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 F12992E8898; Tue, 15 Jul 2025 13:51:40 +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=1752587501; cv=none; b=ulrhQ4RFUXHxsdGUg/sRdN5uGPYmLMsBAuFuO5seahz3VqYNqZ/qxx8SgXVSc/qNbS5gLCnTr9Iv67VGaAxifHuGT39grJ4YBnPPGA7eC09H1p8STycy6tLBQhBDnQe+Ul5ANEFmLliAsYxOYQxnsRFKifX/ccV7egMTuKMxtMY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752587501; c=relaxed/simple; bh=9JSxp7CfWyth6DuinStyfCr15+qyMsqCVAMwoZJBgLQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=vF2MAv8slDjVRlLhjvtjG20v8bl/aClbtYd/BmtqXoqEcYLpVOdN3QwJai3ani9oGGCusyAvts6Is4z1kuxYLeM+V45LTLc5sJFDkHsXRdZw9cflNAGxzWoqQAfwcC9TH/sqipva7jePK8cZJ+PkO2itQrOEkgnBKQwdWNr6dWw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0Kw79f3y; 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="0Kw79f3y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84C77C4CEE3; Tue, 15 Jul 2025 13:51:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1752587500; bh=9JSxp7CfWyth6DuinStyfCr15+qyMsqCVAMwoZJBgLQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0Kw79f3y36Oq8EcvgNDQnFrKZ91ZmD2+t3YStkmKFwbFqbeSzE5RMnqUa20f7mDcQ b2Vcha0Bq7K7lY6iilg2eUEsv443JPsEzpr3IZR3ubEx+RvCb9tJKeny6IfytQoRF9 X4pGPZjSLCz/NYhrKpGLh3NSusP465JxXC5AyGCk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shinichiro Kawasaki , Zhu Yanjun , Leon Romanovsky , Sasha Levin Subject: [PATCH 5.10 036/208] RDMA/iwcm: Fix use-after-free of work objects after cm_id destruction Date: Tue, 15 Jul 2025 15:12:25 +0200 Message-ID: <20250715130812.406314734@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250715130810.830580412@linuxfoundation.org> References: <20250715130810.830580412@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 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shin'ichiro Kawasaki [ Upstream commit 6883b680e703c6b2efddb4e7a8d891ce1803d06b ] The commit 59c68ac31e15 ("iw_cm: free cm_id resources on the last deref") simplified cm_id resource management by freeing cm_id once all references to the cm_id were removed. The references are removed either upon completion of iw_cm event handlers or when the application destroys the cm_id. This commit introduced the use-after-free condition where cm_id_private object could still be in use by event handler works during the destruction of cm_id. The commit aee2424246f9 ("RDMA/iwcm: Fix a use-after-free related to destroying CM IDs") addressed this use-after- free by flushing all pending works at the cm_id destruction. However, still another use-after-free possibility remained. It happens with the work objects allocated for each cm_id_priv within alloc_work_entries() during cm_id creation, and subsequently freed in dealloc_work_entries() once all references to the cm_id are removed. If the cm_id's last reference is decremented in the event handler work, the work object for the work itself gets removed, and causes the use- after-free BUG below: BUG: KASAN: slab-use-after-free in __pwq_activate_work+0x1ff/0x250 Read of size 8 at addr ffff88811f9cf800 by task kworker/u16:1/147091 CPU: 2 UID: 0 PID: 147091 Comm: kworker/u16:1 Not tainted 6.15.0-rc2+ #27 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 Workqueue: 0x0 (iw_cm_wq) Call Trace: dump_stack_lvl+0x6a/0x90 print_report+0x174/0x554 ? __virt_addr_valid+0x208/0x430 ? __pwq_activate_work+0x1ff/0x250 kasan_report+0xae/0x170 ? __pwq_activate_work+0x1ff/0x250 __pwq_activate_work+0x1ff/0x250 pwq_dec_nr_in_flight+0x8c5/0xfb0 process_one_work+0xc11/0x1460 ? __pfx_process_one_work+0x10/0x10 ? assign_work+0x16c/0x240 worker_thread+0x5ef/0xfd0 ? __pfx_worker_thread+0x10/0x10 kthread+0x3b0/0x770 ? __pfx_kthread+0x10/0x10 ? rcu_is_watching+0x11/0xb0 ? _raw_spin_unlock_irq+0x24/0x50 ? rcu_is_watching+0x11/0xb0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x30/0x70 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 Allocated by task 147416: kasan_save_stack+0x2c/0x50 kasan_save_track+0x10/0x30 __kasan_kmalloc+0xa6/0xb0 alloc_work_entries+0xa9/0x260 [iw_cm] iw_cm_connect+0x23/0x4a0 [iw_cm] rdma_connect_locked+0xbfd/0x1920 [rdma_cm] nvme_rdma_cm_handler+0x8e5/0x1b60 [nvme_rdma] cma_cm_event_handler+0xae/0x320 [rdma_cm] cma_work_handler+0x106/0x1b0 [rdma_cm] process_one_work+0x84f/0x1460 worker_thread+0x5ef/0xfd0 kthread+0x3b0/0x770 ret_from_fork+0x30/0x70 ret_from_fork_asm+0x1a/0x30 Freed by task 147091: kasan_save_stack+0x2c/0x50 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x60 __kasan_slab_free+0x4b/0x70 kfree+0x13a/0x4b0 dealloc_work_entries+0x125/0x1f0 [iw_cm] iwcm_deref_id+0x6f/0xa0 [iw_cm] cm_work_handler+0x136/0x1ba0 [iw_cm] process_one_work+0x84f/0x1460 worker_thread+0x5ef/0xfd0 kthread+0x3b0/0x770 ret_from_fork+0x30/0x70 ret_from_fork_asm+0x1a/0x30 Last potentially related work creation: kasan_save_stack+0x2c/0x50 kasan_record_aux_stack+0xa3/0xb0 __queue_work+0x2ff/0x1390 queue_work_on+0x67/0xc0 cm_event_handler+0x46a/0x820 [iw_cm] siw_cm_upcall+0x330/0x650 [siw] siw_cm_work_handler+0x6b9/0x2b20 [siw] process_one_work+0x84f/0x1460 worker_thread+0x5ef/0xfd0 kthread+0x3b0/0x770 ret_from_fork+0x30/0x70 ret_from_fork_asm+0x1a/0x30 This BUG is reproducible by repeating the blktests test case nvme/061 for the rdma transport and the siw driver. To avoid the use-after-free of cm_id_private work objects, ensure that the last reference to the cm_id is decremented not in the event handler works, but in the cm_id destruction context. For that purpose, move iwcm_deref_id() call from destroy_cm_id() to the callers of destroy_cm_id(). In iw_destroy_cm_id(), call iwcm_deref_id() after flushing the pending works. During the fix work, I noticed that iw_destroy_cm_id() is called from cm_work_handler() and process_event() context. However, the comment of iw_destroy_cm_id() notes that the function "cannot be called by the event thread". Drop the false comment. Closes: https://lore.kernel.org/linux-rdma/r5676e754sv35aq7cdsqrlnvyhiq5zktteaurl7vmfih35efko@z6lay7uypy3c/ Fixes: 59c68ac31e15 ("iw_cm: free cm_id resources on the last deref") Cc: stable@vger.kernel.org Signed-off-by: Shin'ichiro Kawasaki Link: https://patch.msgid.link/20250510101036.1756439-1-shinichiro.kawasaki@wdc.com Reviewed-by: Zhu Yanjun Signed-off-by: Leon Romanovsky Signed-off-by: Sasha Levin --- drivers/infiniband/core/iwcm.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c index 3e4941754b48d..ce41f235af253 100644 --- a/drivers/infiniband/core/iwcm.c +++ b/drivers/infiniband/core/iwcm.c @@ -367,12 +367,9 @@ EXPORT_SYMBOL(iw_cm_disconnect); /* * CM_ID <-- DESTROYING * - * Clean up all resources associated with the connection and release - * the initial reference taken by iw_create_cm_id. - * - * Returns true if and only if the last cm_id_priv reference has been dropped. + * Clean up all resources associated with the connection. */ -static bool destroy_cm_id(struct iw_cm_id *cm_id) +static void destroy_cm_id(struct iw_cm_id *cm_id) { struct iwcm_id_private *cm_id_priv; struct ib_qp *qp; @@ -441,20 +438,22 @@ static bool destroy_cm_id(struct iw_cm_id *cm_id) iwpm_remove_mapinfo(&cm_id->local_addr, &cm_id->m_local_addr); iwpm_remove_mapping(&cm_id->local_addr, RDMA_NL_IWCM); } - - return iwcm_deref_id(cm_id_priv); } /* - * This function is only called by the application thread and cannot - * be called by the event thread. The function will wait for all - * references to be released on the cm_id and then kfree the cm_id - * object. + * Destroy cm_id. If the cm_id still has other references, wait for all + * references to be released on the cm_id and then release the initial + * reference taken by iw_create_cm_id. */ void iw_destroy_cm_id(struct iw_cm_id *cm_id) { - if (!destroy_cm_id(cm_id)) + struct iwcm_id_private *cm_id_priv; + + cm_id_priv = container_of(cm_id, struct iwcm_id_private, id); + destroy_cm_id(cm_id); + if (refcount_read(&cm_id_priv->refcount) > 1) flush_workqueue(iwcm_wq); + iwcm_deref_id(cm_id_priv); } EXPORT_SYMBOL(iw_destroy_cm_id); @@ -1037,8 +1036,10 @@ static void cm_work_handler(struct work_struct *_work) if (!test_bit(IWCM_F_DROP_EVENTS, &cm_id_priv->flags)) { ret = process_event(cm_id_priv, &levent); - if (ret) - WARN_ON_ONCE(destroy_cm_id(&cm_id_priv->id)); + if (ret) { + destroy_cm_id(&cm_id_priv->id); + WARN_ON_ONCE(iwcm_deref_id(cm_id_priv)); + } } else pr_debug("dropping event %d\n", levent.event); if (iwcm_deref_id(cm_id_priv)) -- 2.39.5