Commit 92414333 authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French
Browse files

smb: client: fix potential NULL deref in parse_dfs_referrals() 



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: 9d49640a ("CIFS: implement get_dfs_refer for SMB2+")
Cc: stable@vger.kernel.org
Reported-by: default avatarRobert Morris <rtm@csail.mit.edu>
Signed-off-by: default avatarPaulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent c54fc3a4

fs/smb/client/smb2ops.c

+2 −0
Original line number Diff line number Diff line
@@ -2836,6 +2836,8 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses, 
		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);