diff options
| author | Aleksa Sarai <asarai@suse.com> | 2017-08-06 14:41:41 +1000 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-08-10 12:18:19 +0200 |
| commit | 74dc3384fc7983b78cc46ebb1824968a3db85eb1 (patch) | |
| tree | e896440f183791c28162dd72dfb60470aac80d16 | |
| parent | 18f08dae19990f5fffde92e3a63e0d90cda0f1a8 (diff) | |
| download | linux-74dc3384fc7983b78cc46ebb1824968a3db85eb1.tar.bz2 | |
sched/debug: Use task_pid_nr_ns in /proc/$pid/sched
It appears as though the addition of the PID namespace did not update
the output code for /proc/*/sched, which resulted in it providing PIDs
that were not self-consistent with the /proc mount. This additionally
made it trivial to detect whether a process was inside &init_pid_ns from
userspace, making container detection trivial:
https://github.com/jessfraz/amicontained
This leads to situations such as:
% unshare -pmf
% mount -t proc proc /proc
% head -n1 /proc/1/sched
head (10047, #threads: 1)
Fix this by just using task_pid_nr_ns for the output of /proc/*/sched.
All of the other uses of task_pid_nr in kernel/sched/debug.c are from a
sysctl context and thus don't need to be namespaced.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jess Frazelle <acidburn@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: cyphar@cyphar.com
Link: http://lkml.kernel.org/r/20170806044141.5093-1-asarai@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | fs/proc/base.c | 3 | ||||
| -rw-r--r-- | include/linux/sched/debug.h | 4 | ||||
| -rw-r--r-- | kernel/sched/debug.c | 5 |
3 files changed, 8 insertions, 4 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 719c2e943ea1..98fd8f6df851 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1408,12 +1408,13 @@ static const struct file_operations proc_fail_nth_operations = { static int sched_show(struct seq_file *m, void *v) { struct inode *inode = m->private; + struct pid_namespace *ns = inode->i_sb->s_fs_info; struct task_struct *p; p = get_proc_task(inode); if (!p) return -ESRCH; - proc_sched_show_task(p, m); + proc_sched_show_task(p, ns, m); put_task_struct(p); diff --git a/include/linux/sched/debug.h b/include/linux/sched/debug.h index e0eaee54c5a4..5d58d49e9f87 100644 --- a/include/linux/sched/debug.h +++ b/include/linux/sched/debug.h @@ -6,6 +6,7 @@ */ struct task_struct; +struct pid_namespace; extern void dump_cpu_task(int cpu); @@ -34,7 +35,8 @@ extern void sched_show_task(struct task_struct *p); #ifdef CONFIG_SCHED_DEBUG struct seq_file; -extern void proc_sched_show_task(struct task_struct *p, struct seq_file *m); +extern void proc_sched_show_task(struct task_struct *p, + struct pid_namespace *ns, struct seq_file *m); extern void proc_sched_set_task(struct task_struct *p); #endif diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 4fa66de52bd6..ac345115877b 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -872,11 +872,12 @@ static void sched_show_numa(struct task_struct *p, struct seq_file *m) #endif } -void proc_sched_show_task(struct task_struct *p, struct seq_file *m) +void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns, + struct seq_file *m) { unsigned long nr_switches; - SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr(p), + SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr_ns(p, ns), get_nr_threads(p)); SEQ_printf(m, "---------------------------------------------------------" |