Commit 488e5bc4 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds

proc: proper pidns handling for /proc/self

Currently if you access a /proc that is not mounted with your processes
current pid namespace /proc/self will point at a completely random task.

This patch fixes /proc/self to point to the current process if it is
available in the particular mount of /proc or to return -ENOENT if the
current process is not visible.
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent df5f8314
...@@ -2101,15 +2101,23 @@ static const struct file_operations proc_coredump_filter_operations = { ...@@ -2101,15 +2101,23 @@ static const struct file_operations proc_coredump_filter_operations = {
static int proc_self_readlink(struct dentry *dentry, char __user *buffer, static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
int buflen) int buflen)
{ {
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
pid_t tgid = task_tgid_nr_ns(current, ns);
char tmp[PROC_NUMBUF]; char tmp[PROC_NUMBUF];
sprintf(tmp, "%d", task_tgid_vnr(current)); if (!tgid)
return -ENOENT;
sprintf(tmp, "%d", tgid);
return vfs_readlink(dentry,buffer,buflen,tmp); return vfs_readlink(dentry,buffer,buflen,tmp);
} }
static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd) static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
{ {
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
pid_t tgid = task_tgid_nr_ns(current, ns);
char tmp[PROC_NUMBUF]; char tmp[PROC_NUMBUF];
sprintf(tmp, "%d", task_tgid_vnr(current)); if (!tgid)
return ERR_PTR(-ENOENT);
sprintf(tmp, "%d", task_tgid_nr_ns(current, ns));
return ERR_PTR(vfs_follow_link(nd,tmp)); return ERR_PTR(vfs_follow_link(nd,tmp));
} }
......
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