2013-08-05 04:05:13

by Nathaniel Yazdani

Subject: [PATCH] ceph: fix null pointer dereference

When register_session() is given an out-of-range argument for mds,
ceph_mdsmap_get_addr() will return a null pointer, which would be given to
ceph_con_open() & be dereferenced, causing a kernel oops. This fixes bug #4685
in the Ceph bug tracker <http://tracker.ceph.com/issues/4685>.

Signed-off-by: Nathaniel Yazdani <[email protected]>
---
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 187bf21..ddff072 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -414,6 +414,9 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
{
struct ceph_mds_session *s;

+ if (mds >= mdsc->mdsmap->m_max_mds)
+ return ERR_PTR(-EINVAL);
+
s = kzalloc(sizeof(*s), GFP_NOFS);
if (!s)
return ERR_PTR(-ENOMEM);

2013-08-05 04:14:12

by Sage Weil

Subject: Re: [PATCH] ceph: fix null pointer dereference

Looks right, applied to the testing branch.

Thanks!
sage


On Sun, 4 Aug 2013, Nathaniel Yazdani wrote:

> When register_session() is given an out-of-range argument for mds,
> ceph_mdsmap_get_addr() will return a null pointer, which would be given to
> ceph_con_open() & be dereferenced, causing a kernel oops. This fixes bug #4685
> in the Ceph bug tracker <http://tracker.ceph.com/issues/4685>.
>
> Signed-off-by: Nathaniel Yazdani <[email protected]>
> ---
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 187bf21..ddff072 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -414,6 +414,9 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
> {
> struct ceph_mds_session *s;
>
> + if (mds >= mdsc->mdsmap->m_max_mds)
> + return ERR_PTR(-EINVAL);
> +
> s = kzalloc(sizeof(*s), GFP_NOFS);
> if (!s)
> return ERR_PTR(-ENOMEM);
>
>
> --
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