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userns: user namespaces: convert several capable() calls

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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>
This commit is contained in:
Serge E. Hallyn
2011-03-23 16:43:24 -07:00
committed by Linus Torvalds
parent b515498f5b
commit b0e77598f8
13 changed files with 75 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
kernel/futex.c
View File

@@ -2418,10 +2418,19 @@ 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();
}

11
kernel/futex_compat.c
View File

@@ -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();
}

2
kernel/groups.c
View File

@@ -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;

7
kernel/nsproxy.c
View File

@@ -75,16 +75,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
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)) {

9
kernel/sched.c
View File

@@ -4892,8 +4892,11 @@ 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;
}
@@ -5221,7 +5224,7 @@ 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);

2
kernel/uid16.c
View File

@@ -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;