wifi: nl80211: Avoid address calculations via out of bounds array indexing

Before request->channels[] can be used, request->n_channels must be set.
Additionally, address calculations for memory after the "channels" array
need to be calculated from the allocation base ("request") rather than
via the first "out of bounds" index of "channels", otherwise run-time
bounds checking will throw a warning.

Reported-by: Nathan Chancellor <nathan@kernel.org>
Fixes: e3eac9f32e ("wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by")
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://msgid.link/20240424220057.work.819-kees@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Kees Cook 2024-04-24 15:01:01 -07:00 committed by Johannes Berg
parent 3d913719df
commit 838c7b8f1f

View File

@ -9162,6 +9162,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
struct wiphy *wiphy;
int err, tmp, n_ssids = 0, n_channels, i;
size_t ie_len, size;
size_t ssids_offset, ie_offset;
wiphy = &rdev->wiphy;
@ -9207,21 +9208,20 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
return -EINVAL;
size = struct_size(request, channels, n_channels);
ssids_offset = size;
size = size_add(size, array_size(sizeof(*request->ssids), n_ssids));
ie_offset = size;
size = size_add(size, ie_len);
request = kzalloc(size, GFP_KERNEL);
if (!request)
return -ENOMEM;
request->n_channels = n_channels;
if (n_ssids)
request->ssids = (void *)&request->channels[n_channels];
request->ssids = (void *)request + ssids_offset;
request->n_ssids = n_ssids;
if (ie_len) {
if (n_ssids)
request->ie = (void *)(request->ssids + n_ssids);
else
request->ie = (void *)(request->channels + n_channels);
}
if (ie_len)
request->ie = (void *)request + ie_offset;
i = 0;
if (scan_freqs) {