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 BA67E3126D0; Thu, 28 May 2026 19:53:00 +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=1779997981; cv=none; b=qVRIai/S7DiYeI7pw5g9FvuevnHqZuURz4/1GipOzv5ByTJoCN2EIK0dtE1fQPhPM+ZuYVamiYExEnu7LSM83ifVRTsBfwlAGvok8GehCkofGvZXIBkrTt0/Isxvl2F6vDzPaYWV9/Hn/HfMda5wWnNpEQ0gQRgxerGxU6POwsU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779997981; c=relaxed/simple; bh=EUhm6zG65TYYMLOAz1eTu2DE1K9SI0nC71588bYey7Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=avBORPKgay18636iDT5JNBrmGIFdHV8U3fo9yU4GTQr1ic4pwG6xtuWX4HsG7D7KrdYAZUEk1Q8JKdrtqA2EqjumiEaunbrqK7rsPX/GN1ecx0iKcacVUwQYUruOTNmLSEUd6lJVE9XmZuEGTEHB5InWQ5UWzEyp2ag5VV2FNA8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=coCnVppe; 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="coCnVppe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E05B51F000E9; Thu, 28 May 2026 19:52:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779997980; bh=WUI71er2/PWqiK9JltqVPPG9UCwvh1+jXf46gaQFauQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=coCnVppe5e8/8gVXmgDg0fMfnPQcq6il/bLyRtAnuOBkDRzAPSD+DqOHU5CAHuByT HVVyCPOg2MOkb5esFkAYA1OJKMEDrWq8xxjHOLggt1/H/VIYNLH49Ws1GIKd7DYOeV v98gZSDR9KYtcBWV860p5PCzfFwmdPgp1eyQqbgc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jeremy Laratro , Namjae Jeon , Steve French Subject: [PATCH 7.0 012/461] ksmbd: fix null pointer dereference in proc_show_files() Date: Thu, 28 May 2026 21:42:21 +0200 Message-ID: <20260528194647.207361766@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260528194646.819809818@linuxfoundation.org> References: <20260528194646.819809818@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 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeremy Laratro commit 904901561e61a2b559070b20c74a8c95491f30aa upstream. When a SMB2 client opens a file with a durable v2 handle and then issues SMB2 SESSION_LOGOFF, session_fd_check() clears fp->tcon = NULL on the reconnectable file pointer but leaves the fp registered in global_ft.idr until the durable scavenger fires (up to fp->durable_timeout seconds later). During that window any read of /proc/fs/ksmbd/files (mode 0400) panics the kernel because proc_show_files() walks global_ft.idr and unconditionally dereferences fp->tcon->id with no NULL guard. Reproducer requires only a successful SMB2 SESSION_SETUP and a share configured with 'durable handles = yes'. KASAN report on mainline 70390501d194: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:proc_show_files+0x118/0x740 Call Trace: proc_show_files+0x118/0x740 seq_read_iter+0x4ef/0xe10 proc_reg_read_iter+0x1b7/0x280 ... Guard the dereference. A durable-disconnected fp legitimately has no tcon; report its tree id as 0 rather than oopsing. Fixes: b38f99c1217a ("ksmbd: add procfs interface for runtime monitoring and statistics") Cc: stable@vger.kernel.org Signed-off-by: Jeremy Laratro Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/server/vfs_cache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c index 354c4d8a1cfb..913164c958b1 100644 --- a/fs/smb/server/vfs_cache.c +++ b/fs/smb/server/vfs_cache.c @@ -81,7 +81,7 @@ static int proc_show_files(struct seq_file *m, void *v) read_lock(&global_ft.lock); idr_for_each_entry(global_ft.idr, fp, id) { seq_printf(m, "%#-10x %#-10llx %#-10llx %#-10x", - fp->tcon->id, + fp->tcon ? fp->tcon->id : 0, fp->persistent_id, fp->volatile_id, atomic_read(&fp->refcount)); -- 2.54.0