From: Johannes Berg <johannes.berg@xxxxxxxxx>
Instead of assuming 200 bytes are always enough for
all the IEs we add, give the length of the buffer
to the function and warn instead of overrunning.
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
net/mac80211/ieee80211_i.h | 3 ++-
net/mac80211/scan.c | 21 ++++++++++++---------
net/mac80211/util.c | 34 +++++++++++++++++++++++++++-------
3 files changed, 41 insertions(+), 17 deletions(-)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e13697d..f148cfa 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1034,6 +1034,7 @@ struct ieee80211_local {
enum ieee80211_band hw_scan_band;
int scan_channel_idx;
int scan_ies_len;
+ int hw_scan_ies_bufsize;
struct work_struct sched_scan_stopped_work;
struct ieee80211_sub_if_data __rcu *sched_scan_sdata;
@@ -1570,7 +1571,7 @@ void ieee80211_send_deauth_disassoc(struct ieee80211_sub_if_data *sdata,
const u8 *bssid, u16 stype, u16 reason,
bool send_frame, u8 *frame_buf);
int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
- const u8 *ie, size_t ie_len,
+ size_t buffer_len, const u8 *ie, size_t ie_len,
enum ieee80211_band band, u32 rate_mask,
u8 channel);
struct sk_buff *ieee80211_build_probe_req(struct ieee80211_sub_if_data *sdata,
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index ddd1a9a..d7c190b80 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -247,6 +247,7 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
local->hw_scan_req->n_channels = n_chans;
ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
+ local->hw_scan_ies_bufsize,
req->ie, req->ie_len, band,
req->rates[band], 0);
local->hw_scan_req->ie_len = ielen;
@@ -445,11 +446,13 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
if (local->ops->hw_scan) {
u8 *ies;
+ local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
+ local->scan_ies_len +
+ req->ie_len;
local->hw_scan_req = kmalloc(
sizeof(*local->hw_scan_req) +
req->n_channels * sizeof(req->channels[0]) +
- 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
- req->ie_len, GFP_KERNEL);
+ local->hw_scan_ies_bufsize, GFP_KERNEL);
if (!local->hw_scan_req)
return -ENOMEM;
@@ -928,7 +931,10 @@ int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_sched_scan_ies sched_scan_ies;
- int ret, i;
+ int ret, i, iebufsz;
+
+ iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
+ local->scan_ies_len + req->ie_len;
mutex_lock(&local->mtx);
@@ -946,10 +952,7 @@ int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
if (!local->hw.wiphy->bands[i])
continue;
- sched_scan_ies.ie[i] = kzalloc(2 + IEEE80211_MAX_SSID_LEN +
- local->scan_ies_len +
- req->ie_len,
- GFP_KERNEL);
+ sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
if (!sched_scan_ies.ie[i]) {
ret = -ENOMEM;
goto out_free;
@@ -957,8 +960,8 @@ int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
sched_scan_ies.len[i] =
ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
- req->ie, req->ie_len, i,
- (u32) -1, 0);
+ iebufsz, req->ie, req->ie_len,
+ i, (u32) -1, 0);
}
ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 62a2158..602fc44 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1114,12 +1114,12 @@ void ieee80211_send_deauth_disassoc(struct ieee80211_sub_if_data *sdata,
}
int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
- const u8 *ie, size_t ie_len,
+ size_t buffer_len, const u8 *ie, size_t ie_len,
enum ieee80211_band band, u32 rate_mask,
u8 channel)
{
struct ieee80211_supported_band *sband;
- u8 *pos;
+ u8 *pos = buffer, *end = buffer + buffer_len;
size_t offset = 0, noffset;
int supp_rates_len, i;
u8 rates[32];
@@ -1130,8 +1130,6 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
if (WARN_ON_ONCE(!sband))
return 0;
- pos = buffer;
-
num_rates = 0;
for (i = 0; i < sband->n_bitrates; i++) {
if ((BIT(i) & rate_mask) == 0)
@@ -1141,6 +1139,8 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
supp_rates_len = min_t(int, num_rates, 8);
+ if (end - pos < 2 + supp_rates_len)
+ goto out_err;
*pos++ = WLAN_EID_SUPP_RATES;
*pos++ = supp_rates_len;
memcpy(pos, rates, supp_rates_len);
@@ -1157,6 +1157,8 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
before_extrates,
ARRAY_SIZE(before_extrates),
offset);
+ if (end - pos < noffset - offset)
+ goto out_err;
memcpy(pos, ie + offset, noffset - offset);
pos += noffset - offset;
offset = noffset;
@@ -1164,6 +1166,8 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
ext_rates_len = num_rates - supp_rates_len;
if (ext_rates_len > 0) {
+ if (end - pos < 2 + ext_rates_len)
+ goto out_err;
*pos++ = WLAN_EID_EXT_SUPP_RATES;
*pos++ = ext_rates_len;
memcpy(pos, rates + supp_rates_len, ext_rates_len);
@@ -1171,6 +1175,8 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
}
if (channel && sband->band == IEEE80211_BAND_2GHZ) {
+ if (end - pos < 3)
+ goto out_err;
*pos++ = WLAN_EID_DS_PARAMS;
*pos++ = 1;
*pos++ = channel;
@@ -1189,14 +1195,19 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
noffset = ieee80211_ie_split(ie, ie_len,
before_ht, ARRAY_SIZE(before_ht),
offset);
+ if (end - pos < noffset - offset)
+ goto out_err;
memcpy(pos, ie + offset, noffset - offset);
pos += noffset - offset;
offset = noffset;
}
- if (sband->ht_cap.ht_supported)
+ if (sband->ht_cap.ht_supported) {
+ if (end - pos < 2 + sizeof(struct ieee80211_ht_cap))
+ goto out_err;
pos = ieee80211_ie_build_ht_cap(pos, &sband->ht_cap,
sband->ht_cap.cap);
+ }
/*
* If adding more here, adjust code in main.c
@@ -1206,15 +1217,23 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
/* add any remaining custom IEs */
if (ie && ie_len) {
noffset = ie_len;
+ if (end - pos < noffset - offset)
+ goto out_err;
memcpy(pos, ie + offset, noffset - offset);
pos += noffset - offset;
}
- if (sband->vht_cap.vht_supported)
+ if (sband->vht_cap.vht_supported) {
+ if (end - pos < 2 + sizeof(struct ieee80211_vht_cap))
+ goto out_err;
pos = ieee80211_ie_build_vht_cap(pos, &sband->vht_cap,
sband->vht_cap.cap);
+ }
return pos - buffer;
+ out_err:
+ WARN_ONCE(1, "not enough space for preq IEs\n");
+ return pos - buffer;
}
struct sk_buff *ieee80211_build_probe_req(struct ieee80211_sub_if_data *sdata,
@@ -1246,7 +1265,8 @@ struct sk_buff *ieee80211_build_probe_req(struct ieee80211_sub_if_data *sdata,
else
chan_no = ieee80211_frequency_to_channel(chan->center_freq);
- buf_len = ieee80211_build_preq_ies(local, buf, ie, ie_len, chan->band,
+ buf_len = ieee80211_build_preq_ies(local, buf, 200 + ie_len,
+ ie, ie_len, chan->band,
ratemask, chan_no);
skb = ieee80211_probereq_get(&local->hw, &sdata->vif,
--
1.8.0
--
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