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Message-ID: <20110217150356.GH26395@mail.hallyn.com>
Date: Thu, 17 Feb 2011 15:03:56 +0000
From: "Serge E. Hallyn" <serge@...lyn.com>
To: "Serge E. Hallyn" <serge@...lyn.com>
Cc: LSM <linux-security-module@...r.kernel.org>,
Andrew Morton <akpm@...l.org>,
James Morris <jmorris@...ei.org>,
Kees Cook <kees.cook@...onical.com>,
containers@...ts.linux-foundation.org,
kernel list <linux-kernel@...r.kernel.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Alexey Dobriyan <adobriyan@...il.com>,
Michael Kerrisk <mtk.manpages@...il.com>, xemul@...allels.com,
dhowells@...hat.com
Subject: [PATCH 8/9] 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
Signed-off-by: Serge E. Hallyn <serge.hallyn@...onical.com>
---
ipc/shm.c | 2 +-
ipc/util.c | 5 +++--
kernel/futex.c | 11 ++++++++++-
kernel/futex_compat.c | 11 ++++++++++-
kernel/groups.c | 2 +-
kernel/sched.c | 9 ++++++---
kernel/uid16.c | 2 +-
7 files changed, 32 insertions(+), 10 deletions(-)
diff --git a/ipc/shm.c b/ipc/shm.c
index 7d3bb22..e91e2e9 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -773,7 +773,7 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
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 &&
diff --git a/ipc/util.c b/ipc/util.c
index 69a0cc1..8e7ec6a 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -627,7 +627,7 @@ int ipcperms (struct kern_ipc_perm *ipcp, short flag)
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(current->nsproxy->ipc_ns->user_ns, CAP_IPC_OWNER))
return -1;
return security_ipc_permission(ipcp, flag);
@@ -800,7 +800,8 @@ struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
euid = current_euid();
if (euid == ipcp->cuid ||
- euid == ipcp->uid || capable(CAP_SYS_ADMIN))
+ euid == ipcp->uid ||
+ ns_capable(current->nsproxy->ipc_ns->user_ns, CAP_SYS_ADMIN))
return ipcp;
err = -EPERM;
diff --git a/kernel/futex.c b/kernel/futex.c
index b766d28..1e876f1 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2421,10 +2421,19 @@ SYSCALL_DEFINE3(get_robust_list, int, pid,
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 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
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 @@ SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
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/sched.c b/kernel/sched.c
index 18d38e4..dc12bc2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4761,8 +4761,11 @@ static bool check_same_owner(struct task_struct *p)
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;
}
@@ -5088,7 +5091,7 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
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 @@ SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
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;
--
1.7.0.4
--
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