From 54a06835580bc4e15c453ee87db8c14655e900ef Mon Sep 17 00:00:00 2001 From: Denis Kenzior Date: Thu, 26 Jan 2023 09:59:56 -0600 Subject: [PATCH] wiphy: Fix buffer overflow due to off-by-one error Since channels numbers are used as indexes into the array, and given that channel numbers start at '1' instead of 0, make sure to allocate a buffer large enough to not overflow when the max channel number for a given band is accessed. src/manager.c:manager_wiphy_dump_callback() New wiphy phy1 added (1) ==22290== Invalid write of size 2 ==22290== at 0x4624B2: nl80211_parse_supported_frequencies (nl80211util.c:570) ==22290== by 0x417CA5: parse_supported_bands (wiphy.c:1636) ==22290== by 0x418594: wiphy_parse_attributes (wiphy.c:1805) ==22290== by 0x418E20: wiphy_update_from_genl (wiphy.c:1991) ==22290== by 0x464589: manager_wiphy_dump_callback (manager.c:564) ==22290== by 0x4CBDDA: process_unicast (genl.c:944) ==22290== by 0x4CC19C: received_data (genl.c:1056) ==22290== by 0x4C7140: io_callback (io.c:120) ==22290== by 0x4C5A97: l_main_iterate (main.c:476) ==22290== by 0x4C5BDC: l_main_run (main.c:523) ==22290== by 0x4C5F0F: l_main_run_with_signal (main.c:645) ==22290== by 0x40503B: main (main.c:600) ==22290== Address 0x4aa76ec is 0 bytes after a block of size 28 alloc'd ==22290== at 0x48417B5: malloc (vg_replace_malloc.c:393) ==22290== by 0x4BC4D1: l_malloc (util.c:62) ==22290== by 0x417BE4: parse_supported_bands (wiphy.c:1619) ==22290== by 0x418594: wiphy_parse_attributes (wiphy.c:1805) ==22290== by 0x418E20: wiphy_update_from_genl (wiphy.c:1991) ==22290== by 0x464589: manager_wiphy_dump_callback (manager.c:564) ==22290== by 0x4CBDDA: process_unicast (genl.c:944) ==22290== by 0x4CC19C: received_data (genl.c:1056) ==22290== by 0x4C7140: io_callback (io.c:120) ==22290== by 0x4C5A97: l_main_iterate (main.c:476) ==22290== by 0x4C5BDC: l_main_run (main.c:523) ==22290== by 0x4C5F0F: l_main_run_with_signal (main.c:645) ==22290== --- src/wiphy.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/wiphy.c b/src/wiphy.c index fcdc3ab8..2db2d2cd 100644 --- a/src/wiphy.c +++ b/src/wiphy.c @@ -1616,8 +1616,12 @@ static void parse_supported_bands(struct wiphy *wiphy, continue; band->freq = freq; + /* + * Since channels start at 1, allocate one extra in + * order to use channel indexes without arithmetic + */ band->freq_attrs = l_new(struct band_freq_attrs, - num_channels); + num_channels + 1); band->freqs_len = num_channels; /* Reset iter to beginning */