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 --- kernel/futex.c | 11 ++++++++++- kernel/futex_compat.c | 11 ++++++++++- kernel/groups.c | 2 +- kernel/nsproxy.c | 7 +------ kernel/sched.c | 9 ++++++--- kernel/uid16.c | 2 +- 6 files changed, 29 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index bda415715382..6570c459f31c 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -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(); } diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c index a7934ac75e5b..5f9e689dc8f0 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 253dc0f35cf4..1cc476d52dd3 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/nsproxy.c b/kernel/nsproxy.c index ac8a56e90bf8..a05d191ffdd9 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -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)) { diff --git a/kernel/sched.c b/kernel/sched.c index a172494a9a63..480adeb63f8f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -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); diff --git a/kernel/uid16.c b/kernel/uid16.c index 419209893d87..51c6e89e8619 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; -- cgit v1.2.3