From: Xiubo Li <xiubli@redhat.com>
To: "Jeff Layton" <jlayton@kernel.org>,
"Luís Henriques" <lhenriques@suse.de>,
"Ilya Dryomov" <idryomov@gmail.com>
Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] ceph: fix use-after-free in ceph_readdir
Date: Sat, 5 Mar 2022 20:43:04 +0800 [thread overview]
Message-ID: <79cd6979-cb02-c0a3-a4e9-d66f65d78976@redhat.com> (raw)
In-Reply-To: <55c6363a0ef0dcca3e6a7c882783f5d47dbbbdc7.camel@kernel.org>
On 3/5/22 2:20 AM, Jeff Layton wrote:
> On Fri, 2022-03-04 at 16:14 +0000, Luís Henriques wrote:
>> After calling ceph_mdsc_put_request() on dfi->last_readdir, this field
>> should be set to NULL, otherwise we may end-up freeing it twince and get
>> the following splat:
>>
>> refcount_t: underflow; use-after-free.
>> WARNING: CPU: 0 PID: 229 at lib/refcount.c:28 refcount_warn_saturate+0xa6/0xf0
>> ...
>> Call Trace:
>> <TASK>
>> ceph_readdir+0xd35/0x1460 [ceph]
>> ? _raw_spin_unlock+0x12/0x30
>> ? preempt_count_add+0x73/0xa0
>> ? _raw_spin_unlock+0x12/0x30
>> ? __mark_inode_dirty+0x27c/0x3a0
>> iterate_dir+0x7d/0x190
>> __x64_sys_getdents64+0x80/0x120
>> ? compat_fillonedir+0x160/0x160
>> do_syscall_64+0x43/0x90
>> entry_SYSCALL_64_after_hwframe+0x44/0xae
>>
>> Signed-off-by: Luís Henriques <lhenriques@suse.de>
>> ---
>> fs/ceph/dir.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
>> index 0bcb677d2199..934402f5e9e6 100644
>> --- a/fs/ceph/dir.c
>> +++ b/fs/ceph/dir.c
>> @@ -555,6 +555,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
>> le32_to_cpu(rde->inode.in->mode) >> 12)) {
>> dout("filldir stopping us...\n");
>> ceph_mdsc_put_request(dfi->last_readdir);
>> + dfi->last_readdir = NULL;
>> err = 0;
>> goto out;
>> }
> I think Xiubo fixed this in the testing branch late yesterday. It should
> no longer be needed.
Right and I have sent a new version of my previous patch to remove the
buggy code.
- Xiubo
> Thanks,
next prev parent reply other threads:[~2022-03-05 12:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-04 16:14 [PATCH 0/3] ceph: minor fixes and encrypted snapshot names Luís Henriques
2022-03-04 16:14 ` [PATCH 1/3] ceph: fix error path in ceph_readdir() Luís Henriques
2022-03-04 18:17 ` Jeff Layton
2022-03-05 14:30 ` Luís Henriques
2022-03-04 16:14 ` [PATCH 2/3] ceph: fix use-after-free in ceph_readdir Luís Henriques
2022-03-04 18:20 ` Jeff Layton
2022-03-05 12:43 ` Xiubo Li [this message]
2022-03-05 14:32 ` Luís Henriques
2022-03-04 16:14 ` [PATCH 3/3] ceph: add support for encrypted snapshot names Luís Henriques
2022-03-04 18:25 ` Jeff Layton
2022-03-05 14:34 ` Luís Henriques
2022-03-05 12:43 ` Xiubo Li
2022-03-04 16:26 ` [PATCH 0/3] ceph: minor fixes and " Luís Henriques
2022-03-04 18:30 ` Jeff Layton
2022-03-05 14:56 ` Luís Henriques
2022-03-07 0:49 ` Xiubo Li
2022-03-07 14:20 ` Luís Henriques
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