5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paulo Alcantara <pc@xxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxxxx
Reported-by: Robert Morris <rtm@xxxxxxxxxxxxx>
Signed-off-by: Paulo Alcantara (SUSE) <pc@xxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/cifs/smb2ops.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index d8ce079ba9091..7c2ecbb17f542 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2926,6 +2926,8 @@ 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);
--
2.42.0
