On Mon, May 18, 2020 at 07:08:57AM -0500, Eric W. Biederman wrote:
> Alexey Gladkov <[email protected]> writes:
>
> > The proc_pid_ns() can be used for both inode and dentry. To avoid making
> > two identical functions, change the argument type of the proc_pid_ns().
> >
> > Link:
> > https://lore.kernel.org/lkml/[email protected]/
> > Reported-by: [email protected]
> > Signed-off-by: Alexey Gladkov <[email protected]>
>
> So overall this looks good.
>
> However, the description leaves a little bit to be desired as it does
> not describe why it is bad to use dentry->d_sb. A fixes tag would be
> nice if for no other reason than to help anyone who decides to backport
> this.
OK. I will add it.
> And can you please compile test this?
>
> There is a very silly typo in proc that keeps this from compiling.
I compiled the kernel with this patch and ran the kernel, but accidentally
did not check children_seq_show(). Sorry.
> Thank you,
> Eric
>
> > ---
> > fs/locks.c | 4 ++--
> > fs/proc/array.c | 2 +-
> > fs/proc/base.c | 10 +++++-----
> > fs/proc/self.c | 2 +-
> > fs/proc/thread_self.c | 2 +-
> > include/linux/proc_fs.h | 4 ++--
> > kernel/fork.c | 2 +-
> > net/ipv6/ip6_flowlabel.c | 2 +-
> > security/tomoyo/realpath.c | 2 +-
> > 9 files changed, 15 insertions(+), 15 deletions(-)
> >
> > diff --git a/fs/locks.c b/fs/locks.c
> > index 399c5dbb72c4..ab702d6efb55 100644
> > --- a/fs/locks.c
> > +++ b/fs/locks.c
> > @@ -2823,7 +2823,7 @@ static void lock_get_status(struct seq_file *f,
> > struct file_lock *fl,
> > {
> > struct inode *inode = NULL;
> > unsigned int fl_pid;
> > - struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file));
> > + struct pid_namespace *proc_pidns =
> > proc_pid_ns(file_inode(f->file)->i_sb);
> >
> > fl_pid = locks_translate_pid(fl, proc_pidns);
> > /*
> > @@ -2901,7 +2901,7 @@ static int locks_show(struct seq_file *f, void *v)
> > {
> > struct locks_iterator *iter = f->private;
> > struct file_lock *fl, *bfl;
> > - struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file));
> > + struct pid_namespace *proc_pidns =
> > proc_pid_ns(file_inode(f->file)->i_sb);
> >
> > fl = hlist_entry(v, struct file_lock, fl_link);
> >
> > diff --git a/fs/proc/array.c b/fs/proc/array.c
> > index 8e16f14bb05a..a4d4763731e0 100644
> > --- a/fs/proc/array.c
> > +++ b/fs/proc/array.c
> > @@ -728,7 +728,7 @@ static int children_seq_show(struct seq_file *seq, void
> > *v)
> > {
> > struct inode *inode = file_inode(seq->file);
> >
> > - seq_printf(seq, "%d ", pid_nr_ns(v, proc_pid_ns(inode)));
> > + seq_printf(seq, "%d ", pid_nr_ns(v, proc_pid_ns(inode)->i_sb));
> > return 0;
> > }
> >
> > diff --git a/fs/proc/base.c b/fs/proc/base.c
> > index 5a307b3bb2d1..30c9fceca0b7 100644
> > --- a/fs/proc/base.c
> > +++ b/fs/proc/base.c
> > @@ -754,7 +754,7 @@ static const struct inode_operations
> > proc_def_inode_operations = {
> > static int proc_single_show(struct seq_file *m, void *v)
> > {
> > struct inode *inode = m->private;
> > - struct pid_namespace *ns = proc_pid_ns(inode);
> > + struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
> > struct pid *pid = proc_pid(inode);
> > struct task_struct *task;
> > int ret;
> > @@ -1423,7 +1423,7 @@ 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 = proc_pid_ns(inode);
> > + struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
> > struct task_struct *p;
> >
> > p = get_proc_task(inode);
> > @@ -2466,7 +2466,7 @@ static int proc_timers_open(struct inode *inode,
> > struct file *file)
> > return -ENOMEM;
> >
> > tp->pid = proc_pid(inode);
> > - tp->ns = proc_pid_ns(inode);
> > + tp->ns = proc_pid_ns(inode->i_sb);
> > return 0;
> > }
> >
> > @@ -3377,7 +3377,7 @@ int proc_pid_readdir(struct file *file, struct
> > dir_context *ctx)
> > {
> > struct tgid_iter iter;
> > struct proc_fs_info *fs_info = proc_sb_info(file_inode(file)->i_sb);
> > - struct pid_namespace *ns = proc_pid_ns(file_inode(file));
> > + struct pid_namespace *ns = proc_pid_ns(file_inode(file)->i_sb);
> > loff_t pos = ctx->pos;
> >
> > if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
> > @@ -3730,7 +3730,7 @@ static int proc_task_readdir(struct file *file,
> > struct dir_context *ctx)
> > /* f_version caches the tgid value that the last readdir call couldn't
> > * return. lseek aka telldir automagically resets f_version to 0.
> > */
> > - ns = proc_pid_ns(inode);
> > + ns = proc_pid_ns(inode->i_sb);
> > tid = (int)file->f_version;
> > file->f_version = 0;
> > for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
> > diff --git a/fs/proc/self.c b/fs/proc/self.c
> > index 309301ac0136..ca5158fa561c 100644
> > --- a/fs/proc/self.c
> > +++ b/fs/proc/self.c
> > @@ -12,7 +12,7 @@ static const char *proc_self_get_link(struct dentry
> > *dentry,
> > struct inode *inode,
> > struct delayed_call *done)
> > {
> > - struct pid_namespace *ns = proc_pid_ns(inode);
> > + struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
> > pid_t tgid = task_tgid_nr_ns(current, ns);
> > char *name;
> >
> > diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c
> > index 2493cbbdfa6f..ac284f409568 100644
> > --- a/fs/proc/thread_self.c
> > +++ b/fs/proc/thread_self.c
> > @@ -12,7 +12,7 @@ static const char *proc_thread_self_get_link(struct
> > dentry *dentry,
> > struct inode *inode,
> > struct delayed_call *done)
> > {
> > - struct pid_namespace *ns = proc_pid_ns(inode);
> > + struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
> > pid_t tgid = task_tgid_nr_ns(current, ns);
> > pid_t pid = task_pid_nr_ns(current, ns);
> > char *name;
> > diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
> > index 2cb424e6f36a..6ec524d8842c 100644
> > --- a/include/linux/proc_fs.h
> > +++ b/include/linux/proc_fs.h
> > @@ -202,9 +202,9 @@ int open_related_ns(struct ns_common *ns,
> > struct ns_common *(*get_ns)(struct ns_common *ns));
> >
> > /* get the associated pid namespace for a file in procfs */
> > -static inline struct pid_namespace *proc_pid_ns(const struct inode *inode)
> > +static inline struct pid_namespace *proc_pid_ns(struct super_block *sb)
> > {
> > - return proc_sb_info(inode->i_sb)->pid_ns;
> > + return proc_sb_info(sb)->pid_ns;
> > }
> >
> > #endif /* _LINUX_PROC_FS_H */
> > diff --git a/kernel/fork.c b/kernel/fork.c
> > index 4385f3d639f2..e7bdaccad942 100644
> > --- a/kernel/fork.c
> > +++ b/kernel/fork.c
> > @@ -1745,7 +1745,7 @@ static void pidfd_show_fdinfo(struct seq_file *m,
> > struct file *f)
> > pid_t nr = -1;
> >
> > if (likely(pid_has_task(pid, PIDTYPE_PID))) {
> > - ns = proc_pid_ns(file_inode(m->file));
> > + ns = proc_pid_ns(file_inode(m->file)->i_sb);
> > nr = pid_nr_ns(pid, ns);
> > }
> >
> > diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
> > index d64b83e85642..ce4fbba4acce 100644
> > --- a/net/ipv6/ip6_flowlabel.c
> > +++ b/net/ipv6/ip6_flowlabel.c
> > @@ -779,7 +779,7 @@ static void *ip6fl_seq_start(struct seq_file *seq,
> > loff_t *pos)
> > {
> > struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
> >
> > - state->pid_ns = proc_pid_ns(file_inode(seq->file));
> > + state->pid_ns = proc_pid_ns(file_inode(seq->file)->i_sb);
> >
> > rcu_read_lock_bh();
> > return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
> > diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c
> > index 08b096e2f7e3..df4798980416 100644
> > --- a/security/tomoyo/realpath.c
> > +++ b/security/tomoyo/realpath.c
> > @@ -162,7 +162,7 @@ static char *tomoyo_get_local_path(struct dentry
> > *dentry, char * const buffer,
> > if (sb->s_magic == PROC_SUPER_MAGIC && *pos == '/') {
> > char *ep;
> > const pid_t pid = (pid_t) simple_strtoul(pos + 1, &ep, 10);
> > - struct pid_namespace *proc_pidns = proc_pid_ns(d_inode(dentry));
> > + struct pid_namespace *proc_pidns = proc_pid_ns(sb);
> >
> > if (*ep == '/' && pid && pid ==
> > task_tgid_nr_ns(current, proc_pidns)) {
>
--
Rgrds, legion
