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| author | Al Viro <viro@zeniv.linux.org.uk> | 2017-04-15 17:31:22 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2017-04-21 14:05:36 -0400 |
| commit | 4f757f3cbf54edef7b75c68d6d6d2f1a0ca08d2e (patch) | |
| tree | ea39abd6e1941de602264b24ee18c82f12c01c04 /fs/namespace.c | |
| parent | 93893862fb7ba704ec5a6872a294c9cc2b0d4ca3 (diff) | |
| download | linux-4f757f3cbf54edef7b75c68d6d6d2f1a0ca08d2e.tar.gz linux-4f757f3cbf54edef7b75c68d6d6d2f1a0ca08d2e.tar.bz2 linux-4f757f3cbf54edef7b75c68d6d6d2f1a0ca08d2e.zip | |
make sure that mntns_install() doesn't end up with referral for root
new flag: LOOKUP_DOWN. If the starting point is overmounted, cross
into whatever's mounted on top, triggering referrals et.al.
Use that instead of follow_down_one() loop in mntns_install(), handle
errors properly.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index cc1375eff88c..0886ef28bff6 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3465,8 +3465,9 @@ static void mntns_put(struct ns_common *ns) static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns) { struct fs_struct *fs = current->fs; - struct mnt_namespace *mnt_ns = to_mnt_ns(ns); + struct mnt_namespace *mnt_ns = to_mnt_ns(ns), *old_mnt_ns; struct path root; + int err; if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) || !ns_capable(current_user_ns(), CAP_SYS_CHROOT) || @@ -3477,15 +3478,18 @@ static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns) return -EINVAL; get_mnt_ns(mnt_ns); - put_mnt_ns(nsproxy->mnt_ns); + old_mnt_ns = nsproxy->mnt_ns; nsproxy->mnt_ns = mnt_ns; /* Find the root */ - root.mnt = &mnt_ns->root->mnt; - root.dentry = mnt_ns->root->mnt.mnt_root; - path_get(&root); - while(d_mountpoint(root.dentry) && follow_down_one(&root)) - ; + err = vfs_path_lookup(mnt_ns->root->mnt.mnt_root, &mnt_ns->root->mnt, + "/", LOOKUP_DOWN, &root); + if (err) { + /* revert to old namespace */ + nsproxy->mnt_ns = old_mnt_ns; + put_mnt_ns(mnt_ns); + return err; + } /* Update the pwd and root */ set_fs_pwd(fs, &root); |