From: Mark Salyzyn <salyzyn@android.com>
To: linux-kernel@vger.kernel.org
Cc: Mark Salyzyn <salyzyn@android.com>,
Miklos Szeredi <miklos@szeredi.hu>,
Jonathan Corbet <corbet@lwn.net>, Vivek Goyal <vgoyal@redhat.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Amir Goldstein <amir73il@gmail.com>,
Randy Dunlap <rdunlap@infradead.org>,
Stephen Smalley <sds@tycho.nsa.gov>,
linux-unionfs@vger.kernel.org, linux-doc@vger.kernel.org
Subject: [PATCH v5 1/3] overlayfs: check CAP_DAC_READ_SEARCH before issuing exportfs_decode_fh
Date: Tue, 28 Aug 2018 09:52:56 -0700 [thread overview]
Message-ID: <20180828165259.211474-1-salyzyn@android.com> (raw)
Assumption never checked, should fail if the mounter creds are not
sufficient.
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: linux-unionfs@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
v5:
- dependency of "overlayfs: override_creds=off option bypass creator_cred"
---
fs/overlayfs/namei.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index c993dd8db739..84982b6525fb 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -193,6 +193,11 @@ struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
if (!uuid_equal(&fh->uuid, &mnt->mnt_sb->s_uuid))
return NULL;
+ if (!capable(CAP_DAC_READ_SEARCH)) {
+ origin = ERR_PTR(-EPERM);
+ goto out;
+ }
+
bytes = (fh->len - offsetof(struct ovl_fh, fid));
real = exportfs_decode_fh(mnt, (struct fid *)fh->fid,
bytes >> 2, (int)fh->type,
--
2.19.0.rc0.228.g281dcd1b4d0-goog
next reply other threads:[~2018-08-28 16:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-28 16:52 Mark Salyzyn [this message]
2018-08-28 17:34 ` [PATCH v5 1/3] overlayfs: check CAP_DAC_READ_SEARCH before issuing exportfs_decode_fh Amir Goldstein
2018-08-28 17:44 ` Mark Salyzyn
2018-08-28 18:40 ` Amir Goldstein
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