diff options
| author | Dmitry Antipov <dmantipov@yandex.ru> | 2024-09-05 18:04:00 +0300 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2024-09-06 12:54:57 +0200 |
| commit | a26a5107bc52922cf5f67361e307ad66547b51c7 (patch) | |
| tree | 508333d55763bb0107f127a1d553d40ddeebfa49 /net/wireless | |
| parent | 43b7724487109368363bb5cda034b3f600278d14 (diff) | |
wifi: cfg80211: fix UBSAN noise in cfg80211_wext_siwscan()
Looking at https://syzkaller.appspot.com/bug?extid=1a3986bbd3169c307819
and running reproducer with CONFIG_UBSAN_BOUNDS, I've noticed the
following:
[ T4985] UBSAN: array-index-out-of-bounds in net/wireless/scan.c:3479:25
[ T4985] index 164 is out of range for type 'struct ieee80211_channel *[]'
<...skipped...>
[ T4985] Call Trace:
[ T4985] <TASK>
[ T4985] dump_stack_lvl+0x1c2/0x2a0
[ T4985] ? __pfx_dump_stack_lvl+0x10/0x10
[ T4985] ? __pfx__printk+0x10/0x10
[ T4985] __ubsan_handle_out_of_bounds+0x127/0x150
[ T4985] cfg80211_wext_siwscan+0x11a4/0x1260
<...the rest is not too useful...>
Even if we do 'creq->n_channels = n_channels' before 'creq->ssids =
(void *)&creq->channels[n_channels]', UBSAN treats the latter as
off-by-one error. Fix this by using pointer arithmetic rather than
an expression with explicit array indexing and use convenient
'struct_size()' to simplify the math here and in 'kzalloc()' above.
Fixes: 5ba63533bbf6 ("cfg80211: fix alignment problem in scan request")
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20240905150400.126386-1-dmantipov@yandex.ru
[fix coding style for multi-line calculation]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/wireless')
| -rw-r--r-- | net/wireless/scan.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 64eeed82d43d..3ff818849d83 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -3467,8 +3467,8 @@ int cfg80211_wext_siwscan(struct net_device *dev, n_channels = ieee80211_get_num_supported_channels(wiphy); } - creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) + - n_channels * sizeof(void *), + creq = kzalloc(struct_size(creq, channels, n_channels) + + sizeof(struct cfg80211_ssid), GFP_ATOMIC); if (!creq) return -ENOMEM; @@ -3476,7 +3476,7 @@ int cfg80211_wext_siwscan(struct net_device *dev, creq->wiphy = wiphy; creq->wdev = dev->ieee80211_ptr; /* SSIDs come after channels */ - creq->ssids = (void *)&creq->channels[n_channels]; + creq->ssids = (void *)creq + struct_size(creq, channels, n_channels); creq->n_channels = n_channels; creq->n_ssids = 1; creq->scan_start = jiffies; |