From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 AE2B63AF643; Wed, 8 Apr 2026 18:30:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775673044; cv=none; b=SV+hc+psBD6ht3L5no2f9FvghyyiL1uCzm+3sqlTxcI1XW8NePGXFdOjfmit7jflbOicUsnARaKHJMNHtAFoCCaG4n68QId6gswMUeftxrlqSogIAB6+tEfrLQS5I7VhUjQcvQa5U5UBmwYvTPQjFNHBeQ3+l5tQ9j+08ZcLmmE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775673044; c=relaxed/simple; bh=SVA/HAtCvpYymztf/WQ4OvrREPi/nj6oB8NMfIZnKjg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=S31OfYieb+Yzp29FEkCZYpNv2/NQyr+qorshAsMgK419WDQ4cRwJu8F3CRYKyrXeOYBQ1AFrWqeYruWbHTrQr15BP/2EDgPzLF/UQCqhSsX045YiuatAINbdb9uP6Sw7tF4NgxJ93etgPfliJ+qzgzrKlOwFdXh86dUd/CbJSZE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IW+P1zbh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="IW+P1zbh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4452FC19421; Wed, 8 Apr 2026 18:30:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1775673044; bh=SVA/HAtCvpYymztf/WQ4OvrREPi/nj6oB8NMfIZnKjg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IW+P1zbh/vlDjRc9uFWqzv4OTE0nWvnLcdfacp4+p17cPRV+W9oeIBeFceJSZ9051 lTK3bZUUuwXMN4HRJIcoRwk9xLMFvKNkRhdqoBcLqq8WIl9CK5xNAfUukcQ6NCVOjn zI0InjaNpN7cKnTiu9Nvpvoeq0wMSXVwjl+Mq+n0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jakub Kicinski , Paolo Abeni , Sasha Levin Subject: [PATCH 6.18 047/277] ipv6: prevent possible UaF in addrconf_permanent_addr() Date: Wed, 8 Apr 2026 20:00:32 +0200 Message-ID: <20260408175935.614959676@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260408175933.836769063@linuxfoundation.org> References: <20260408175933.836769063@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Abeni [ Upstream commit fd63f185979b047fb22a0dfc6bd94d0cab6a6a70 ] The mentioned helper try to warn the user about an exceptional condition, but the message is delivered too late, accessing the ipv6 after its possible deletion. Reorder the statement to avoid the possible UaF; while at it, place the warning outside the idev->lock as it needs no protection. Reported-by: Jakub Kicinski Closes: https://sashiko.dev/#/patchset/8c8bfe2e1a324e501f0e15fef404a77443fd8caf.1774365668.git.pabeni%40redhat.com Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional") Signed-off-by: Paolo Abeni Link: https://patch.msgid.link/ef973c3a8cb4f8f1787ed469f3e5391b9fe95aa0.1774601542.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/addrconf.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 4a745566b760d..2d4c3d9c1a2a5 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -3621,12 +3621,12 @@ static void addrconf_permanent_addr(struct net *net, struct net_device *dev) if ((ifp->flags & IFA_F_PERMANENT) && fixup_permanent_addr(net, idev, ifp) < 0) { write_unlock_bh(&idev->lock); - in6_ifa_hold(ifp); - ipv6_del_addr(ifp); - write_lock_bh(&idev->lock); net_info_ratelimited("%s: Failed to add prefix route for address %pI6c; dropping\n", idev->dev->name, &ifp->addr); + in6_ifa_hold(ifp); + ipv6_del_addr(ifp); + write_lock_bh(&idev->lock); } } -- 2.53.0