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.e...@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 <step...@networkplumber.org>
Sent: Tuesday, March 3, 2020 6:00 PM
To: Ajit Kumar Khaparde <ajit.khapa...@broadcom.com>; somnath.ko...@broadcom.com
Cc: dev@dpdk.org; Stephen Hemminger <step...@networkplumber.org>; Christopher
Ertl <christopher.e...@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.e...@microsoft.com>
Signed-off-by: Stephen Hemminger <step...@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
