lkml.org 
[lkml]   [2018]   [Apr]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH?] reiserfs: prevent panic: don't allow %-char in journal dev. name
Date
From: Randy Dunlap <rdunlap@infradead.org>

If the reiserfs mount option's journal name contains a '%' character,
it can lead to a WARN_ONCE() in lib/vsprintf.c::format_decode(),
saying: "Please remove unsupported %/ in format string."
That's OK until panic_on_warn is set, at which point it's dead, Jim.

To placate this situation, check the journal name string for a '%'
character and return an error if one is found. Also print a warning
(one that won't panic the kernel) about the invalid journal name (e.g.):

reiserfs: journal device name is invalid: %/file0

(In this example, the caller app specified the journal device name as
"%/file0".)

Fixes: https://syzkaller.appspot.com/bug?id=0627d4551fdc39bf1ef5d82cd9eef587047f7718

Reported-by: syzbot+6bd77b88c1977c03f584@syzkaller.appspotmail.com
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: stable@vger.kernel.org # many kernel versions
Cc: reiserfs-devel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Andrew Morton <akpm@linuxfoundation.org>
---
fs/reiserfs/super.c | 11 +++++++++++
1 file changed, 11 insertions(+)

--- lnx-416.orig/fs/reiserfs/super.c
+++ lnx-416/fs/reiserfs/super.c
@@ -1239,6 +1239,8 @@ static int reiserfs_parse_options(struct
}

if (c == 'j') {
+ char *badfmt; // jdev_name (arg) cannot contain '%'
+
if (arg && *arg && jdev_name) {
/* Hm, already assigned? */
if (*jdev_name) {
@@ -1248,6 +1250,15 @@ static int reiserfs_parse_options(struct
"be %s", *jdev_name);
return 0;
}
+
+ badfmt = strchr(arg, '%');
+ if (badfmt) {
+ printk(KERN_WARNING "reiserfs: "
+ "journal device name "
+ "is invalid: %s",
+ arg);
+ return 0;
+ }
*jdev_name = arg;
}
}
\
 
 \ /
  Last update: 2018-04-05 03:26    [W:0.094 / U:3.788 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site