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 88E749460; Sat, 17 Oct 2026 17:40:51 +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=1792258852; cv=none; b=LrzbcFQXUAZEQcd/1PM1dQ4GseXZazpf8/5MpaKVtM2NvN+Gnz1iG/pK34VibVd8Qq5wXuydVYT9eIL1uN1NnjU2jHvTylcpcgQRQxyaK3A0/fkVBL6NAP+/d5NVkhkvVGlnGrWlbBu+NNa2VKAsyJKWrejQ5ldm7T5l4BP2ulE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258852; c=relaxed/simple; bh=VdpoZ5eyQ7/e2TCURPjhZiM92a35mNROWjQU2XJluSE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PMu0R4tmarwZ2H/j8bfrmDqFEUDMS/Y2tzBta1n83CC+Vo8vtFrZLx3Z+Y4USRyX0A8b+ZS56Z9fgZZ5AesD5+pKIiMGJ6hrqthQNzcWY1SAPnJlMQ6WYeLjdoKNaAM/IC032bRvU/YrDT6Gx86ivyvhlKwfvYR+YdnRuk268Fg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QpOmZQfe; 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="QpOmZQfe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9FE4A1F000C4; Sat, 17 Oct 2026 17:40:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792258851; bh=i+wgrccMdMeyOUMpPXLw6fOIbxRd7dytqMfvDXMhVU8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QpOmZQfetSLqXywgpz44/Azt/0TaEzoam1tpqPr3Hnui93qVL0s2secCYt99BRq2M NULkTf6mib89E5RgIyTSjIP8v2KL6GCMPpCwrusZwuCB3rDCcD+pLW3F0wx5TQbf0R g7LonnDbHSBJg3U9Q9xAfYPip5f2Mn167AXEjz5o= 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 6.6 0980/1674] tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR Date: Sat, 17 Oct 2026 17:54:12 +0200 Message-ID: <20261017160456.279805552@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@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 6.6-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 5f01c875e49ee..40aea069c3ad3 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