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From:   Dmitry Antipov <dmantipov@yandex.ru>
To:     =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
Cc:     Kalle Valo <kvalo@kernel.org>, linux-wireless@vger.kernel.org,
        Dmitry Antipov <dmantipov@yandex.ru>
Subject: [PATCH] wifi: ath9k: fix clang-specific fortify warnings
Date:   Tue, 29 Aug 2023 12:38:12 +0300
Message-ID: <20230829093856.234584-1-dmantipov@yandex.ru>
MIME-Version: 1.0
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When compiling with clang 16.0.6 and CONFIG_FORTIFY_SOURCE=y, I've
noticed the following (somewhat confusing due to absence of an actual
source code location):

In file included from drivers/net/wireless/ath/ath9k/debug.c:17:
In file included from ./include/linux/slab.h:16:
In file included from ./include/linux/gfp.h:7:
In file included from ./include/linux/mmzone.h:8:
In file included from ./include/linux/spinlock.h:56:
In file included from ./include/linux/preempt.h:79:
In file included from ./arch/x86/include/asm/preempt.h:9:
In file included from ./include/linux/thread_info.h:60:
In file included from ./arch/x86/include/asm/thread_info.h:53:
In file included from ./arch/x86/include/asm/cpufeature.h:5:
In file included from ./arch/x86/include/asm/processor.h:23:
In file included from ./arch/x86/include/asm/msr.h:11:
In file included from ./arch/x86/include/asm/cpumask.h:5:
In file included from ./include/linux/cpumask.h:12:
In file included from ./include/linux/bitmap.h:11:
In file included from ./include/linux/string.h:254:
./include/linux/fortify-string.h:592:4: warning: call to '__read_overflow2_field'
declared with 'warning' attribute: detected read beyond size of field (2nd
parameter); maybe use struct_group()? [-Wattribute-warning]
                        __read_overflow2_field(q_size_field, size);

In file included from drivers/net/wireless/ath/ath9k/htc_drv_debug.c:17:
In file included from drivers/net/wireless/ath/ath9k/htc.h:20:
In file included from ./include/linux/module.h:13:
In file included from ./include/linux/stat.h:19:
In file included from ./include/linux/time.h:60:
In file included from ./include/linux/time32.h:13:
In file included from ./include/linux/timex.h:67:
In file included from ./arch/x86/include/asm/timex.h:5:
In file included from ./arch/x86/include/asm/processor.h:23:
In file included from ./arch/x86/include/asm/msr.h:11:
In file included from ./arch/x86/include/asm/cpumask.h:5:
In file included from ./include/linux/cpumask.h:12:
In file included from ./include/linux/bitmap.h:11:
In file included from ./include/linux/string.h:254:
./include/linux/fortify-string.h:592:4: warning: call to '__read_overflow2_field'
declared with 'warning' attribute: detected read beyond size of field (2nd
parameter); maybe use struct_group()? [-Wattribute-warning]
                        __read_overflow2_field(q_size_field, size);

The compiler actually complains on 'ath9k_get_et_strings()' and
'ath9k_htc_get_et_strings()' due to the same reason: fortification logic
inteprets call to 'memcpy()' as an attempt to copy the whole array from
it's first member and so issues an overread warning. These warnings may
be silenced by passing an address of the whole array and not the first
member to 'memcpy()'.

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
---
 drivers/net/wireless/ath/ath9k/debug.c         | 2 +-
 drivers/net/wireless/ath/ath9k/htc_drv_debug.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/debug.c b/drivers/net/wireless/ath/ath9k/debug.c
index 9bc57c5a89bf..a0376a6787b8 100644
--- a/drivers/net/wireless/ath/ath9k/debug.c
+++ b/drivers/net/wireless/ath/ath9k/debug.c
@@ -1293,7 +1293,7 @@ void ath9k_get_et_strings(struct ieee80211_hw *hw,
 			  u32 sset, u8 *data)
 {
 	if (sset == ETH_SS_STATS)
-		memcpy(data, *ath9k_gstrings_stats,
+		memcpy(data, ath9k_gstrings_stats,
 		       sizeof(ath9k_gstrings_stats));
 }
 
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_debug.c b/drivers/net/wireless/ath/ath9k/htc_drv_debug.c
index c549ff3abcdc..278ddc713fdc 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_debug.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_debug.c
@@ -423,7 +423,7 @@ void ath9k_htc_get_et_strings(struct ieee80211_hw *hw,
 			      u32 sset, u8 *data)
 {
 	if (sset == ETH_SS_STATS)
-		memcpy(data, *ath9k_htc_gstrings_stats,
+		memcpy(data, ath9k_htc_gstrings_stats,
 		       sizeof(ath9k_htc_gstrings_stats));
 }
 
-- 
2.41.0