proc: reject "." and ".." as filenames

Various subsystems can create files and directories in /proc with names
directly controlled by userspace.

Which means "/", "." and ".." are no-no.

"/" split is already taken care of, do the other 2 prohibited names.

Link: http://lkml.kernel.org/r/20180310001223.GB12443@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Florian Westphal <fw@strlen.de>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan 2018-04-10 16:32:11 -07:00 committed by Linus Torvalds
parent 5de3d401b7
commit b77d70db65

View file

@ -366,6 +366,14 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
WARN(1, "name len %u\n", qstr.len);
return NULL;
}
if (qstr.len == 1 && fn[0] == '.') {
WARN(1, "name '.'\n");
return NULL;
}
if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
WARN(1, "name '..'\n");
return NULL;
}
if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
WARN(1, "create '/proc/%s' by hand\n", qstr.name);
return NULL;