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 88113374E60; Sat, 17 Oct 2026 16:20:09 +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=1792254010; cv=none; b=ZZCp5/2D3BQlk2qJkA27Iq+w8vO/omukvjt6WkcmfsiDGyAKqWAJpKIAn3sh9VJRtMHLdPCIqlT7cW5cFJBo8F0xH0SOsNOVePSrC0xAP5Ct2Nqh7cUEERDnU4j3X37tkyoYIazuTDFRI/E8YUpteQCtGb6MmxP+MRNxGVneSq8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254010; c=relaxed/simple; bh=4LuO4Ym92bE9QvnoRmoZAPZ3b8SiqTDbPQJI4XoPX4o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=okzaXAQN4SoRcFmqjd+L7biiD4wW7xL82rIDFhwFlqGkVOssld/VMVktaRgYfplRCWR6P+1G6wrwKJ8zHP5veCLmKdlzTf6KbGZTEPGwPuJFA54g+x+V16lII+2quuMNw7myNmGz6wmhd4ITv+WX7RQ8/jggutbYFegnBjA5qFw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lkYvAqSn; 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="lkYvAqSn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC9CB1F000C4; Sat, 17 Oct 2026 16:20:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792254009; bh=mfSaMEewt7RSxdkLYtbF0eatk44UxysfMzoFDfdX2qM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lkYvAqSngtupH51rINT85pnlsH0/nnw2N1HIaK6bwxpqN5GYwDJF7gZ4BENaHoGS6 lLubnGdN4wPJyFfpQyKL1rST8w8XeguSgH4H0ZLOYSghKdk41PJikFQP69nfgK8+l2 6YAWY9SBxEMemnjmqb7GG9qZlBLsWDDu/JRjtn5U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiang Mei , Weiming Shi , Willem de Bruijn , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 306/869] tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR Date: Sat, 17 Oct 2026 17:52:27 +0200 Message-ID: <20261017160044.920519782@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@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-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Weiming Shi [ Upstream commit bddc09212c24934643bd44fc794748d2bbb3b6cd ] In the SIOCGIFHWADDR path, tap_ioctl() copies 16 bytes of an uninitialised on-stack struct sockaddr_storage to userspace via ifr_hwaddr, but netif_get_mac_address() only writes sa_family and dev->addr_len (6 for Ethernet) bytes, leaving sa_data[6..13] uninitialised. Those 8 trailing bytes leak kernel stack contents; SIOCGIFHWADDR on a macvtap chardev returns kernel .text and direct-map pointers, defeating KASLR. Initialise ss at declaration. Fixes: 3b23a32a6321 ("net: fix dev_ifsioc_locked() race condition") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260520075736.3415676-3-bestswngs@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/tap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/tap.c b/drivers/net/tap.c index b3cb7d5a95850..018bc2941a967 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -1015,7 +1015,7 @@ static long tap_ioctl(struct file *file, unsigned int cmd, unsigned int __user *up = argp; unsigned short u; int __user *sp = argp; - struct sockaddr sa; + struct sockaddr sa = {}; int s; int ret; -- 2.53.0