diff options
| author | David Howells <dhowells@redhat.com> | 2020-01-26 01:02:53 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-29 16:45:24 +0100 |
| commit | 2d00fec60c8d5c19b0c85936b47ec50ac7917bc5 (patch) | |
| tree | 96f5977c6b2c37acdaf6205117a8bba54dfced37 | |
| parent | b29d143a690a660b27e7e84c01dd541d38fe9372 (diff) | |
afs: Fix characters allowed into cell names
commit a45ea48e2bcd92c1f678b794f488ca0bda9835b8 upstream.
The afs filesystem needs to prohibit certain characters from cell names,
such as '/', as these are used to form filenames in procfs, leading to
the following warning being generated:
WARNING: CPU: 0 PID: 3489 at fs/proc/generic.c:178
Fix afs_alloc_cell() to disallow nonprintable characters, '/', '@' and
names that begin with a dot.
Remove the check for "@cell" as that is then redundant.
This can be tested by running:
echo add foo/.bar 1.2.3.4 >/proc/fs/afs/cells
Note that we will also need to deal with:
- Names ending in ".invalid" shouldn't be passed to the DNS.
- Names that contain non-valid domainname chars shouldn't be passed to
the DNS.
- DNS replies that say "your-dns-needs-immediate-attention.<gTLD>" and
replies containing A records that say 127.0.53.53 should be
considered invalid.
[https://www.icann.org/en/system/files/files/name-collision-mitigation-01aug14-en.pdf]
but these need to be dealt with by the kafs-client DNS program rather
than the kernel.
Reported-by: syzbot+b904ba7c947a37b4b291@syzkaller.appspotmail.com
Cc: stable@kernel.org
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/afs/cell.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/afs/cell.c b/fs/afs/cell.c index fd5133e26a38..78ba5f932287 100644 --- a/fs/afs/cell.c +++ b/fs/afs/cell.c @@ -134,8 +134,17 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net, _leave(" = -ENAMETOOLONG"); return ERR_PTR(-ENAMETOOLONG); } - if (namelen == 5 && memcmp(name, "@cell", 5) == 0) + + /* Prohibit cell names that contain unprintable chars, '/' and '@' or + * that begin with a dot. This also precludes "@cell". + */ + if (name[0] == '.') return ERR_PTR(-EINVAL); + for (i = 0; i < namelen; i++) { + char ch = name[i]; + if (!isprint(ch) || ch == '/' || ch == '@') + return ERR_PTR(-EINVAL); + } _enter("%*.*s,%s", namelen, namelen, name, addresses); |