From 9f5325aa37279d724e064d32a95e13231c0ade23 Mon Sep 17 00:00:00 2001 From: Marcos Paulo de Souza Date: Tue, 6 Feb 2018 15:39:30 -0800 Subject: kernel/fork.c: check error and return early Thus reducing one indentation level while maintaining the same rationale. Link: http://lkml.kernel.org/r/20171117002929.5155-1-marcos.souza.org@gmail.com Signed-off-by: Marcos Paulo de Souza Acked-by: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 51 +++++++++++++++++++++++++-------------------------- 1 file changed, 25 insertions(+), 26 deletions(-) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index 5c372c954f3b..0d62524c6660 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2062,6 +2062,8 @@ long _do_fork(unsigned long clone_flags, int __user *child_tidptr, unsigned long tls) { + struct completion vfork; + struct pid *pid; struct task_struct *p; int trace = 0; long nr; @@ -2087,43 +2089,40 @@ long _do_fork(unsigned long clone_flags, p = copy_process(clone_flags, stack_start, stack_size, child_tidptr, NULL, trace, tls, NUMA_NO_NODE); add_latent_entropy(); + + if (IS_ERR(p)) + return PTR_ERR(p); + /* * Do this prior waking up the new thread - the thread pointer * might get invalid after that point, if the thread exits quickly. */ - if (!IS_ERR(p)) { - struct completion vfork; - struct pid *pid; - - trace_sched_process_fork(current, p); + trace_sched_process_fork(current, p); - pid = get_task_pid(p, PIDTYPE_PID); - nr = pid_vnr(pid); + pid = get_task_pid(p, PIDTYPE_PID); + nr = pid_vnr(pid); - if (clone_flags & CLONE_PARENT_SETTID) - put_user(nr, parent_tidptr); - - if (clone_flags & CLONE_VFORK) { - p->vfork_done = &vfork; - init_completion(&vfork); - get_task_struct(p); - } + if (clone_flags & CLONE_PARENT_SETTID) + put_user(nr, parent_tidptr); - wake_up_new_task(p); + if (clone_flags & CLONE_VFORK) { + p->vfork_done = &vfork; + init_completion(&vfork); + get_task_struct(p); + } - /* forking complete and child started to run, tell ptracer */ - if (unlikely(trace)) - ptrace_event_pid(trace, pid); + wake_up_new_task(p); - if (clone_flags & CLONE_VFORK) { - if (!wait_for_vfork_done(p, &vfork)) - ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid); - } + /* forking complete and child started to run, tell ptracer */ + if (unlikely(trace)) + ptrace_event_pid(trace, pid); - put_pid(pid); - } else { - nr = PTR_ERR(p); + if (clone_flags & CLONE_VFORK) { + if (!wait_for_vfork_done(p, &vfork)) + ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid); } + + put_pid(pid); return nr; } -- cgit v1.2.3-70-g09d2 From 667b60946ef9b8375085c7b225229923c6f87308 Mon Sep 17 00:00:00 2001 From: Marcos Paulo de Souza Date: Tue, 6 Feb 2018 15:39:34 -0800 Subject: kernel/fork.c: add comment about usage of CLONE_FS flags and namespaces All other places that deals with namespaces have an explanation of why the restriction is there. The description added in this commit was based on commit e66eded8309e ("userns: Don't allow CLONE_NEWUSER | CLONE_FS"). Link: http://lkml.kernel.org/r/20171112151637.13258-1-marcos.souza.org@gmail.com Signed-off-by: Marcos Paulo de Souza Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index 0d62524c6660..b9d857fe2a5c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1587,6 +1587,10 @@ static __latent_entropy struct task_struct *copy_process( int retval; struct task_struct *p; + /* + * Don't allow sharing the root directory with processes in a different + * namespace + */ if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) return ERR_PTR(-EINVAL); -- cgit v1.2.3-70-g09d2