From b77d70db659ad3aa662c80cff4475e773a531fbe Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Tue, 10 Apr 2018 16:32:11 -0700 Subject: 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 Acked-by: Florian Westphal Cc: Eric Dumazet Cc: Cong Wang Cc: Pavel Machek Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/generic.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'fs') diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 800247a256c9..5dad2e89007b 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -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; -- cgit v1.2.3