diff options
-rw-r--r-- | fs/proc/base.c | 94 | ||||
-rw-r--r-- | include/linux/time_namespace.h | 10 | ||||
-rw-r--r-- | kernel/time/namespace.c | 101 |
3 files changed, 205 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index ebea9501afb8..5adc6390ac3a 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -94,6 +94,7 @@ #include <linux/sched/debug.h> #include <linux/sched/stat.h> #include <linux/posix-timers.h> +#include <linux/time_namespace.h> #include <trace/events/oom.h> #include "internal.h" #include "fd.h" @@ -1533,6 +1534,96 @@ static const struct file_operations proc_pid_sched_autogroup_operations = { #endif /* CONFIG_SCHED_AUTOGROUP */ +#ifdef CONFIG_TIME_NS +static int timens_offsets_show(struct seq_file *m, void *v) +{ + struct task_struct *p; + + p = get_proc_task(file_inode(m->file)); + if (!p) + return -ESRCH; + proc_timens_show_offsets(p, m); + + put_task_struct(p); + + return 0; +} + +static ssize_t timens_offsets_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file_inode(file); + struct proc_timens_offset offsets[2]; + char *kbuf = NULL, *pos, *next_line; + struct task_struct *p; + int ret, noffsets; + + /* Only allow < page size writes at the beginning of the file */ + if ((*ppos != 0) || (count >= PAGE_SIZE)) + return -EINVAL; + + /* Slurp in the user data */ + kbuf = memdup_user_nul(buf, count); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + /* Parse the user data */ + ret = -EINVAL; + noffsets = 0; + for (pos = kbuf; pos; pos = next_line) { + struct proc_timens_offset *off = &offsets[noffsets]; + int err; + + /* Find the end of line and ensure we don't look past it */ + next_line = strchr(pos, '\n'); + if (next_line) { + *next_line = '\0'; + next_line++; + if (*next_line == '\0') + next_line = NULL; + } + + err = sscanf(pos, "%u %lld %lu", &off->clockid, + &off->val.tv_sec, &off->val.tv_nsec); + if (err != 3 || off->val.tv_nsec >= NSEC_PER_SEC) + goto out; + noffsets++; + if (noffsets == ARRAY_SIZE(offsets)) { + if (next_line) + count = next_line - kbuf; + break; + } + } + + ret = -ESRCH; + p = get_proc_task(inode); + if (!p) + goto out; + ret = proc_timens_set_offset(file, p, offsets, noffsets); + put_task_struct(p); + if (ret) + goto out; + + ret = count; +out: + kfree(kbuf); + return ret; +} + +static int timens_offsets_open(struct inode *inode, struct file *filp) +{ + return single_open(filp, timens_offsets_show, inode); +} + +static const struct file_operations proc_timens_offsets_operations = { + .open = timens_offsets_open, + .read = seq_read, + .write = timens_offsets_write, + .llseek = seq_lseek, + .release = single_release, +}; +#endif /* CONFIG_TIME_NS */ + static ssize_t comm_write(struct file *file, const char __user *buf, size_t count, loff_t *offset) { @@ -3016,6 +3107,9 @@ static const struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_SCHED_AUTOGROUP REG("autogroup", S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations), #endif +#ifdef CONFIG_TIME_NS + REG("timens_offsets", S_IRUGO|S_IWUSR, proc_timens_offsets_operations), +#endif REG("comm", S_IRUGO|S_IWUSR, proc_pid_set_comm_operations), #ifdef CONFIG_HAVE_ARCH_TRACEHOOK ONE("syscall", S_IRUSR, proc_pid_syscall), diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h index 04a2ba8b8a06..824d54e057eb 100644 --- a/include/linux/time_namespace.h +++ b/include/linux/time_namespace.h @@ -52,6 +52,16 @@ static inline void put_time_ns(struct time_namespace *ns) kref_put(&ns->kref, free_time_ns); } +void proc_timens_show_offsets(struct task_struct *p, struct seq_file *m); + +struct proc_timens_offset { + int clockid; + struct timespec64 val; +}; + +int proc_timens_set_offset(struct file *file, struct task_struct *p, + struct proc_timens_offset *offsets, int n); + static inline void timens_add_monotonic(struct timespec64 *ts) { struct timens_offsets *ns_offsets = ¤t->nsproxy->time_ns->offsets; diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c index 0732964803b9..12858507d75a 100644 --- a/kernel/time/namespace.c +++ b/kernel/time/namespace.c @@ -8,6 +8,7 @@ #include <linux/user_namespace.h> #include <linux/sched/signal.h> #include <linux/sched/task.h> +#include <linux/seq_file.h> #include <linux/proc_ns.h> #include <linux/export.h> #include <linux/time.h> @@ -334,6 +335,106 @@ static struct user_namespace *timens_owner(struct ns_common *ns) return to_time_ns(ns)->user_ns; } +static void show_offset(struct seq_file *m, int clockid, struct timespec64 *ts) +{ + seq_printf(m, "%d %lld %ld\n", clockid, ts->tv_sec, ts->tv_nsec); +} + +void proc_timens_show_offsets(struct task_struct *p, struct seq_file *m) +{ + struct ns_common *ns; + struct time_namespace *time_ns; + + ns = timens_for_children_get(p); + if (!ns) + return; + time_ns = to_time_ns(ns); + + show_offset(m, CLOCK_MONOTONIC, &time_ns->offsets.monotonic); + show_offset(m, CLOCK_BOOTTIME, &time_ns->offsets.boottime); + put_time_ns(time_ns); +} + +int proc_timens_set_offset(struct file *file, struct task_struct *p, + struct proc_timens_offset *offsets, int noffsets) +{ + struct ns_common *ns; + struct time_namespace *time_ns; + struct timespec64 tp; + int i, err; + + ns = timens_for_children_get(p); + if (!ns) + return -ESRCH; + time_ns = to_time_ns(ns); + + if (!file_ns_capable(file, time_ns->user_ns, CAP_SYS_TIME)) { + put_time_ns(time_ns); + return -EPERM; + } + + for (i = 0; i < noffsets; i++) { + struct proc_timens_offset *off = &offsets[i]; + + switch (off->clockid) { + case CLOCK_MONOTONIC: + ktime_get_ts64(&tp); + break; + case CLOCK_BOOTTIME: + ktime_get_boottime_ts64(&tp); + break; + default: + err = -EINVAL; + goto out; + } + + err = -ERANGE; + + if (off->val.tv_sec > KTIME_SEC_MAX || + off->val.tv_sec < -KTIME_SEC_MAX) + goto out; + + tp = timespec64_add(tp, off->val); + /* + * KTIME_SEC_MAX is divided by 2 to be sure that KTIME_MAX is + * still unreachable. + */ + if (tp.tv_sec < 0 || tp.tv_sec > KTIME_SEC_MAX / 2) + goto out; + } + + mutex_lock(&offset_lock); + if (time_ns->frozen_offsets) { + err = -EACCES; + goto out_unlock; + } + + err = 0; + /* Don't report errors after this line */ + for (i = 0; i < noffsets; i++) { + struct proc_timens_offset *off = &offsets[i]; + struct timespec64 *offset = NULL; + + switch (off->clockid) { + case CLOCK_MONOTONIC: + offset = &time_ns->offsets.monotonic; + break; + case CLOCK_BOOTTIME: + offset = &time_ns->offsets.boottime; + break; + } + + *offset = off->val; + } + +out_unlock: + mutex_unlock(&offset_lock); +out: + put_time_ns(time_ns); + + return err; +} + const struct proc_ns_operations timens_operations = { .name = "time", .type = CLONE_NEWTIME, |