diff options
| author | Christian Brauner <brauner@kernel.org> | 2026-02-26 16:51:00 +0300 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-03-12 01:15:15 +0300 |
| commit | 24baca56fafc33d4fb77cd9858a48c734183cb22 (patch) | |
| tree | 8b819c9a038a0ef57c94547e49e525ed31959e72 | |
| parent | 12ae2c81b21cfaa193db2faf035d495807edc3a7 (diff) | |
| download | linux-24baca56fafc33d4fb77cd9858a48c734183cb22.tar.xz | |
clone: add CLONE_NNP
Add a new clone3() flag CLONE_NNP that sets no_new_privs on the child
process at clone time. This is analogous to prctl(PR_SET_NO_NEW_PRIVS)
but applied at process creation rather than requiring a separate step
after the child starts running.
CLONE_NNP is rejected with CLONE_THREAD. It's conceptually a lot simpler
if the whole thread-group is forced into NNP and not have single threads
running around with NNP.
Link: https://patch.msgid.link/20260226-work-pidfs-autoreap-v5-2-d148b984a989@kernel.org
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
| -rw-r--r-- | include/uapi/linux/sched.h | 1 | ||||
| -rw-r--r-- | kernel/fork.c | 10 |
2 files changed, 10 insertions, 1 deletions
diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h index 69f7b4f9eb0c..386c8d7e89cb 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -37,6 +37,7 @@ #define CLONE_CLEAR_SIGHAND (1ULL << 32) /* Clear any signal handler and reset to SIG_DFL. */ #define CLONE_INTO_CGROUP (1ULL << 33) /* Clone into a specific cgroup given the right permissions. */ #define CLONE_AUTOREAP (1ULL << 34) /* Auto-reap child on exit. */ +#define CLONE_NNP (1ULL << 35) /* Set no_new_privs on child. */ /* * cloning flags intersect with CSIGNAL so can be used with unshare and clone3 diff --git a/kernel/fork.c b/kernel/fork.c index 10549574fda6..736798e4005a 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2040,6 +2040,11 @@ __latent_entropy struct task_struct *copy_process( if ((clone_flags & CLONE_PARENT) && current->signal->autoreap) return ERR_PTR(-EINVAL); + if (clone_flags & CLONE_NNP) { + if (clone_flags & CLONE_THREAD) + return ERR_PTR(-EINVAL); + } + /* * Force any signals received before this point to be delivered * before the fork happens. Collect up signals sent to multiple @@ -2424,6 +2429,9 @@ __latent_entropy struct task_struct *copy_process( */ copy_seccomp(p); + if (clone_flags & CLONE_NNP) + task_set_no_new_privs(p); + init_task_pid_links(p); if (likely(p->pid)) { ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); @@ -2912,7 +2920,7 @@ static bool clone3_args_valid(struct kernel_clone_args *kargs) /* Verify that no unknown flags are passed along. */ if (kargs->flags & ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP | - CLONE_AUTOREAP)) + CLONE_AUTOREAP | CLONE_NNP)) return false; /* |