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UBSan: Avoid unsigned integer overflow is throughput estimation

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wpa_scan_result_compar() would return wb->est_throughput -
wa->est_throughput in case the comparison is done based on the
throughput estimates. While the return value from this function is a
signed integer, these est_throughput values are unsigned integers and
need to be explicitly typecast to avoid an UBSan warning.

scan.c:1996:30: runtime error: unsigned integer overflow: 54000 - 135000 cannot be represented in type 'unsigned int'

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2019-02-23 12:42:20 +02:00
parent 3b6b3ae581
commit ec2e7c4cfa
1 changed files with 3 additions and 2 deletions
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5
wpa_supplicant/scan.c
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@ -1,6 +1,6 @@
/* /*
* WPA Supplicant - Scanning * WPA Supplicant - Scanning
* Copyright (c) 2003-2014, Jouni Malinen <j@w1.fi> * Copyright (c) 2003-2019, Jouni Malinen <j@w1.fi>
* *
* This software may be distributed under the terms of the BSD license. * This software may be distributed under the terms of the BSD license.
* See README for more details. * See README for more details.
@ -1993,7 +1993,8 @@ static int wpa_scan_result_compar(const void *a, const void *b)
/* if SNR is close, decide by max rate or frequency band */ /* if SNR is close, decide by max rate or frequency band */
if (snr_a && snr_b && abs(snr_b - snr_a) < 7) { if (snr_a && snr_b && abs(snr_b - snr_a) < 7) {
if (wa->est_throughput != wb->est_throughput) if (wa->est_throughput != wb->est_throughput)
return wb->est_throughput - wa->est_throughput; return (int) wb->est_throughput -
(int) wa->est_throughput;
} }
if ((snr_a && snr_b && abs(snr_b - snr_a) < 5) || if ((snr_a && snr_b && abs(snr_b - snr_a) < 5) ||
(wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) { (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {