What the vulnerability does
01Description
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: > <TASK> > 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.
