diff options
Diffstat (limited to 'fs/proc/base.c')
| -rw-r--r-- | fs/proc/base.c | 117 |
1 files changed, 112 insertions, 5 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index e8bbf6cdb437..67b6d7e2313f 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2245,6 +2245,72 @@ static const struct file_operations proc_timers_operations = { .release = seq_release_private, }; +static ssize_t timerslack_ns_write(struct file *file, const char __user *buf, + size_t count, loff_t *offset) +{ + struct inode *inode = file_inode(file); + struct task_struct *p; + u64 slack_ns; + int err; + + err = kstrtoull_from_user(buf, count, 10, &slack_ns); + if (err < 0) + return err; + + p = get_proc_task(inode); + if (!p) + return -ESRCH; + + if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) { + task_lock(p); + if (slack_ns == 0) + p->timer_slack_ns = p->default_timer_slack_ns; + else + p->timer_slack_ns = slack_ns; + task_unlock(p); + } else + count = -EPERM; + + put_task_struct(p); + + return count; +} + +static int timerslack_ns_show(struct seq_file *m, void *v) +{ + struct inode *inode = m->private; + struct task_struct *p; + int err = 0; + + p = get_proc_task(inode); + if (!p) + return -ESRCH; + + if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) { + task_lock(p); + seq_printf(m, "%llu\n", p->timer_slack_ns); + task_unlock(p); + } else + err = -EPERM; + + put_task_struct(p); + + return err; +} + +static int timerslack_ns_open(struct inode *inode, struct file *filp) +{ + return single_open(filp, timerslack_ns_show, inode); +} + +static const struct file_operations proc_pid_set_timerslack_ns_operations = { + .open = timerslack_ns_open, + .read = seq_read, + .write = timerslack_ns_write, + .llseek = seq_lseek, + .release = single_release, +}; + static int proc_pident_instantiate(struct inode *dir, struct dentry *dentry, struct task_struct *task, const void *ptr) { @@ -2795,8 +2861,8 @@ static const struct pid_entry tgid_base_stuff[] = { ONE("cgroup", S_IRUGO, proc_cgroup_show), #endif ONE("oom_score", S_IRUGO, proc_oom_score), - REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adj_operations), - REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations), + REG("oom_adj", S_IRUSR, proc_oom_adj_operations), + REG("oom_score_adj", S_IRUSR, proc_oom_score_adj_operations), #ifdef CONFIG_AUDITSYSCALL REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), REG("sessionid", S_IRUGO, proc_sessionid_operations), @@ -2822,6 +2888,7 @@ static const struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_CHECKPOINT_RESTORE REG("timers", S_IRUGO, proc_timers_operations), #endif + REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations), }; static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx) @@ -3079,6 +3146,44 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx) } /* + * proc_tid_comm_permission is a special permission function exclusively + * used for the node /proc/<pid>/task/<tid>/comm. + * It bypasses generic permission checks in the case where a task of the same + * task group attempts to access the node. + * The rational behind this is that glibc and bionic access this node for + * cross thread naming (pthread_set/getname_np(!self)). However, if + * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0, + * which locks out the cross thread naming implementation. + * This function makes sure that the node is always accessible for members of + * same thread group. + */ +static int proc_tid_comm_permission(struct inode *inode, int mask) +{ + bool is_same_tgroup; + struct task_struct *task; + + task = get_proc_task(inode); + if (!task) + return -ESRCH; + is_same_tgroup = same_thread_group(current, task); + put_task_struct(task); + + if (likely(is_same_tgroup && !(mask & MAY_EXEC))) { + /* This file (/proc/<pid>/task/<tid>/comm) can always be + * read or written by the members of the corresponding + * thread group. + */ + return 0; + } + + return generic_permission(inode, mask); +} + +static const struct inode_operations proc_tid_comm_inode_operations = { + .permission = proc_tid_comm_permission, +}; + +/* * Tasks */ static const struct pid_entry tid_base_stuff[] = { @@ -3096,7 +3201,9 @@ static const struct pid_entry tid_base_stuff[] = { #ifdef CONFIG_SCHED_DEBUG REG("sched", S_IRUGO|S_IWUSR, proc_pid_sched_operations), #endif - REG("comm", S_IRUGO|S_IWUSR, proc_pid_set_comm_operations), + NOD("comm", S_IFREG|S_IRUGO|S_IWUSR, + &proc_tid_comm_inode_operations, + &proc_pid_set_comm_operations, {}), #ifdef CONFIG_HAVE_ARCH_TRACEHOOK ONE("syscall", S_IRUSR, proc_pid_syscall), #endif @@ -3143,8 +3250,8 @@ static const struct pid_entry tid_base_stuff[] = { ONE("cgroup", S_IRUGO, proc_cgroup_show), #endif ONE("oom_score", S_IRUGO, proc_oom_score), - REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adj_operations), - REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations), + REG("oom_adj", S_IRUSR, proc_oom_adj_operations), + REG("oom_score_adj", S_IRUSR, proc_oom_score_adj_operations), #ifdef CONFIG_AUDITSYSCALL REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), REG("sessionid", S_IRUGO, proc_sessionid_operations), |