Linux wireless drivers development
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From: Dan Carpenter <error27@gmail.com>
To: b43-dev@lists.infradead.org
Cc: "David S. Miller" <davem@davemloft.net>, linux-wireless@vger.kernel.org
Subject: [PATCH 2/3] wifi: b43legacy: debugfs: NUL terminate string in debugfs
Date: Thu, 1 Oct 2026 10:37:46 +0300	[thread overview]
Message-ID: <909ea7a88658b5e7c183bf0fda31687a91d73818.1790839793.git.error27@gmail.com> (raw)
In-Reply-To: <cover.1790839793.git.error27@gmail.com>

The "buf" buffer is PAGE_SIZE and allocated with kzalloc().  We store a
string from the user in it and then pass it to sscanf() in the write
functions such as tsf_write_file().  The buffer is only used to store a
number so we never come close to filling up the whole PAGE_SIZE.  Reserve
the last character of the page for a NUL terminator.

This is debugfs so it's root only.

Fixes: 75388acd0cd8 ("[B43LEGACY]: add mac80211-based driver for legacy BCM43xx devices")
Signed-off-by: Dan Carpenter <error27@gmail.com>
---
 drivers/net/wireless/broadcom/b43legacy/debugfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/broadcom/b43legacy/debugfs.c b/drivers/net/wireless/broadcom/b43legacy/debugfs.c
index a04d90d7307c..7ce8bcf12f0a 100644
--- a/drivers/net/wireless/broadcom/b43legacy/debugfs.c
+++ b/drivers/net/wireless/broadcom/b43legacy/debugfs.c
@@ -259,7 +259,7 @@ static ssize_t b43legacy_debugfs_write(struct file *file,
 
 	if (!count)
 		return 0;
-	if (count > PAGE_SIZE)
+	if (count >= PAGE_SIZE)
 		return -E2BIG;
 	dev = file->private_data;
 	if (!dev)
-- 
2.53.0


  parent reply	other threads:[~2026-10-01  7:37 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-01  7:37 [PATCH 0/3] wifi: NULL terminate some user strings Dan Carpenter
2026-10-01  7:37 ` [PATCH 1/3] wifi: b43: don't pass unterminated string to sscanf() Dan Carpenter
2026-10-01  7:37 ` Dan Carpenter [this message]
2026-10-01  7:37 ` [PATCH 3/3] wifi: carl9170: NUL terminate string in debugfs Dan Carpenter
2026-10-01 17:58   ` Christian Lamparter
2026-10-01 18:31     ` Dan Carpenter
2026-10-03 22:49   ` Jeff Johnson

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