diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/proc/base.c | 69 | ||||
| -rw-r--r-- | fs/proc/inode.c | 8 | ||||
| -rw-r--r-- | fs/proc/root.c | 21 |
3 files changed, 94 insertions, 4 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 4d755fe..8173dfd 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -631,6 +631,50 @@ int proc_setattr(struct dentry *dentry, struct iattr *attr) return 0; } +/* + * May current process learn task's sched/cmdline info (for hide_pid_min=1) + * or euid/egid (for hide_pid_min=2)? + */ +static bool has_pid_permissions(struct pid_namespace *pid, + struct task_struct *task, + int hide_pid_min) +{ + if (pid->hide_pid < hide_pid_min) + return true; + if (in_group_p(pid->pid_gid)) + return true; + return ptrace_may_access(task, PTRACE_MODE_READ); +} + + +static int proc_pid_permission(struct inode *inode, int mask) +{ + struct pid_namespace *pid = inode->i_sb->s_fs_info; + struct task_struct *task; + bool has_perms; + + task = get_proc_task(inode); + has_perms = has_pid_permissions(pid, task, 1); + put_task_struct(task); + + if (!has_perms) { + if (pid->hide_pid == 2) { + /* + * Let's make getdents(), stat(), and open() + * consistent with each other. If a process + * may not stat() a file, it shouldn't be seen + * in procfs at all. + */ + return -ENOENT; + } + + return -EPERM; + } + return generic_permission(inode, mask); +} + + + static const struct inode_operations proc_def_inode_operations = { .setattr = proc_setattr, }; @@ -1615,6 +1659,7 @@ int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) struct inode *inode = dentry->d_inode; struct task_struct *task; const struct cred *cred; + struct pid_namespace *pid = dentry->d_sb->s_fs_info; generic_fillattr(inode, stat); @@ -1623,6 +1668,14 @@ int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) stat->gid = 0; task = pid_task(proc_pid(inode), PIDTYPE_PID); if (task) { + if (!has_pid_permissions(pid, task, 2)) { + rcu_read_unlock(); + /* + * This doesn't prevent learning whether PID exists, + * it only makes getattr() consistent with readdir(). + */ + return -ENOENT; + } if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) || task_dumpable(task)) { cred = __task_cred(task); @@ -3119,6 +3172,7 @@ static const struct inode_operations proc_tgid_base_inode_operations = { .lookup = proc_tgid_base_lookup, .getattr = pid_getattr, .setattr = proc_setattr, + .permission = proc_pid_permission, }; static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) @@ -3322,6 +3376,12 @@ static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldi proc_pid_instantiate, iter.task, NULL); } +static int fake_filldir(void *buf, const char *name, int namelen, + loff_t offset, u64 ino, unsigned d_type) +{ + return 0; +} + /* for the /proc/ directory itself, after non-process stuff has been done */ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir) { @@ -3329,6 +3389,7 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir) struct task_struct *reaper; struct tgid_iter iter; struct pid_namespace *ns; + filldir_t __filldir; if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET) goto out_no_task; @@ -3350,8 +3411,13 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir) for (iter = next_tgid(ns, iter); iter.task; iter.tgid += 1, iter = next_tgid(ns, iter)) { + if (has_pid_permissions(ns, iter.task, 2)) + __filldir = filldir; + else + __filldir = fake_filldir; + filp->f_pos = iter.tgid + TGID_OFFSET; - if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) { + if (proc_pid_fill_cache(filp, dirent, __filldir, iter) < 0) { put_task_struct(iter.task); goto out; } @@ -3686,6 +3752,7 @@ static const struct inode_operations proc_task_inode_operations = { .lookup = proc_task_lookup, .getattr = proc_task_getattr, .setattr = proc_setattr, + .permission = proc_pid_permission, }; static const struct file_operations proc_task_operations = { diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 27c762f..84fd323 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -106,6 +106,14 @@ void __init proc_init_inodecache(void) static int proc_show_options(struct seq_file *seq, struct dentry *root) { + struct super_block *sb = root->d_sb; + struct pid_namespace *pid = sb->s_fs_info; + + if (pid->pid_gid) + seq_printf(seq, ",gid=%lu", (unsigned long)pid->pid_gid); + if (pid->hide_pid != 0) + seq_printf(seq, ",hidepid=%u", pid->hide_pid); + return 0; } diff --git a/fs/proc/root.c b/fs/proc/root.c index 6a8ac1d..46a15d8 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -38,10 +38,12 @@ static int proc_set_super(struct super_block *sb, void *data) } enum { - Opt_err, + Opt_gid, Opt_hidepid, Opt_err, }; static const match_table_t tokens = { + {Opt_hidepid, "hidepid=%u"}, + {Opt_gid, "gid=%u"}, {Opt_err, NULL}, }; @@ -49,8 +51,7 @@ static int proc_parse_options(char *options, struct pid_namespace *pid) { char *p; substring_t args[MAX_OPT_ARGS]; - - pr_debug("proc: options = %s\n", options); + int option; if (!options) return 1; @@ -63,6 +64,20 @@ static int proc_parse_options(char *options, struct pid_namespace *pid) args[0].to = args[0].from = 0; token = match_token(p, tokens, args); switch (token) { + case Opt_gid: + if (match_int(&args[0], &option)) + return 0; + pid->pid_gid = option; + break; + case Opt_hidepid: + if (match_int(&args[0], &option)) + return 0; + if (option < 0 || option > 2) { + pr_err("proc: hidepid value must be between 0 and 2.\n"); + return 0; + } + pid->hide_pid = option; + break; default: pr_err("proc: unrecognized mount option \"%s\" " "or missing value\n", p); |