6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paulo Alcantara pc@manguebit.com
commit 92414333eb375ed64f4ae92d34d579e826936480 upstream.
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 rtm@csail.mit.edu Signed-off-by: Paulo Alcantara (SUSE) pc@manguebit.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/smb/client/smb2ops.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -2834,6 +2834,8 @@ smb2_get_dfs_refer(const unsigned int xi usleep_range(512, 2048); } while (++retry_count < 5);
+ if (!rc && !dfs_rsp) + rc = -EIO; if (rc) { if (!is_retryable_error(rc) && rc != -ENOENT && rc != -EOPNOTSUPP) cifs_tcon_dbg(VFS, "%s: ioctl error: rc=%d\n", __func__, rc);