From b9a74cde94957d82003fb9f7ab4777938ca851cd Mon Sep 17 00:00:00 2001 From: Ross Lagerwall Date: Tue, 8 Jan 2019 18:30:57 +0000 Subject: cifs: Fix potential OOB access of lock element array If maxBuf is small but non-zero, it could result in a zero sized lock element array which we would then try and access OOB. Signed-off-by: Ross Lagerwall Signed-off-by: Steve French CC: Stable --- fs/cifs/smb2file.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/cifs/smb2file.c') diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c index eff01ed6db0a..b204e84b87fb 100644 --- a/fs/cifs/smb2file.c +++ b/fs/cifs/smb2file.c @@ -122,10 +122,10 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, /* * Accessing maxBuf is racy with cifs_reconnect - need to store value - * and check it for zero before using. + * and check it before using. */ max_buf = tcon->ses->server->maxBuf; - if (!max_buf) + if (max_buf < sizeof(struct smb2_lock_element)) return -EINVAL; BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE); -- cgit v1.2.3-59-g8ed1b