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 016CB3644C1; Wed, 30 Sep 2026 17:43:39 +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=1790790220; cv=none; b=sngHYiQ5W8CvPPzsMzu6Ao9uIbNpLh4CTsiPpdiG36XIkxu5ZKzcDp+55mVcuGkyG4nd1rATRPo7i+sQsyUYQZV2OenjuNDES8aFQ9te8gv444Qc7LQCnw30Z7HGO6/UfkdFXhrvhZec/aTS1gs1PpmlhbyESp1n+madGfFK62Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790790220; c=relaxed/simple; bh=ZRog7GlzZp9+GWr9fZjRBAebFyOrAVsV0pH17gTdzDg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=r4ZZvjiVKZX5X/gTv5VLKSXd1txkHU9Kv8VrfNLG8EAOH/SrMPSE5lJ0F2vNd+WkY/20douNAzf/o3YlWr5729K9mPS+4ma7tY4YiXFo6Bk/TtUeudoXuNlPmMw5AAD8jkiRq86H1dJ0V8GvcRkeRzGownns7VQVyOaw3z+wfqw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=psGO1ef7; 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="psGO1ef7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 578C71F000FF; Wed, 30 Sep 2026 17:43:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790790218; bh=WTyjUTa89Grhe2wGHWj88OOHE9P/Y0xCRjowKRqlQDY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=psGO1ef73W3Jnufps18NyGwaVU7H71Z+Qz3fJuFJdvT1g3+HD+d/+UIgY+5mVJGup AjkcQMyx1nEH3TspnOaO8FROcaU7g2t+AHATUCo/Qk8uamjHYmftt6A8Jp6LaxJ96q YNwAw1QYb/r0GkROPonD2HcxmnMOlTqbmScr06TI= 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 , Sasha Levin Subject: [PATCH 6.12 752/877] ipv6: flowlabel: cap duplicate leases per socket Date: Wed, 30 Sep 2026 17:27:43 +0200 Message-ID: <20260930152430.925255336@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152414.738996857@linuxfoundation.org> References: <20260930152414.738996857@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: Zhiling Zou [ Upstream commit 8d6cd188508513503805c156165de38e4e4a8615 ] 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: Sasha Levin 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 @@ -462,6 +462,21 @@ 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); @@ -673,6 +688,10 @@ 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)