cifs: do not allow creating sockets in SMB1

Message ID 20180419000226.26479-2-lsahlber@redhat.com
State New
Headers show
Series
  • cifs: fix kernel NULL deref
Related show

Commit Message

Ronnie Sahlberg April 19, 2018, 12:02 a.m.
RHBZ: 1453123

Since at least the 3.10 kernel and likely a lot earlier we have
not been able to create unix domain sockets in a cifs share.
Trying to create a socket, for example using the af_unix command from
xfstests will cause :
BUG: unable to handle kernel NULL pointer dereference at 00000000
00000040

Since no one uses or depends on being able to create unix domains sockets
on a cifs share the easiest fix to stop this vulnerability is to simply
disallow creation of such sockets.

Reported-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/dir.c | 3 +++
 1 file changed, 3 insertions(+)

Patch

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 81ba6e0d88d8..2ba68fcb6df3 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -637,6 +637,9 @@  int cifs_mknod(struct inode *inode, struct dentry *direntry, umode_t mode,
 	struct win_dev *pdev;
 	struct kvec iov[2];
 
+	if (S_ISSOCK(mode))
+		return -EINVAL;
+
 	if (!old_valid_dev(device_number))
 		return -EINVAL;