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 428C54E4C32; Thu, 17 Sep 2026 15:52:49 +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=1789660370; cv=none; b=sFxz78AON4zGxBt9aSD7/Z2KWF+bgjCEZ9OTkJVbzVnGkEU6hJCBHmVyTLHMmU6VCq1FcbcLRt25JX2KYMpEqxkUeVRBbfA51slmjyLEHHPmrxi6QjZiRgJhaSn14Zx3pXbRJr4pYd1i1p9oiTy1273o/eD/6FwjKl3UU4+YrrI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660370; c=relaxed/simple; bh=4pStbPlpKRnAtSMDENoCLpbsoyLragujbD1HK2z5P48=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NBMRpan5wnZWxiHTpo1mOEUQXqEbtSe66F9G9vVEbHhPtCPMT0lFoyZRWwW5TGQXs6nRtPYazlUUQC8bb+CHb5sMUsR+w1y5CoSptvGV5qeXrDcsWBucYc1AP91iSVczQ7RH7CKuf/d47Wn55C0DVPz2Xw+9SSKyE62Mz3unmxM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yA/hC5IT; 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="yA/hC5IT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 927531F000FF; Thu, 17 Sep 2026 15:52:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789660369; bh=KpiwNeB/ZWv1XFleao3r3rlF4P4PmszmWyU09fLPSBA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=yA/hC5ITPnDiQAwcGmCWcJK+dvC2Q4tb84I9F2nVR23RwKBAg3SofhAN2rf13ZvTX AMslItgO0OYvzWqVtunZcPSfOUn17V9HVUJY1UiouksIipt46kwCHAbhObsVuxe3Zv RRDTbfcKvuokxkIU9JrQON0ecyFPJPuL9xTVxKb8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vega , Ido Schimmel , Zhiling Zou , Eric Dumazet , Jakub Kicinski Subject: [PATCH 7.2 568/733] ipv6: flowlabel: cap duplicate leases per socket Date: Thu, 17 Sep 2026 16:14:36 +0100 Message-ID: <20260917151406.496583472@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@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 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhiling Zou commit 8d6cd188508513503805c156165de38e4e4a8615 upstream. ipv6_flowlabel_get() allocates an ipv6_fl_socklist entry for every successful GET. The recheck path for a compatible existing flowlabel links another lease without applying any lease admission check. Repeated GET requests for one shareable label can therefore grow a socket's lease list without bound. Reject a new unprivileged lease once the socket already holds FL_MAX_PER_SOCK leases. Check this on the shared recheck path so reuse of a globally interned label, including the fl_intern() collision path, is covered as well. New-label admission remains under the existing mem_check() policy. Use capable(CAP_NET_ADMIN) rather than ns_capable(), matching mem_check(). An unprivileged user must not bypass the cap by creating a user namespace and a netns where they have CAP_NET_ADMIN, which would still consume host memory. Check the capability only when the socket reaches the limit, so successful unprivileged GET requests below the cap do not generate a capability audit. Do the admission check before updating linger and expires so a rejected GET does not refresh the shared label, matching the existing socket-list allocation failure path. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reported-by: Vega Suggested-by: Ido Schimmel Signed-off-by: Zhiling Zou Reviewed-by: Eric Dumazet Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/83f8535972ff6e3741548476a1d50dec24c758be.1788415194.git.zhilinz@nebusec.ai Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_flowlabel.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) --- a/net/ipv6/ip6_flowlabel.c +++ b/net/ipv6/ip6_flowlabel.c @@ -461,6 +461,21 @@ done: return NULL; } +static bool fl_sock_at_lease_limit(const struct sock *sk) +{ + const struct ipv6_fl_socklist *sfl; + int count = 0; + + rcu_read_lock(); + for_each_sk_fl_rcu(sk, sfl) { + if (++count >= FL_MAX_PER_SOCK) + break; + } + rcu_read_unlock(); + + return count >= FL_MAX_PER_SOCK; +} + static int mem_check(struct sock *sk) { const int unpriv_total_limit = FL_MAX_SIZE - (FL_MAX_SIZE / 4); @@ -679,6 +694,10 @@ recheck: err = -ENOMEM; if (!sfl1) goto release; + err = -ENOBUFS; + if (fl_sock_at_lease_limit(sk) && + !capable(CAP_NET_ADMIN)) + goto release; if (fl->linger > fl1->linger) fl1->linger = fl->linger; if ((long)(fl->expires - fl1->expires) > 0)