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From: Alexey Dobriyan <adobriyan@gmail.com>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, eric.dumazet@gmail.com,
	xiyou.wangcong@gmail.com, fw@strlen.de
Subject: [PATCH] proc: reject "." and ".." as filenames
Date: Sat, 10 Mar 2018 03:12:23 +0300
Message-ID: <20180310001223.GB12443@avx2> (raw)

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.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 fs/proc/generic.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- 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;

             reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-10  0:12 Alexey Dobriyan [this message]
2018-03-10  0:19 ` Florian Westphal
2018-03-11 21:30 ` Pavel Machek
2018-03-11 21:35   ` Alexey Dobriyan
2018-03-11 21:41     ` Pavel Machek
2018-03-12 23:00 ` Andrew Morton
2018-03-13  7:20   ` Alexey Dobriyan

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