From patchwork Thu Apr 21 00:05:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paulo Alcantara X-Patchwork-Id: 12820945 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84423C433F5 for ; Thu, 21 Apr 2022 00:06:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229877AbiDUAIz (ORCPT ); Wed, 20 Apr 2022 20:08:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46404 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376861AbiDUAIx (ORCPT ); Wed, 20 Apr 2022 20:08:53 -0400 Received: from mx.cjr.nz (mx.cjr.nz [51.158.111.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE62F14015 for ; Wed, 20 Apr 2022 17:06:04 -0700 (PDT) Received: from authenticated-user (mx.cjr.nz [51.158.111.142]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pc) by mx.cjr.nz (Postfix) with ESMTPSA id 4BC3B7FC9E; Thu, 21 Apr 2022 00:06:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cjr.nz; s=dkim; t=1650499561; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=oMuqpZBMNR6OGZj24NsBu0gqrdUPpp6dE9LjNd/DE4E=; b=KYTn2WKLA/8O9Ntffus/Pyy8GwJQJgEXmXsqyjLdvVySNTiKkbldvWoxyGtQ4o13HdF/pT oMzwsaOjqay0NsfslsfEgRYZvfdaqmfbnWwDLJGXFy38zfQ6fRWdfpH+hklsBmPPo7Gfyg 45IghFxGyBuL3YKYahLz8yuwJxmD3XmJT/6hs/sDDqhs/578LbQHdn9I+9oGu8EJTvVuyV mDTM8AG+dfNkHLQJP6Iqkya2ZwE6jhcjINbJdJa4U8D2LwC/fgm5DuMqKvVBY+TSEwsunD gktgENGBZ9AEfXkVoKThSClfz49gsvmINdnW0TP0l1uJqT+Be887RyRkxkdSdQ== From: Paulo Alcantara To: linux-cifs@vger.kernel.org, smfrench@gmail.com Cc: Paulo Alcantara Subject: [PATCH 1/2] cifs: fix NULL ptr dereference in refresh_mounts() Date: Wed, 20 Apr 2022 21:05:45 -0300 Message-Id: <20220421000546.5129-1-pc@cjr.nz> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Either mount(2) or automount might not have server->origin_fullpath set yet while refresh_cache_worker() is attempting to refresh DFS referrals. Add missing NULL check and locking around it. This fixes bellow crash: [ 1070.276835] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI [ 1070.277676] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] [ 1070.278219] CPU: 1 PID: 8506 Comm: kworker/u8:1 Not tainted 5.18.0-rc3 #10 [ 1070.278701] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.15.0-0-g2dd4b9b-rebuilt.opensuse.org 04/01/2014 [ 1070.279495] Workqueue: cifs-dfscache refresh_cache_worker [cifs] [ 1070.280044] RIP: 0010:strcasecmp+0x34/0x150 [ 1070.280359] Code: 00 00 00 fc ff df 41 54 55 48 89 fd 53 48 83 ec 10 eb 03 4c 89 fe 48 89 ef 48 83 c5 01 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 <42> 0f b6 04 28 38 d0 7f 08 84 c0 0f 85 bc 00 00 00 0f b6 45 ff 44 [ 1070.281729] RSP: 0018:ffffc90008367958 EFLAGS: 00010246 [ 1070.282114] RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000 [ 1070.282691] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 1070.283273] RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff873eda27 [ 1070.283857] R10: ffffc900083679a0 R11: 0000000000000001 R12: ffff88812624c000 [ 1070.284436] R13: dffffc0000000000 R14: ffff88810e6e9a88 R15: ffff888119bb9000 [ 1070.284990] FS: 0000000000000000(0000) GS:ffff888151200000(0000) knlGS:0000000000000000 [ 1070.285625] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1070.286100] CR2: 0000561a4d922418 CR3: 000000010aecc000 CR4: 0000000000350ee0 [ 1070.286683] Call Trace: [ 1070.286890] [ 1070.287070] refresh_cache_worker+0x895/0xd20 [cifs] [ 1070.287475] ? __refresh_tcon.isra.0+0xfb0/0xfb0 [cifs] [ 1070.287905] ? __lock_acquire+0xcd1/0x6960 [ 1070.288247] ? is_dynamic_key+0x1a0/0x1a0 [ 1070.288591] ? lockdep_hardirqs_on_prepare+0x410/0x410 [ 1070.289012] ? lock_downgrade+0x6f0/0x6f0 [ 1070.289318] process_one_work+0x7bd/0x12d0 [ 1070.289637] ? worker_thread+0x160/0xec0 [ 1070.289970] ? pwq_dec_nr_in_flight+0x230/0x230 [ 1070.290318] ? _raw_spin_lock_irq+0x5e/0x90 [ 1070.290619] worker_thread+0x5ac/0xec0 [ 1070.290891] ? process_one_work+0x12d0/0x12d0 [ 1070.291199] kthread+0x2a5/0x350 [ 1070.291430] ? kthread_complete_and_exit+0x20/0x20 [ 1070.291770] ret_from_fork+0x22/0x30 [ 1070.292050] [ 1070.292223] Modules linked in: bpfilter cifs cifs_arc4 cifs_md4 [ 1070.292765] ---[ end trace 0000000000000000 ]--- [ 1070.293108] RIP: 0010:strcasecmp+0x34/0x150 [ 1070.293471] Code: 00 00 00 fc ff df 41 54 55 48 89 fd 53 48 83 ec 10 eb 03 4c 89 fe 48 89 ef 48 83 c5 01 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 <42> 0f b6 04 28 38 d0 7f 08 84 c0 0f 85 bc 00 00 00 0f b6 45 ff 44 [ 1070.297718] RSP: 0018:ffffc90008367958 EFLAGS: 00010246 [ 1070.298622] RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000 [ 1070.299428] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 1070.300296] RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff873eda27 [ 1070.301204] R10: ffffc900083679a0 R11: 0000000000000001 R12: ffff88812624c000 [ 1070.301932] R13: dffffc0000000000 R14: ffff88810e6e9a88 R15: ffff888119bb9000 [ 1070.302645] FS: 0000000000000000(0000) GS:ffff888151200000(0000) knlGS:0000000000000000 [ 1070.303462] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1070.304131] CR2: 0000561a4d922418 CR3: 000000010aecc000 CR4: 0000000000350ee0 [ 1070.305004] Kernel panic - not syncing: Fatal exception [ 1070.305711] Kernel Offset: disabled [ 1070.305971] ---[ end Kernel panic - not syncing: Fatal exception ]--- Signed-off-by: Paulo Alcantara (SUSE) --- fs/cifs/connect.c | 2 ++ fs/cifs/dfs_cache.c | 19 ++++++++++++------- 2 files changed, 14 insertions(+), 7 deletions(-) diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 902e8c6c0f9c..2c24d433061a 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -3675,9 +3675,11 @@ static void setup_server_referral_paths(struct mount_ctx *mnt_ctx) { struct TCP_Server_Info *server = mnt_ctx->server; + mutex_lock(&server->refpath_lock); server->origin_fullpath = mnt_ctx->origin_fullpath; server->leaf_fullpath = mnt_ctx->leaf_fullpath; server->current_fullpath = mnt_ctx->leaf_fullpath; + mutex_unlock(&server->refpath_lock); mnt_ctx->origin_fullpath = mnt_ctx->leaf_fullpath = NULL; } diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c index 30e040da4f09..956f8e5cf3e7 100644 --- a/fs/cifs/dfs_cache.c +++ b/fs/cifs/dfs_cache.c @@ -1422,12 +1422,14 @@ static int refresh_tcon(struct cifs_ses **sessions, struct cifs_tcon *tcon, bool struct TCP_Server_Info *server = tcon->ses->server; mutex_lock(&server->refpath_lock); - if (strcasecmp(server->leaf_fullpath, server->origin_fullpath)) - __refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, force_refresh); + if (server->origin_fullpath) { + if (server->leaf_fullpath && strcasecmp(server->leaf_fullpath, + server->origin_fullpath)) + __refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, force_refresh); + __refresh_tcon(server->origin_fullpath + 1, sessions, tcon, force_refresh); + } mutex_unlock(&server->refpath_lock); - __refresh_tcon(server->origin_fullpath + 1, sessions, tcon, force_refresh); - return 0; } @@ -1530,11 +1532,14 @@ static void refresh_mounts(struct cifs_ses **sessions) list_del_init(&tcon->ulist); mutex_lock(&server->refpath_lock); - if (strcasecmp(server->leaf_fullpath, server->origin_fullpath)) - __refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, false); + if (server->origin_fullpath) { + if (server->leaf_fullpath && strcasecmp(server->leaf_fullpath, + server->origin_fullpath)) + __refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, false); + __refresh_tcon(server->origin_fullpath + 1, sessions, tcon, false); + } mutex_unlock(&server->refpath_lock); - __refresh_tcon(server->origin_fullpath + 1, sessions, tcon, false); cifs_put_tcon(tcon); } }