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Commit d99376b7 authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Greg Kroah-Hartman
Browse files

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: 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>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent ab5813bb

fs/cifs/smb2ops.c

+2 −0
Original line number Diff line number Diff line
@@ -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);