6.8-stable review patch. If anyone has any objections, please let me know.
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From: Arnd Bergmann arnd@arndb.de
[ Upstream commit 066afafc10c9476ee36c47c9062527a17e763901 ]
The carl9170_tx_release() function sometimes triggers a fortified-memset warning in my randconfig builds:
In file included from include/linux/string.h:254, from drivers/net/wireless/ath/carl9170/tx.c:40: In function 'fortify_memset_chk', inlined from 'carl9170_tx_release' at drivers/net/wireless/ath/carl9170/tx.c:283:2, inlined from 'kref_put' at include/linux/kref.h:65:3, inlined from 'carl9170_tx_put_skb' at drivers/net/wireless/ath/carl9170/tx.c:342:9: include/linux/fortify-string.h:493:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning] 493 | __write_overflow_field(p_size_field, size);
Kees previously tried to avoid this by using memset_after(), but it seems this does not fully address the problem. I noticed that the memset_after() here is done on a different part of the union (status) than the original cast was from (rate_driver_data), which may confuse the compiler.
Unfortunately, the memset_after() trick does not work on driver_rates[] because that is part of an anonymous struct, and I could not get struct_group() to do this either. Using two separate memset() calls on the two members does address the warning though.
Fixes: fb5f6a0e8063b ("mac80211: Use memset_after() to clear tx status") Link: https://lore.kernel.org/lkml/20230623152443.2296825-1-arnd@kernel.org/ Signed-off-by: Arnd Bergmann arnd@arndb.de Reviewed-by: Kees Cook keescook@chromium.org Acked-by: Christian Lamparter chunkeey@gmail.com Signed-off-by: Kalle Valo quic_kvalo@quicinc.com Link: https://msgid.link/20240328135509.3755090-2-arnd@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/ath/carl9170/tx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/carl9170/tx.c b/drivers/net/wireless/ath/carl9170/tx.c index 6bb9aa2bfe654..88ef6e023f826 100644 --- a/drivers/net/wireless/ath/carl9170/tx.c +++ b/drivers/net/wireless/ath/carl9170/tx.c @@ -280,7 +280,8 @@ static void carl9170_tx_release(struct kref *ref) * carl9170_tx_fill_rateinfo() has filled the rate information * before we get to this point. */ - memset_after(&txinfo->status, 0, rates); + memset(&txinfo->pad, 0, sizeof(txinfo->pad)); + memset(&txinfo->rate_driver_data, 0, sizeof(txinfo->rate_driver_data));
if (atomic_read(&ar->tx_total_queued)) ar->tx_schedule = true;