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 A8C04598C01; Thu, 17 Sep 2026 15:57:21 +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=1789660642; cv=none; b=qwUTlMsvZ5izu4vmfvSigRT7FckJxuvKTLabnEiAi4Is6B24YBGb8MNDuv1fl9n67Yuv4irwhMF4nbsuQkip1mN+SSNqZmStBG2OV+qsZa5B3vUkssv7525LdfATU+83nFVWhZP4/0hcw6n1R7XuEDgmK1PMU4Vu85jwTmBUgcI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660642; c=relaxed/simple; bh=+BJLRxosKHhGjjxZrMLkkJpaT1/FKIJcz9Mtg4ArmWU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ohA/0y39hI1LAJz9HKsy7+sszWg1s8vRLe+K2PdepWXdSdb7BojM9LVeTfpijUuB9mdcANa3UBbljiWlZDn194ZIPWvm1GFMWIcvb18LJdEdjyn/XLaAth9JsFOo0dVrjaJ4T8Clp9xCKA3EPvtuKEOiLKKY3CiGo/DDs+famrg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HtcvQ7ii; 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="HtcvQ7ii" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0CCC31F00898; Thu, 17 Sep 2026 15:57:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789660641; bh=/8F/bxHKEd2ZjIPKqi2CUFTPKam7RZrZzVgeD3flrPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HtcvQ7iipprOPNqU0taQlzML+O422wwVqTDurseI3y3okh9gCk5ENULqLVNjmpOvE nKsEXHQK3fbLJmGSHYGMg37elEsgMlRg1XDth3Cd6vNTxImxl77pNYciBP9Ao+wq8R 4M0f8yLGr+151d8RM7Nx0fVIZrLq0U4j8OIvaA+E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qing Luo , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 7.2 623/733] mptcp: pm: userspace: fix address ID overflow Date: Thu, 17 Sep 2026 16:15:31 +0100 Message-ID: <20260917151408.063046614@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: Qing Luo commit f9f0068e8813d8c10d016b030fc3a320d0b6767c upstream. When all MPTCP address IDs (1-255) are exhausted in the userspace PM, find_next_zero_bit() returns MPTCP_PM_MAX_ADDR_ID + 1 (256). This value overflows when stored in the u8 field e->addr.id, resulting in ID 0 being stored and the entry being incorrectly added to the list. ID 0 is reserved for the initial connection in MPTCP, so this overflow can cause address conflicts. Note: the in-kernel PM already has an 'endpoints == MPTCP_PM_MAX_ADDR_ID' check in mptcp_pm_nl_append_new_local_addr() that returns -ERANGE before reaching find_next_zero_bit(), preventing this overflow. So this fix only addresses the userspace PM path. Check the find_next_zero_bit() result against MPTCP_PM_MAX_ADDR_ID and return -ENOSPC if all IDs are truly exhausted. Move the ID allocation check before the memory allocation so that the error path does not need to free the allocated entry. Fixes: 4638de5aefe5 ("mptcp: handle local addrs announced by userspace PMs") Cc: stable@vger.kernel.org Signed-off-by: Qing Luo Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-8-df1de70348b6@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/pm_userspace.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) --- a/net/mptcp/pm_userspace.c +++ b/net/mptcp/pm_userspace.c @@ -69,6 +69,19 @@ static int mptcp_userspace_pm_append_new } if (!addr_match && !id_match) { + unsigned int id; + + if (!entry->addr.id && needs_id) { + id = find_next_zero_bit(id_bitmap, + MPTCP_PM_MAX_ADDR_ID + 1, 1); + if (id > MPTCP_PM_MAX_ADDR_ID) { + ret = -ENOSPC; + goto append_err; + } + } else { + id = entry->addr.id; + } + /* Memory for the entry is allocated from the * sock option buffer. */ @@ -78,10 +91,7 @@ static int mptcp_userspace_pm_append_new goto append_err; } - if (!e->addr.id && needs_id) - e->addr.id = find_next_zero_bit(id_bitmap, - MPTCP_PM_MAX_ADDR_ID + 1, - 1); + e->addr.id = id; list_add_tail_rcu(&e->list, &msk->pm.userspace_pm_local_addr_list); msk->pm.local_addr_used++; ret = e->addr.id;