6.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Arnd Bergmann arnd@arndb.de
[ Upstream commit a7a2ef0c4b3efbd7d6f3fabd87dbbc0b3f2de5af ]
While looking at a bug, I got rather confused by the layout of the 'status' field in ieee80211_tx_info. Apparently, the intention is that status_driver_data[] is used for driver specific data, and fills up the size of the union to 40 bytes, just like the other ones.
This is indeed what actually happens, but only because of the combination of two mistakes:
- "void *status_driver_data[18 / sizeof(void *)];" is intended to be 18 bytes long but is actually two bytes shorter because of rounding-down in the division, to a multiple of the pointer size (4 bytes or 8 bytes).
- The other fields combined are intended to be 22 bytes long, but are actually 24 bytes because of padding in front of the unaligned tx_time member, and in front of the pointer array.
The two mistakes cancel out. so the size ends up fine, but it seems more helpful to make this explicit, by having a multiple of 8 bytes in the size calculation and explicitly describing the padding.
Fixes: ea5907db2a9cc ("mac80211: fix struct ieee80211_tx_info size") Fixes: 02219b3abca59 ("mac80211: add WMM admission control support") Signed-off-by: Arnd Bergmann arnd@arndb.de Reviewed-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/20230623152443.2296825-2-arnd@kernel.org Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/mac80211.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 67d81f7186660..52b336ada480c 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -1192,9 +1192,11 @@ struct ieee80211_tx_info { u8 ampdu_ack_len; u8 ampdu_len; u8 antenna; + u8 pad; u16 tx_time; u8 flags; - void *status_driver_data[18 / sizeof(void *)]; + u8 pad2; + void *status_driver_data[16 / sizeof(void *)]; } status; struct { struct ieee80211_tx_rate driver_rates[