Messages in this thread Patch in this message | | | From | Mark Salyzyn <> | Subject | [PATCH v10 1/5] overlayfs: check CAP_DAC_READ_SEARCH before issuing exportfs_decode_fh | Date | Wed, 24 Jul 2019 12:57:12 -0700 |
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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 Cc: kernel-team@android.com --- v10: - return NULL rather than ERR_PTR(-EPERM) - did _not_ add it ovl_can_decode_fh() because of changes since last review, suspect needs to be added to ovl_lower_uuid_ok()?
v8 + v9: - rebase
v7: - This time for realz
v6: - rebase
v5: - dependency of "overlayfs: override_creds=off option bypass creator_cred" --- fs/overlayfs/namei.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index e9717c2f7d45..9702f0d5309d 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -161,6 +161,9 @@ 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)) + return NULL; + bytes = (fh->len - offsetof(struct ovl_fh, fid)); real = exportfs_decode_fh(mnt, (struct fid *)fh->fid, bytes >> 2, (int)fh->type, -- 2.22.0.657.g960e92d24f-goog
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