leds);
 		for (i = 0; i < bp->num_leds; i++) {
--
2.20.1


  reply	other threads:[~2020-03-05  9:17 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-03 17:59 [dpdk-dev] [PATCH 0/6] net/bnxt: bounds checking patches Stephen Hemminger
2020-03-03 17:59 ` [dpdk-dev] [PATCH 1/6] eal: add portable way to check for math overflow Stephen Hemminger
2020-03-03 22:28   ` Dmitry Kozlyuk
2020-03-03 17:59 ` [dpdk-dev] [PATCH 2/6] net/bnxt: fix potential data race Stephen Hemminger
2020-03-03 18:13   ` Christopher Ertl [this message]
2020-03-03 18:16     ` [dpdk-dev] [EXTERNAL] " Stephen Hemminger
2020-03-03 17:59 ` [dpdk-dev] [PATCH 3/6] net/bnxt: avoid potential out of bounds read Stephen Hemminger
2020-03-03 17:59 ` [dpdk-dev] [PATCH 4/6] net/bnxt: check for integer overflow in buffer sizing Stephen Hemminger
2020-03-03 17:59 ` [dpdk-dev] [PATCH 5/6] net/bnxt: add integer underflow check Stephen Hemminger
2020-03-03 17:59 ` [dpdk-dev] [PATCH 6/6] net/bnxt: sanitize max_l2_ctx Stephen Hemminger
2020-03-31 11:47 ` [dpdk-dev] [PATCH 0/6] net/bnxt: bounds checking patches Ferruh Yigit
2020-03-31 17:52   ` Ajit Khaparde
2020-03-31 18:04     ` Stephen Hemminger
2020-10-19 22:28       ` Thomas Monjalon

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