From b515498f5bb5f38fc0e390b4ff7d00b6077de127 Mon Sep 17 00:00:00 2001 From: "Serge E. Hallyn" Date: Wed, 23 Mar 2011 16:43:23 -0700 Subject: userns: add a user namespace owner of ipc ns Changelog: Feb 15: Don't set new ipc->user_ns if we didn't create a new ipc_ns. Feb 23: Move extern declaration to ipc_namespace.h, and group fwd declarations at top. Signed-off-by: Serge E. Hallyn Acked-by: "Eric W. Biederman" Acked-by: Daniel Lezcano Acked-by: David Howells Cc: James Morris Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/namespace.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'ipc/namespace.c') diff --git a/ipc/namespace.c b/ipc/namespace.c index a1094ff0befa..aa1889962693 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -11,10 +11,11 @@ #include #include #include +#include #include "util.h" -static struct ipc_namespace *create_ipc_ns(void) +static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns) { struct ipc_namespace *ns; int err; @@ -43,6 +44,9 @@ static struct ipc_namespace *create_ipc_ns(void) ipcns_notify(IPCNS_CREATED); register_ipcns_notifier(ns); + ns->user_ns = old_ns->user_ns; + get_user_ns(ns->user_ns); + return ns; } @@ -50,7 +54,7 @@ struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns) { if (!(flags & CLONE_NEWIPC)) return get_ipc_ns(ns); - return create_ipc_ns(); + return create_ipc_ns(ns); } /* @@ -105,6 +109,7 @@ static void free_ipc_ns(struct ipc_namespace *ns) * order to have a correct value when recomputing msgmni. */ ipcns_notify(IPCNS_REMOVED); + put_user_ns(ns->user_ns); } /* -- cgit From b0e77598f87107001a00b8a4ece9c95e4254ccc4 Mon Sep 17 00:00:00 2001 From: "Serge E. Hallyn" Date: Wed, 23 Mar 2011 16:43:24 -0700 Subject: userns: user namespaces: convert several capable() calls CAP_IPC_OWNER and CAP_IPC_LOCK can be checked against current_user_ns(), because the resource comes from current's own ipc namespace. setuid/setgid are to uids in own namespace, so again checks can be against current_user_ns(). Changelog: Jan 11: Use task_ns_capable() in place of sched_capable(). Jan 11: Use nsown_capable() as suggested by Bastian Blank. Jan 11: Clarify (hopefully) some logic in futex and sched.c Feb 15: use ns_capable for ipc, not nsown_capable Feb 23: let copy_ipcs handle setting ipc_ns->user_ns Feb 23: pass ns down rather than taking it from current [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Serge E. Hallyn Acked-by: "Eric W. Biederman" Acked-by: Daniel Lezcano Acked-by: David Howells Cc: James Morris Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/namespace.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'ipc/namespace.c') diff --git a/ipc/namespace.c b/ipc/namespace.c index aa1889962693..3c3e5223e7e5 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -15,7 +15,8 @@ #include "util.h" -static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns) +static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk, + struct ipc_namespace *old_ns) { struct ipc_namespace *ns; int err; @@ -44,17 +45,19 @@ static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns) ipcns_notify(IPCNS_CREATED); register_ipcns_notifier(ns); - ns->user_ns = old_ns->user_ns; - get_user_ns(ns->user_ns); + ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns); return ns; } -struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns) +struct ipc_namespace *copy_ipcs(unsigned long flags, + struct task_struct *tsk) { + struct ipc_namespace *ns = tsk->nsproxy->ipc_ns; + if (!(flags & CLONE_NEWIPC)) return get_ipc_ns(ns); - return create_ipc_ns(ns); + return create_ipc_ns(tsk, ns); } /* -- cgit From be4d250ab41e13f8f945be6896695e870b38ba31 Mon Sep 17 00:00:00 2001 From: Xiaotian Feng Date: Fri, 25 Mar 2011 01:57:01 -0700 Subject: ipcns: fix use after free in free_ipc_ns() commit b515498 ("userns: add a user namespace owner of ipc ns") added a user namespace owner of ipc ns, but it also introduced a use after free in free_ipc_ns(). Signed-off-by: Xiaotian Feng Acked-by: "Serge E. Hallyn" Acked-by: David Howells Cc: "Eric W. Biederman" Cc: Daniel Lezcano Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'ipc/namespace.c') diff --git a/ipc/namespace.c b/ipc/namespace.c index 3c3e5223e7e5..8054c8e5faf1 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -104,7 +104,6 @@ static void free_ipc_ns(struct ipc_namespace *ns) sem_exit_ns(ns); msg_exit_ns(ns); shm_exit_ns(ns); - kfree(ns); atomic_dec(&nr_ipc_ns); /* @@ -113,6 +112,7 @@ static void free_ipc_ns(struct ipc_namespace *ns) */ ipcns_notify(IPCNS_REMOVED); put_user_ns(ns->user_ns); + kfree(ns); } /* -- cgit