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 7145C22CBF4; Mon, 2 Jun 2025 15:00:34 +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=1748876434; cv=none; b=VQSzsM7L/jUz2gEg9mkbAwdOVtjwUVJUTxouOTWE/h6STYm5Kt/6rpxEm4sBTVjcYo+PaGigKTaX3XVkGwWootlsTG9HixjRoKJoHlMbNMeY+iP0/BF+7Va4T+bONeqPvniXjdYIdIGg1836hufOQe2r750QjSrNHJXDlONfMpY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748876434; c=relaxed/simple; bh=CbZcLwNcwag9vc/TPpugaS0l2ec9Il3oz9yLOvs7qiA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=guDLp7je9BKVcWKF4F2a2n36gqA047kJeq/rsM1ZaQN05uUoaJV8OL1tWd6Sy1bqTZ+PPC9F2cTgNnj1HdTIRJsTGSU4a5Bo8Y5U3/DnU+41RYOwB9DqcRRZw5GrcwDsO0T+SSQ4cV/uff7oaLgkCnMqIybrsA+u4WGCzpXGTNM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wy5lR+XA; 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="wy5lR+XA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CEA06C4CEEB; Mon, 2 Jun 2025 15:00:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748876434; bh=CbZcLwNcwag9vc/TPpugaS0l2ec9Il3oz9yLOvs7qiA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wy5lR+XAIedcO2tgHVLaMpAjlJcih3aVcyjEUiXj8oq1Mww9GCZXZpwipNXXYPiA2 gcVBuLPDutHtmPqmtqoDhjBQGtCs4HfHavopgkf6aFIvfB310siXhg3gmT1Hxloz7c PlSW56J94KEsMGmfj4aeO2di6cLpyEyerk+mjiiM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Anderson Nascimento , Oliver Hartkopp , Marc Kleine-Budde Subject: [PATCH 5.15 173/207] can: bcm: add missing rcu read protection for procfs content Date: Mon, 2 Jun 2025 15:49:05 +0200 Message-ID: <20250602134305.523616889@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250602134258.769974467@linuxfoundation.org> References: <20250602134258.769974467@linuxfoundation.org> User-Agent: quilt/0.68 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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Hartkopp commit dac5e6249159ac255dad9781793dbe5908ac9ddb upstream. When the procfs content is generated for a bcm_op which is in the process to be removed the procfs output might show unreliable data (UAF). As the removal of bcm_op's is already implemented with rcu handling this patch adds the missing rcu_read_lock() and makes sure the list entries are properly removed under rcu protection. Fixes: f1b4e32aca08 ("can: bcm: use call_rcu() instead of costly synchronize_rcu()") Reported-by: Anderson Nascimento Suggested-by: Anderson Nascimento Tested-by: Anderson Nascimento Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20250519125027.11900-2-socketcan@hartkopp.net Cc: stable@vger.kernel.org # >= 5.4 Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- net/can/bcm.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -207,7 +207,9 @@ static int bcm_proc_show(struct seq_file seq_printf(m, " / bound %s", bcm_proc_getifname(net, ifname, bo->ifindex)); seq_printf(m, " <<<\n"); - list_for_each_entry(op, &bo->rx_ops, list) { + rcu_read_lock(); + + list_for_each_entry_rcu(op, &bo->rx_ops, list) { unsigned long reduction; @@ -263,6 +265,9 @@ static int bcm_proc_show(struct seq_file seq_printf(m, "# sent %ld\n", op->frames_abs); } seq_putc(m, '\n'); + + rcu_read_unlock(); + return 0; } #endif /* CONFIG_PROC_FS */ @@ -811,7 +816,7 @@ static int bcm_delete_rx_op(struct list_ REGMASK(op->can_id), bcm_rx_handler, op); - list_del(&op->list); + list_del_rcu(&op->list); bcm_remove_op(op); return 1; /* done */ } @@ -831,7 +836,7 @@ static int bcm_delete_tx_op(struct list_ list_for_each_entry_safe(op, n, ops, list) { if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) && (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) { - list_del(&op->list); + list_del_rcu(&op->list); bcm_remove_op(op); return 1; /* done */ } @@ -1253,7 +1258,7 @@ static int bcm_rx_setup(struct bcm_msg_h bcm_rx_handler, op, "bcm", sk); if (err) { /* this bcm rx op is broken -> remove it */ - list_del(&op->list); + list_del_rcu(&op->list); bcm_remove_op(op); return err; }