In the Linux kernel, the following vulnerability has been resolved:
wifi: ath5k: do not access array OOB
Vincent reports:
> The ath5k driver seems to do an array-index-out-of-bounds access as
> shown by the UBSAN kernel message:
> UBSAN: array-index-out-of-bounds in drivers/net/wireless/ath/ath5k/base.c:1741:20
> index 4 is out of range for type ‘ieee80211_tx_rate [4]’
> …
> Call Trace:
>
> dump_stack_lvl+0x5d/0x80
> ubsan_epilogue+0x5/0x2b
> __ubsan_handle_out_of_bounds.cold+0x46/0x4b
> ath5k_tasklet_tx+0x4e0/0x560 [ath5k]
> tasklet_action_common+0xb5/0x1c0
It is real. ‘ts->ts_final_idx’ can be 3 on 5212, so:
info->status.rates[ts->ts_final_idx + 1].idx = -1;
with the array defined as:
struct ieee80211_tx_rate rates[IEEE80211_TX_MAX_RATES];
while the size is:
#define IEEE80211_TX_MAX_RATES 4
is indeed bogus.
Set this ‘idx = -1’ sentinel only if the array index is less than the
array size. As mac80211 will not look at rates beyond the size
(IEEE80211_TX_MAX_RATES).
Note: The effect of the OOB write is negligible. It just overwrites the
next member of info->status, i.e. ack_signal.
