From d99376b70247394b39307051f994060a085a417e Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Tue, 5 Dec 2023 21:49:29 -0300 Subject: smb: client: fix potential NULL deref in parse_dfs_referrals() [ Upstream commit 92414333eb375ed64f4ae92d34d579e826936480 ] If server returned no data for FSCTL_DFS_GET_REFERRALS, @dfs_rsp will remain NULL and then parse_dfs_referrals() will dereference it. Fix this by returning -EIO when no output data is returned. Besides, we can't fix it in SMB2_ioctl() as some FSCTLs are allowed to return no data as per MS-SMB2 2.2.32. Fixes: 9d49640a21bf ("CIFS: implement get_dfs_refer for SMB2+") Cc: stable@vger.kernel.org Reported-by: Robert Morris Signed-off-by: Paulo Alcantara (SUSE) Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/cifs/smb2ops.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index ad9b207432e1..5fea15a5f341 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -2498,6 +2498,8 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses, (char **)&dfs_rsp, &dfs_rsp_size); } while (rc == -EAGAIN); + if (!rc && !dfs_rsp) + rc = -EIO; if (rc) { if ((rc != -ENOENT) && (rc != -EOPNOTSUPP)) cifs_tcon_dbg(VFS, "ioctl error in %s rc=%d\n", __func__, rc); -- cgit v1.2.3