From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB620299920; Sat, 12 Sep 2026 09:36:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789205813; cv=none; b=cjCpAgIZyhOAKjKYjDB5T8rSdbuJawqqbCSdu0mbBxjXrWn9xmRGc+ZLcWLv1VvyiMxfK1RuTunGjmPvcbxtnuHsXKFarC/9rk4Otu70E6dIxv49SUysZuO2cJ0YN7S2VJISjL7Ymiw/5WpaJ0LYsbE2wBOItLZrG2q1qL+aHwY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789205813; c=relaxed/simple; bh=zRYAOfg08Ev7Fw24Jlol5KlKcitpMrhzoGKLzANzGUM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hsLalikbDSqo6j6Y492X+XSm09jKLpbXiBK/FAfbX45oqw8qs419aYdoZb1e+eRNSaOSzgR/HBZ+ZLvsV86lXQpHcJ08p3L25KCGbNb+EJ8voEId8J26gxy3dtfT57KF8a72hAtfYUV6ds+VxMl1UNG5xh1r5iW+WyqeR11DTD8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tV7uctJq; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="tV7uctJq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 94C541F000FF; Sat, 12 Sep 2026 09:36:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789205811; bh=NI44hymHiyLoZM77Pb3hVh95vSShOijTD5TQj0CQAYk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=tV7uctJqsw8M9I689Od8E++txzkubq/B87JvtQnIoEXsCk0UK70ASJYSp0+3ukNAD xqwscvMpNdsjlwkypEvSQaabaspl5LqDwbinmXfpdWoiDVzRSdH3F7j+M36iYs2J3H hPk2D9p7ZfIcytqNbp+9dPSZt9iRbNHHVAlbKJFw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+791be35f1fbcc85d06d7@syzkaller.appspotmail.com, stable , Jeffin Philip , Alan Stern , Sasha Levin Subject: [PATCH 6.18 0077/1518] usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers() Date: Sat, 12 Sep 2026 08:37:26 +0200 Message-ID: <20260912065625.199571237@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065623.398859879@linuxfoundation.org> References: <20260912065623.398859879@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeffin Philip [ Upstream commit 2c0f5ca48674a5b5f9fa4a9c3325aa48053af0bc ] Previously fsg_num_buffers_validate() was removed as it was not necessary due to Kconfig setting the limits for n from 2 to 256 with default as 2. However, setting the page content in such a way that kstrtou8() reflects n value as either 0 or 1 bypasses these restrictions leading to a null pointer dereference if n is 0. Fix this by adding a check for n < 2 and returning -EINVAL if n is either 0 or 1 consistent with Kconfig logic. Reported-by: syzbot+791be35f1fbcc85d06d7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=791be35f1fbcc85d06d7 Fixes: fe5a6c48fd95 ("usb: gadget: storage: get rid of fsg_num_buffers_validate()") Cc: stable Signed-off-by: Jeffin Philip Acked-by: Alan Stern Link: https://patch.msgid.link/20260818035904.10324-1-jeffinphilip14@gmail.com Signed-off-by: Greg Kroah-Hartman [ adjusted context to retain the branch’s existing kcalloc() call instead of kzalloc_objs(). ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_mass_storage.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/usb/gadget/function/f_mass_storage.c +++ b/drivers/usb/gadget/function/f_mass_storage.c @@ -2748,6 +2748,9 @@ int fsg_common_set_num_buffers(struct fs struct fsg_buffhd *bh, *buffhds; int i; + if (n < 2) + return -EINVAL; + buffhds = kcalloc(n, sizeof(*buffhds), GFP_KERNEL); if (!buffhds) return -ENOMEM;