From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-223.mta1.migadu.com [95.215.58.223]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7868240DB2E for ; Thu, 13 Aug 2026 10:41:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.223 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786617689; cv=none; b=l+LbprvixHBKifFrj88NJBOCExoEmN7ySM6gWnTHhw0aBRMLSYRu+hDKZ7jBau8WuV+hne+XLZkn1nvCyNanlzlVjAjQ43WfCK1rg5Egd2SxaxoYRCN6hrm7qN3HsiGLcMpEwt6Y0elk29w+CpSKKXWcFkO5ljMmgZLPBEnaDS0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786617689; c=relaxed/simple; bh=tODWp/ny09wbM0oAUnm1s+AbOryUQjizNkBbOSi77Zw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=bqoc1sr3fyNtly+vZWJsZaq6LJuxBWRv5IkMs/Z/gMw3j0EtBT9VccGvASOSaGBkEUuydSz3LcHRIQodD3lLP2XUOYnLP/H/myVHuisPPrN7Cl//ZbM9qK9GbEnq1MZXYQJ+SM8OqVmLi1NG7E4iZOmxDaFYGCa/HbXr/JcRCiM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=chenxiaosong.com; spf=pass smtp.mailfrom=chenxiaosong.com; dkim=pass (2048-bit key) header.d=chenxiaosong.com header.i=@chenxiaosong.com header.b=m1PxJsob; arc=none smtp.client-ip=95.215.58.223 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=chenxiaosong.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chenxiaosong.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=chenxiaosong.com header.i=@chenxiaosong.com header.b="m1PxJsob" X-Envelope-To: linux-cifs@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=tODWp/ny09wbM0oAUnm1s+AbOryUQjizNkBbOSi77Zw=; c=simple/simple; d=chenxiaosong.com; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1786617681; v=1; x=1787222481; b=m1PxJsobWDiGeYygMljOfkGlPU4zX8zh9lhE4IuzsdfFs2eqA0FlEmS+RE7TixxLvZjEjXTb s/VSYqd51LjgFFodzh2RzOAfnthap1I/umQyg56o5VIWIiCxcYDjxcPmUXl0KPZjjnw36rpZfgu 0eihASx9KjG+r4ufFX9/jhBok/WsVq6hlxFg97NlOssp7yTq4y1PNbWgKrOmpQi8OyAk2zJrd3w Eh1Q64GvWKd3HgU2lBURX64iEgoLGpcPFlTd9mO3V8j4Q46jEY3B7Ki3IOr8cdB/o5F+7pQ8if2 esO/TYLZGxAvG+Z4fO3tRf3NLoJq2LWLpUaHMbUIVD25g== X-Envelope-To: linux-cifs@vger.kernel.org Received: from workspace-fedora (116.128.244.171) by smtp.migadu.com with ESMTPS id 49769a1975749408; Thu, 13 Aug 2026 10:41:11 +0000 X-Migadu-Flow: FLOW_OUT From: ChenXiaoSong To: smfrench@gmail.com, linkinjeon@kernel.org, tom@talpey.com, senozhatsky@chromium.org, obnred@gmail.com Cc: linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, ChenXiaoSong Subject: [PATCH] smb/server: fix use-after-free in ksmbd_conn_transport_destroy() Date: Thu, 13 Aug 2026 10:40:42 +0000 Message-ID: <20260813104042.170080-1-chenxiaosong@chenxiaosong.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: ChenXiaoSong Reproducer (Link[1]): 1. Build kernel with CONFIG_KASAN=y 2. server: systemctl start ksmbd 3. client: mount -t cifs //localhost/export /mnt 4. client: umount /mnt 5. server: modprobe -r ksmbd The error message is as follows: ================================================================== BUG: KASAN: slab-use-after-free in proc_remove+0x3e/0x80 Read of size 8 at addr ffff88810654e098 by task modprobe/785 ... Call Trace: __dump_stack+0x19/0x30 dump_stack_lvl+0x49/0x60 print_address_description+0x7b/0x200 print_report+0x5b/0x70 kasan_report+0xed/0x130 __asan_report_load8_noabort+0x18/0x20 proc_remove+0x3e/0x80 ksmbd_conn_transport_destroy+0x2b/0x320 [ksmbd] cleanup_module+0x33/0xe00 [ksmbd] __se_sys_delete_module+0x276/0x400 __x64_sys_delete_module+0x5f/0x70 x64_sys_call+0x2675/0x3030 do_syscall_64+0xf0/0x3b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f5b56d2b02b ... Allocated by task 159: kasan_save_track+0x2f/0x70 kasan_save_alloc_info+0x40/0x50 __kasan_slab_alloc+0x52/0x70 kmem_cache_alloc_noprof+0x168/0x3e0 __proc_create+0x20b/0x710 proc_create_single_data+0x78/0x150 ksmbd_proc_create+0x24/0x30 [ksmbd] ksmbd_conn_transport_init+0x4f/0x80 [ksmbd] server_ctrl_handle_work+0x64/0x2c0 [ksmbd] process_scheduled_works+0x788/0xec0 worker_thread+0x894/0xc10 kthread+0x2e5/0x3c0 ret_from_fork+0x168/0x4f0 ret_from_fork_asm+0x1a/0x30 Freed by task 785: kasan_save_track+0x2f/0x70 kasan_save_free_info+0x4a/0x60 __kasan_slab_free+0x47/0x70 kmem_cache_free+0x122/0x410 pde_put+0xfd/0x160 remove_proc_subtree+0x365/0x540 proc_remove+0x6a/0x80 ksmbd_proc_cleanup+0x1f/0x60 [ksmbd] cleanup_module+0x18/0xe00 [ksmbd] __se_sys_delete_module+0x276/0x400 __x64_sys_delete_module+0x5f/0x70 x64_sys_call+0x2675/0x3030 do_syscall_64+0xf0/0x3b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e ================================================================== Reported-by: Kyenghwan Hwang Link[1]: https://lore.kernel.org/linux-cifs/8ea028f5-90f4-4d21-b1ac-a343f0f04d88@chenxiaosong.com/ Signed-off-by: ChenXiaoSong --- fs/smb/server/server.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/smb/server/server.c b/fs/smb/server/server.c index 0ccd123ba418..d619d1f22601 100644 --- a/fs/smb/server/server.c +++ b/fs/smb/server/server.c @@ -596,11 +596,16 @@ static int ksmbd_server_shutdown(void) { WRITE_ONCE(server_conf.state, SERVER_STATE_SHUTTING_DOWN); - ksmbd_proc_cleanup(); class_unregister(&ksmbd_control_class); ksmbd_workqueue_destroy(); ksmbd_ipc_release(); ksmbd_conn_transport_destroy(); + /* + * ksmbd_conn_transport_destroy() calls delete_proc_clients() and destroys + * sessions. ksmbd_session_destroy() removes each session's proc entry. + * Keep the procfs tree alive until these entries have been removed. + */ + ksmbd_proc_cleanup(); ksmbd_crypto_destroy(); ksmbd_free_global_file_table(); destroy_lease_table(NULL); -- 2.54.0