[PATCH v2] proc: proc_pid_ns takes super_block as an argument
Eric W. Biederman
ebiederm at xmission.com
Mon May 18 12:08:57 UTC 2020
Alexey Gladkov <gladkov.alexey at gmail.com> 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/c3461e26-1407-2262-c709-dac0df3da2d0@i-love.sakura.ne.jp/
> Reported-by: syzbot+c1af344512918c61362c at syzkaller.appspotmail.com
> Signed-off-by: Alexey Gladkov <gladkov.alexey at gmail.com>
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.
And can you please compile test this?
There is a very silly typo in proc that keeps this from compiling.
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)) {
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