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From:   Tycho Andersen <tycho@tycho.ws>
To:     Christine Caulfield <ccaulfie@redhat.com>,
        David Teigland <teigland@redhat.com>
Cc:     cluster-devel@redhat.com, linux-kernel@vger.kernel.org,
        Tycho Andersen <tycho@tycho.ws>
Subject: [PATCH 2/3] dlm: don't allow zero length names
Date:   Fri,  2 Nov 2018 14:18:21 -0600
Message-Id: <20181102201822.12518-3-tycho@tycho.ws>
In-Reply-To: <20181102201822.12518-1-tycho@tycho.ws>
References: <20181102201822.12518-1-tycho@tycho.ws>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

kobject doesn't like zero length object names, so let's test for that.

Nov  2 19:48:14 dlm kernel: [   20.548713] ------------[ cut here ]------------
Nov  2 19:48:14 dlm kernel: [   20.548717] kobject: ((____ptrval____)): attempted to be registered with empty name!
Nov  2 19:48:14 dlm kernel: [   20.548747] WARNING: CPU: 2 PID: 1368 at lib/kobject.c:228 kobject_add_internal+0x689/0x800
Nov  2 19:48:14 dlm kernel: [   20.548750] Modules linked in: fuse
Nov  2 19:48:14 dlm kernel: [   20.548758] CPU: 2 PID: 1368 Comm: dlm Not tainted 4.19.0+ #36
Nov  2 19:48:14 dlm kernel: [   20.548762] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Nov  2 19:48:14 dlm kernel: [   20.548767] RIP: 0010:kobject_add_internal+0x689/0x800
Nov  2 19:48:14 dlm kernel: [   20.548771] Code: ff 48 89 df e8 d8 ec fd fe e9 fb f9 ff ff 48 89 df e8 fb ec fd fe e9 7b fa ff ff 4c 89 fe 48 c7 c7 00 e6 ed 82 e8 97 a8 b4 fe <0f> 0b bb ea ff ff ff e9 fb fb ff ff bb fe ff ff ff e9 f1 fb ff ff
Nov  2 19:48:14 dlm kernel: [   20.548775] RSP: 0018:ffff88011441f988 EFLAGS: 00010282
Nov  2 19:48:14 dlm kernel: [   20.548779] RAX: 0000000000000000 RBX: ffff880113d36600 RCX: ffffffff813c4a70
Nov  2 19:48:14 dlm kernel: [   20.548783] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88011612e770
Nov  2 19:48:14 dlm kernel: [   20.548786] RBP: ffff88011441faa8 R08: ffffed0022c25cef R09: ffffed0022c25cef
Nov  2 19:48:14 dlm kernel: [   20.548790] R10: 0000000000000001 R11: ffffed0022c25cee R12: 1ffff10022883f3d
Nov  2 19:48:14 dlm kernel: [   20.548793] R13: ffffffff82d005c0 R14: 0000000000000000 R15: ffff880112d78040
Nov  2 19:48:14 dlm kernel: [   20.548797] FS:  00007f441ba404c0(0000) GS:ffff880116100000(0000) knlGS:0000000000000000
Nov  2 19:48:14 dlm kernel: [   20.548801] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Nov  2 19:48:14 dlm kernel: [   20.548804] CR2: 00007f441b53ebb0 CR3: 00000001103c0000 CR4: 00000000000006e0
Nov  2 19:48:14 dlm kernel: [   20.548810] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Nov  2 19:48:14 dlm kernel: [   20.548814] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Nov  2 19:48:14 dlm kernel: [   20.548817] Call Trace:
Nov  2 19:48:14 dlm kernel: [   20.548833]  kobject_init_and_add+0xe4/0x140
Nov  2 19:48:14 dlm kernel: [   20.548840]  ? kset_create_and_add+0x150/0x150
Nov  2 19:48:14 dlm kernel: [   20.548845]  ? printk+0x97/0xbe
Nov  2 19:48:14 dlm kernel: [   20.548859]  ? _raw_spin_unlock_irqrestore+0x2d/0x50
Nov  2 19:48:14 dlm kernel: [   20.548874]  dlm_new_lockspace+0x1766/0x1df0
Nov  2 19:48:14 dlm kernel: [   20.548893]  ? dlm_put_lockspace+0x50/0x50
Nov  2 19:48:14 dlm kernel: [   20.548901]  ? wait_woken+0x260/0x260
Nov  2 19:48:14 dlm kernel: [   20.548913]  ? security_capable+0x4f/0x90
Nov  2 19:48:14 dlm kernel: [   20.548924]  device_write+0xb57/0x1bb0
Nov  2 19:48:14 dlm kernel: [   20.548935]  ? device_read+0xa60/0xa60
Nov  2 19:48:14 dlm kernel: [   20.548941]  ? __kasan_slab_free+0x12e/0x180
Nov  2 19:48:14 dlm kernel: [   20.548945]  ? kmem_cache_free+0xb9/0x2e0
Nov  2 19:48:14 dlm kernel: [   20.548949]  ? do_sys_open+0x182/0x340
Nov  2 19:48:14 dlm kernel: [   20.548954]  ? do_syscall_64+0x90/0x3e0
Nov  2 19:48:14 dlm kernel: [   20.548959]  ? entry_SYSCALL_64_after_hwframe+0x49/0xbe
Nov  2 19:48:14 dlm kernel: [   20.548967]  ? debug_show_all_locks+0x2d0/0x2d0
Nov  2 19:48:14 dlm kernel: [   20.548979]  __vfs_write+0xd3/0x5c0
Nov  2 19:48:14 dlm kernel: [   20.548984]  ? kernel_read+0x130/0x130
Nov  2 19:48:14 dlm kernel: [   20.548987]  ? find_held_lock+0x32/0x1c0
Nov  2 19:48:14 dlm kernel: [   20.548993]  ? find_held_lock+0x32/0x1c0
Nov  2 19:48:14 dlm kernel: [   20.549001]  ? quarantine_put+0x8e/0x150
Nov  2 19:48:14 dlm kernel: [   20.549009]  ? do_sys_open+0x182/0x340
Nov  2 19:48:14 dlm kernel: [   20.549015]  vfs_write+0x157/0x4a0
Nov  2 19:48:14 dlm kernel: [   20.549021]  ksys_write+0xb3/0x180
Nov  2 19:48:14 dlm kernel: [   20.549026]  ? __ia32_sys_read+0xa0/0xa0
Nov  2 19:48:14 dlm kernel: [   20.549028]  ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe
Nov  2 19:48:14 dlm kernel: [   20.549033]  ? trace_hardirqs_off_caller+0x5b/0x160
Nov  2 19:48:14 dlm kernel: [   20.549038]  ? do_syscall_64+0x13/0x3e0
Nov  2 19:48:14 dlm kernel: [   20.549044]  do_syscall_64+0x90/0x3e0
Nov  2 19:48:14 dlm kernel: [   20.549049]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
Nov  2 19:48:14 dlm kernel: [   20.549052] RIP: 0033:0x7f441b53f154
Nov  2 19:48:14 dlm kernel: [   20.549055] Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 b1 07 2e 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5
Nov  2 19:48:14 dlm kernel: [   20.549057] RSP: 002b:00007ffefadc1e88 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
Nov  2 19:48:14 dlm kernel: [   20.549061] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f441b53f154
Nov  2 19:48:14 dlm kernel: [   20.549063] RDX: 000000000000007c RSI: 00007ffefadc1f30 RDI: 0000000000000003
Nov  2 19:48:14 dlm kernel: [   20.549065] RBP: 00007ffefadc1fc0 R08: 0000000000000004 R09: 0000000000000000
Nov  2 19:48:14 dlm kernel: [   20.549067] R10: 0000000000000000 R11: 0000000000000246 R12: 000055817bf3f760
Nov  2 19:48:14 dlm kernel: [   20.549069] R13: 00007ffefadc20a0 R14: 0000000000000000 R15: 0000000000000000
Nov  2 19:48:14 dlm kernel: [   20.549082] irq event stamp: 3866
Nov  2 19:48:14 dlm kernel: [   20.549086] hardirqs last  enabled at (3865): [<ffffffff8124d00d>] console_unlock+0x55d/0xa90
Nov  2 19:48:14 dlm kernel: [   20.549089] hardirqs last disabled at (3866): [<ffffffff8100364b>] trace_hardirqs_off_thunk+0x1a/0x1c
Nov  2 19:48:14 dlm kernel: [   20.549092] softirqs last  enabled at (3838): [<ffffffff82a004a9>] __do_softirq+0x4a9/0x8fb
Nov  2 19:48:14 dlm kernel: [   20.549095] softirqs last disabled at (3761): [<ffffffff8112c9c1>] irq_exit+0x1a1/0x1d0
Nov  2 19:48:14 dlm kernel: [   20.549097] ---[ end trace 56e315ac4368655c ]---

Signed-off-by: Tycho Andersen <tycho@tycho.ws>
---
 fs/dlm/lockspace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index 5ba94be006ee..7b9d47fe7a34 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -431,7 +431,7 @@ static int new_lockspace(const char *name, const char *cluster,
 	int do_unreg = 0;
 	int namelen = strlen(name);
 
-	if (namelen > DLM_LOCKSPACE_LEN)
+	if (namelen > DLM_LOCKSPACE_LEN || namelen == 0)
 		return -EINVAL;
 
 	if (!lvblen || (lvblen % 8))
-- 
2.17.1