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 <serge.hallyn@canonical.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index d3c32dc..a6d1655 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -5,6 +5,7 @@
#include <linux/idr.h>
#include <linux/rwsem.h>
#include <linux/notifier.h>
+#include <linux/nsproxy.h>
/*
* ipc namespace events
@@ -93,7 +94,7 @@
#if defined(CONFIG_IPC_NS)
extern struct ipc_namespace *copy_ipcs(unsigned long flags,
- struct ipc_namespace *ns);
+ struct task_struct *tsk);
static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
{
if (ns)
@@ -104,12 +105,12 @@
extern void put_ipc_ns(struct ipc_namespace *ns);
#else
static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
- struct ipc_namespace *ns)
+ struct task_struct *tsk)
{
if (flags & CLONE_NEWIPC)
return ERR_PTR(-EINVAL);
- return ns;
+ return tsk->nsproxy->ipc_ns;
}
static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
diff --git a/ipc/msg.c b/ipc/msg.c
index 747b655..0e732e9 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -421,7 +421,7 @@
return -EFAULT;
}
- ipcp = ipcctl_pre_down(&msg_ids(ns), msqid, cmd,
+ ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid, cmd,
&msqid64.msg_perm, msqid64.msg_qbytes);
if (IS_ERR(ipcp))
return PTR_ERR(ipcp);
@@ -539,7 +539,7 @@
success_return = 0;
}
err = -EACCES;
- if (ipcperms(&msq->q_perm, S_IRUGO))
+ if (ipcperms(ns, &msq->q_perm, S_IRUGO))
goto out_unlock;
err = security_msg_queue_msgctl(msq, cmd);
@@ -664,7 +664,7 @@
struct msg_sender s;
err = -EACCES;
- if (ipcperms(&msq->q_perm, S_IWUGO))
+ if (ipcperms(ns, &msq->q_perm, S_IWUGO))
goto out_unlock_free;
err = security_msg_queue_msgsnd(msq, msg, msgflg);
@@ -774,7 +774,7 @@
struct list_head *tmp;
msg = ERR_PTR(-EACCES);
- if (ipcperms(&msq->q_perm, S_IRUGO))
+ if (ipcperms(ns, &msq->q_perm, S_IRUGO))
goto out_unlock;
msg = ERR_PTR(-EAGAIN);
diff --git a/ipc/namespace.c b/ipc/namespace.c
index aa18899..3c3e522 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 @@
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);
}
/*
diff --git a/ipc/sem.c b/ipc/sem.c
index 0e0d49b..ae040a0 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -817,7 +817,7 @@
}
err = -EACCES;
- if (ipcperms (&sma->sem_perm, S_IRUGO))
+ if (ipcperms(ns, &sma->sem_perm, S_IRUGO))
goto out_unlock;
err = security_sem_semctl(sma, cmd);
@@ -862,7 +862,8 @@
nsems = sma->sem_nsems;
err = -EACCES;
- if (ipcperms (&sma->sem_perm, (cmd==SETVAL||cmd==SETALL)?S_IWUGO:S_IRUGO))
+ if (ipcperms(ns, &sma->sem_perm,
+ (cmd == SETVAL || cmd == SETALL) ? S_IWUGO : S_IRUGO))
goto out_unlock;
err = security_sem_semctl(sma, cmd);
@@ -1047,7 +1048,8 @@
return -EFAULT;
}
- ipcp = ipcctl_pre_down(&sem_ids(ns), semid, cmd, &semid64.sem_perm, 0);
+ ipcp = ipcctl_pre_down(ns, &sem_ids(ns), semid, cmd,
+ &semid64.sem_perm, 0);
if (IS_ERR(ipcp))
return PTR_ERR(ipcp);
@@ -1386,7 +1388,7 @@
goto out_unlock_free;
error = -EACCES;
- if (ipcperms(&sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
+ if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
goto out_unlock_free;
error = security_sem_semop(sma, sops, nsops, alter);
diff --git a/ipc/shm.c b/ipc/shm.c
index 7d3bb22..8644452 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -623,7 +623,8 @@
return -EFAULT;
}
- ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
+ ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
+ &shmid64.shm_perm, 0);
if (IS_ERR(ipcp))
return PTR_ERR(ipcp);
@@ -737,7 +738,7 @@
result = 0;
}
err = -EACCES;
- if (ipcperms (&shp->shm_perm, S_IRUGO))
+ if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
goto out_unlock;
err = security_shm_shmctl(shp, cmd);
if (err)
@@ -773,7 +774,7 @@
audit_ipc_obj(&(shp->shm_perm));
- if (!capable(CAP_IPC_LOCK)) {
+ if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
uid_t euid = current_euid();
err = -EPERM;
if (euid != shp->shm_perm.uid &&
@@ -888,7 +889,7 @@
}
err = -EACCES;
- if (ipcperms(&shp->shm_perm, acc_mode))
+ if (ipcperms(ns, &shp->shm_perm, acc_mode))
goto out_unlock;
err = security_shm_shmat(shp, shmaddr, shmflg);
diff --git a/ipc/util.c b/ipc/util.c
index 69a0cc1..8fd1b89 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -329,12 +329,14 @@
*
* It is called with ipc_ids.rw_mutex and ipcp->lock held.
*/
-static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops,
- struct ipc_params *params)
+static int ipc_check_perms(struct ipc_namespace *ns,
+ struct kern_ipc_perm *ipcp,
+ struct ipc_ops *ops,
+ struct ipc_params *params)
{
int err;
- if (ipcperms(ipcp, params->flg))
+ if (ipcperms(ns, ipcp, params->flg))
err = -EACCES;
else {
err = ops->associate(ipcp, params->flg);
@@ -396,7 +398,7 @@
* ipc_check_perms returns the IPC id on
* success
*/
- err = ipc_check_perms(ipcp, ops, params);
+ err = ipc_check_perms(ns, ipcp, ops, params);
}
ipc_unlock(ipcp);
}
@@ -610,10 +612,12 @@
*
* Check user, group, other permissions for access
* to ipc resources. return 0 if allowed
+ *
+ * @flag will most probably be 0 or S_...UGO from <linux/stat.h>
*/
-int ipcperms (struct kern_ipc_perm *ipcp, short flag)
-{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
+int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag)
+{
uid_t euid = current_euid();
int requested_mode, granted_mode;
@@ -627,7 +631,7 @@
granted_mode >>= 3;
/* is there some bit set in requested_mode but not in granted_mode? */
if ((requested_mode & ~granted_mode & 0007) &&
- !capable(CAP_IPC_OWNER))
+ !ns_capable(ns->user_ns, CAP_IPC_OWNER))
return -1;
return security_ipc_permission(ipcp, flag);
@@ -765,6 +769,7 @@
/**
* ipcctl_pre_down - retrieve an ipc and check permissions for some IPC_XXX cmd
+ * @ids: the ipc namespace
* @ids: the table of ids where to look for the ipc
* @id: the id of the ipc to retrieve
* @cmd: the cmd to check
@@ -779,7 +784,8 @@
* - returns the ipc with both ipc and rw_mutex locks held in case of success
* or an err-code without any lock held otherwise.
*/
-struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
+struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
+ struct ipc_ids *ids, int id, int cmd,
struct ipc64_perm *perm, int extra_perm)
{
struct kern_ipc_perm *ipcp;
@@ -799,8 +805,8 @@
perm->gid, perm->mode);
euid = current_euid();
- if (euid == ipcp->cuid ||
- euid == ipcp->uid || capable(CAP_SYS_ADMIN))
+ if (euid == ipcp->cuid || euid == ipcp->uid ||
+ ns_capable(ns->user_ns, CAP_SYS_ADMIN))
return ipcp;
err = -EPERM;
diff --git a/ipc/util.h b/ipc/util.h
index 764b51a..6f5c20b 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -103,7 +103,7 @@
void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
/* must be called with ipcp locked */
-int ipcperms(struct kern_ipc_perm *ipcp, short flg);
+int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
/* for rare, potentially huge allocations.
* both function can sleep
@@ -126,7 +126,8 @@
void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
-struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
+struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
+ struct ipc_ids *ids, int id, int cmd,
struct ipc64_perm *perm, int extra_perm);
#ifndef __ARCH_WANT_IPC_PARSE_VERSION
diff --git a/kernel/futex.c b/kernel/futex.c
index bda4157..6570c459f 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2418,10 +2418,19 @@
goto err_unlock;
ret = -EPERM;
pcred = __task_cred(p);
+ /* If victim is in different user_ns, then uids are not
+ comparable, so we must have CAP_SYS_PTRACE */
+ if (cred->user->user_ns != pcred->user->user_ns) {
+ if (!ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
+ goto err_unlock;
+ goto ok;
+ }
+ /* If victim is in same user_ns, then uids are comparable */
if (cred->euid != pcred->euid &&
cred->euid != pcred->uid &&
- !capable(CAP_SYS_PTRACE))
+ !ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
goto err_unlock;
+ok:
head = p->robust_list;
rcu_read_unlock();
}
diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
index a7934ac..5f9e689 100644
--- a/kernel/futex_compat.c
+++ b/kernel/futex_compat.c
@@ -153,10 +153,19 @@
goto err_unlock;
ret = -EPERM;
pcred = __task_cred(p);
+ /* If victim is in different user_ns, then uids are not
+ comparable, so we must have CAP_SYS_PTRACE */
+ if (cred->user->user_ns != pcred->user->user_ns) {
+ if (!ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
+ goto err_unlock;
+ goto ok;
+ }
+ /* If victim is in same user_ns, then uids are comparable */
if (cred->euid != pcred->euid &&
cred->euid != pcred->uid &&
- !capable(CAP_SYS_PTRACE))
+ !ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
goto err_unlock;
+ok:
head = p->compat_robust_list;
rcu_read_unlock();
}
diff --git a/kernel/groups.c b/kernel/groups.c
index 253dc0f..1cc476d 100644
--- a/kernel/groups.c
+++ b/kernel/groups.c
@@ -233,7 +233,7 @@
struct group_info *group_info;
int retval;
- if (!capable(CAP_SETGID))
+ if (!nsown_capable(CAP_SETGID))
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ac8a56e..a05d191 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -75,16 +75,11 @@
goto out_uts;
}
- new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
+ new_nsp->ipc_ns = copy_ipcs(flags, tsk);
if (IS_ERR(new_nsp->ipc_ns)) {
err = PTR_ERR(new_nsp->ipc_ns);
goto out_ipc;
}
- if (new_nsp->ipc_ns != tsk->nsproxy->ipc_ns) {
- put_user_ns(new_nsp->ipc_ns->user_ns);
- new_nsp->ipc_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
- get_user_ns(new_nsp->ipc_ns->user_ns);
- }
new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
if (IS_ERR(new_nsp->pid_ns)) {
diff --git a/kernel/sched.c b/kernel/sched.c
index a172494..480adeb 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4892,8 +4892,11 @@
rcu_read_lock();
pcred = __task_cred(p);
- match = (cred->euid == pcred->euid ||
- cred->euid == pcred->uid);
+ if (cred->user->user_ns == pcred->user->user_ns)
+ match = (cred->euid == pcred->euid ||
+ cred->euid == pcred->uid);
+ else
+ match = false;
rcu_read_unlock();
return match;
}
@@ -5221,7 +5224,7 @@
goto out_free_cpus_allowed;
}
retval = -EPERM;
- if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
+ if (!check_same_owner(p) && !task_ns_capable(p, CAP_SYS_NICE))
goto out_unlock;
retval = security_task_setscheduler(p);
diff --git a/kernel/uid16.c b/kernel/uid16.c
index 4192098..51c6e89 100644
--- a/kernel/uid16.c
+++ b/kernel/uid16.c
@@ -189,7 +189,7 @@
struct group_info *group_info;
int retval;
- if (!capable(CAP_SETGID))
+ if (!nsown_capable(CAP_SETGID))
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;