fix create_new_namespaces() return value

dup_mnt_ns() and clone_uts_ns() return NULL on failure.  This is wrong,
create_new_namespaces() uses ERR_PTR() to catch an error.  This means that the
subsequent create_new_namespaces() will hit BUG_ON() in copy_mnt_ns() or
copy_utsname().

Modify create_new_namespaces() to also use the errors returned by the
copy_*_ns routines and not to systematically return ENOMEM.

[oleg@tv-sign.ru: better changelog]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 6 deletions

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 5aa28e219487..15a6015a849d 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -58,30 +58,41 @@ static struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk,
                         struct fs_struct *new_fs)
 {
         struct nsproxy *new_nsp;
+        int err;
 
         new_nsp = clone_nsproxy(tsk->nsproxy);
         if (!new_nsp)
                 return ERR_PTR(-ENOMEM);
 
         new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
-        if (IS_ERR(new_nsp->mnt_ns))
+        if (IS_ERR(new_nsp->mnt_ns)) {
+                err = PTR_ERR(new_nsp->mnt_ns);
                 goto out_ns;
+        }
 
         new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
-        if (IS_ERR(new_nsp->uts_ns))
+        if (IS_ERR(new_nsp->uts_ns)) {
+                err = PTR_ERR(new_nsp->uts_ns);
                 goto out_uts;
+        }
 
         new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
-        if (IS_ERR(new_nsp->ipc_ns))
+        if (IS_ERR(new_nsp->ipc_ns)) {
+                err = PTR_ERR(new_nsp->ipc_ns);
                 goto out_ipc;
+        }
 
         new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
-        if (IS_ERR(new_nsp->pid_ns))
+        if (IS_ERR(new_nsp->pid_ns)) {
+                err = PTR_ERR(new_nsp->pid_ns);
                 goto out_pid;
+        }
 
         new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns);
-        if (IS_ERR(new_nsp->user_ns))
+        if (IS_ERR(new_nsp->user_ns)) {
+                err = PTR_ERR(new_nsp->user_ns);
                 goto out_user;
+        }
 
         return new_nsp;
 
@@ -99,7 +110,7 @@ out_uts:
                 put_mnt_ns(new_nsp->mnt_ns);
 out_ns:
         kfree(new_nsp);
-        return ERR_PTR(-ENOMEM);
+        return ERR_PTR(err);
 }
 
 /*