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 8136D1A00CE for ; Mon, 20 Oct 2025 16:20:39 +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=1760977240; cv=none; b=jbWVwnGAeIm4Vv4WDL5xVKe4Vb6jdB2mtrnO/H55BxO8WIwzGBA7hHbvur8d3KahUHey4WgYzaQmskTlRl/CsALcY0Zl0IiscD94+rEdgmOPDYzwdi/uN1XzWoHyMlSQS6V7rWRJQXfwOhialJG1I7mNKDRCfu3om9D9cdqW/UQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760977240; c=relaxed/simple; bh=KBVLPc5uHytZZmAXmj83lagE2kbH1eshLHrwKCRcUxM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YmXTfI6dt5NLhzTz6BNywpoZsNECbSgcsjZoM0jKI6EJyJwwC3BGffKgARgYlQrUfA6OV5A9tH7k9o7A/RYNht9tkQ5zEbds/+cpdqbTcYTMbVs+ieSEi9/mUTcsncl8LY13qng1XCuM1hDuYJ7RR9Y4362oaor4F65rQ8vMXWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=esbwYEqt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="esbwYEqt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67000C4CEFE; Mon, 20 Oct 2025 16:20:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760977239; bh=KBVLPc5uHytZZmAXmj83lagE2kbH1eshLHrwKCRcUxM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=esbwYEqtQLP+o7MquLngsVno0N9VKT3ZY0a8Z3teTMZM6o9C6QOYdw99EkutpT4Ds V6xaC/j2ktv0Mm67akc1gFMbC2/gH1dbYxTdljuUSWkyCCDiLpXutjn0BXTusr7YS4 k5k1klRcdXSp2xKfRh+lSeNSDOcb7OkHAHei2gyfTVC1MGUmHq/sfNS6alZhHgRJQv E2HUHMG3ZbPXRUbDtoew/qWf9AD3QmxxR5QRWFVFyk0Nkr3Fs73qPy88wHp8sqHnqq 9WfXDHLVkUVq7ZZqe4hfnLINM9xq4pEAdlK7puNCdyQXTHwLONKjC9r2/lX4DCu0cn 9gnk+FbFlJ39A== From: Sasha Levin To: stable@vger.kernel.org Cc: Kuen-Han Tsai , stable@kernel.org, Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 5.15.y 3/3] usb: gadget: f_ncm: Refactor bind path to use __free() Date: Mon, 20 Oct 2025 12:20:33 -0400 Message-ID: <20251020162033.1836288-3-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251020162033.1836288-1-sashal@kernel.org> References: <2025101658-ajar-suggest-f20a@gregkh> <20251020162033.1836288-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Kuen-Han Tsai [ Upstream commit 75a5b8d4ddd4eb6b16cb0b475d14ff4ae64295ef ] After an bind/unbind cycle, the ncm->notify_req is left stale. If a subsequent bind fails, the unified error label attempts to free this stale request, leading to a NULL pointer dereference when accessing ep->ops->free_request. Refactor the error handling in the bind path to use the __free() automatic cleanup mechanism. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 Call trace: usb_ep_free_request+0x2c/0xec ncm_bind+0x39c/0x3dc usb_add_function+0xcc/0x1f0 configfs_composite_bind+0x468/0x588 gadget_bind_driver+0x104/0x270 really_probe+0x190/0x374 __driver_probe_device+0xa0/0x12c driver_probe_device+0x3c/0x218 __device_attach_driver+0x14c/0x188 bus_for_each_drv+0x10c/0x168 __device_attach+0xfc/0x198 device_initial_probe+0x14/0x24 bus_probe_device+0x94/0x11c device_add+0x268/0x48c usb_add_gadget+0x198/0x28c dwc3_gadget_init+0x700/0x858 __dwc3_set_mode+0x3cc/0x664 process_scheduled_works+0x1d8/0x488 worker_thread+0x244/0x334 kthread+0x114/0x1bc ret_from_fork+0x10/0x20 Fixes: 9f6ce4240a2b ("usb: gadget: f_ncm.c added") Cc: stable@kernel.org Signed-off-by: Kuen-Han Tsai Link: https://lore.kernel.org/r/20250916-ready-v1-3-4997bf277548@google.com Signed-off-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20250916-ready-v1-3-4997bf277548@google.com Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/f_ncm.c | 78 ++++++++++++----------------- 1 file changed, 33 insertions(+), 45 deletions(-) diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c index 00995d65b54c7..4fe6a1efe0986 100644 --- a/drivers/usb/gadget/function/f_ncm.c +++ b/drivers/usb/gadget/function/f_ncm.c @@ -11,6 +11,7 @@ * Copyright (C) 2008 Nokia Corporation */ +#include #include #include #include @@ -19,6 +20,7 @@ #include #include +#include #include "u_ether.h" #include "u_ether_configfs.h" @@ -1441,18 +1443,18 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f) struct usb_ep *ep; struct f_ncm_opts *ncm_opts; + struct usb_os_desc_table *os_desc_table __free(kfree) = NULL; + struct usb_request *request __free(free_usb_request) = NULL; + if (!can_support_ecm(cdev->gadget)) return -EINVAL; ncm_opts = container_of(f->fi, struct f_ncm_opts, func_inst); if (cdev->use_os_string) { - f->os_desc_table = kzalloc(sizeof(*f->os_desc_table), - GFP_KERNEL); - if (!f->os_desc_table) + os_desc_table = kzalloc(sizeof(*os_desc_table), GFP_KERNEL); + if (!os_desc_table) return -ENOMEM; - f->os_desc_n = 1; - f->os_desc_table[0].os_desc = &ncm_opts->ncm_os_desc; } mutex_lock(&ncm_opts->lock); @@ -1462,16 +1464,15 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f) mutex_unlock(&ncm_opts->lock); if (status) - goto fail; + return status; ncm_opts->bound = true; us = usb_gstrings_attach(cdev, ncm_strings, ARRAY_SIZE(ncm_string_defs)); - if (IS_ERR(us)) { - status = PTR_ERR(us); - goto fail; - } + if (IS_ERR(us)) + return PTR_ERR(us); + ncm_control_intf.iInterface = us[STRING_CTRL_IDX].id; ncm_data_nop_intf.iInterface = us[STRING_DATA_IDX].id; ncm_data_intf.iInterface = us[STRING_DATA_IDX].id; @@ -1481,55 +1482,47 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f) /* allocate instance-specific interface IDs */ status = usb_interface_id(c, f); if (status < 0) - goto fail; + return status; ncm->ctrl_id = status; ncm_iad_desc.bFirstInterface = status; ncm_control_intf.bInterfaceNumber = status; ncm_union_desc.bMasterInterface0 = status; - if (cdev->use_os_string) - f->os_desc_table[0].if_id = - ncm_iad_desc.bFirstInterface; - status = usb_interface_id(c, f); if (status < 0) - goto fail; + return status; ncm->data_id = status; ncm_data_nop_intf.bInterfaceNumber = status; ncm_data_intf.bInterfaceNumber = status; ncm_union_desc.bSlaveInterface0 = status; - status = -ENODEV; - /* allocate instance-specific endpoints */ ep = usb_ep_autoconfig(cdev->gadget, &fs_ncm_in_desc); if (!ep) - goto fail; + return -ENODEV; ncm->port.in_ep = ep; ep = usb_ep_autoconfig(cdev->gadget, &fs_ncm_out_desc); if (!ep) - goto fail; + return -ENODEV; ncm->port.out_ep = ep; ep = usb_ep_autoconfig(cdev->gadget, &fs_ncm_notify_desc); if (!ep) - goto fail; + return -ENODEV; ncm->notify = ep; - status = -ENOMEM; - /* allocate notification request and buffer */ - ncm->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL); - if (!ncm->notify_req) - goto fail; - ncm->notify_req->buf = kmalloc(NCM_STATUS_BYTECOUNT, GFP_KERNEL); - if (!ncm->notify_req->buf) - goto fail; - ncm->notify_req->context = ncm; - ncm->notify_req->complete = ncm_notify_complete; + request = usb_ep_alloc_request(ep, GFP_KERNEL); + if (!request) + return -ENOMEM; + request->buf = kmalloc(NCM_STATUS_BYTECOUNT, GFP_KERNEL); + if (!request->buf) + return -ENOMEM; + request->context = ncm; + request->complete = ncm_notify_complete; /* * support all relevant hardware speeds... we expect that when @@ -1549,7 +1542,7 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f) status = usb_assign_descriptors(f, ncm_fs_function, ncm_hs_function, ncm_ss_function, ncm_ss_function); if (status) - goto fail; + return status; /* * NOTE: all that is done without knowing or caring about @@ -1563,25 +1556,20 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f) hrtimer_init(&ncm->task_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT); ncm->task_timer.function = ncm_tx_timeout; + if (cdev->use_os_string) { + os_desc_table[0].os_desc = &ncm_opts->ncm_os_desc; + os_desc_table[0].if_id = ncm_iad_desc.bFirstInterface; + f->os_desc_table = no_free_ptr(os_desc_table); + f->os_desc_n = 1; + } + ncm->notify_req = no_free_ptr(request); + DBG(cdev, "CDC Network: %s speed IN/%s OUT/%s NOTIFY/%s\n", gadget_is_superspeed(c->cdev->gadget) ? "super" : gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full", ncm->port.in_ep->name, ncm->port.out_ep->name, ncm->notify->name); return 0; - -fail: - kfree(f->os_desc_table); - f->os_desc_n = 0; - - if (ncm->notify_req) { - kfree(ncm->notify_req->buf); - usb_ep_free_request(ncm->notify, ncm->notify_req); - } - - ERROR(cdev, "%s: can't bind, err %d\n", f->name, status); - - return status; } static inline struct f_ncm_opts *to_f_ncm_opts(struct config_item *item) -- 2.51.0