This series of patch tries to implement the get_dfs_refer operation for SMB2+. In SMB2+, DFS resolving is now done through an FSCTL (patch #3). The relevant Microsoft specifications for this are: MS-SMB2: 3.2.4.20 Application Requests an IO Control Code Operation MS-SMB2: 3.2.4.20.3 Application Requests DFS Referral Information MS-SMB2: 3.2.5.14 Receiving an SMB2 IOCTL Response MS-SMB2: 3.2.5.14.4 Handling a DFS Referral Information Response MS-DFSC: 2.2 Message Syntax (but really the whole document is useful) The DFS response payload however is identical. Patch #1 moves the DFS response parsing out of SMB1 code and makes it work on any version of SMB. DFS code has 2 "main" entry points: initial mounting and automount (when a DFS link is accessed/traversed). When automounting, cifs.ko calls build_path_from_dentry() which only makes treename-prefixed paths when the tcon has the SMB_IN_DFS_SHARE. This flag is checked in tcon->Flags which is never touched by SMB2 code as it sets tcon->share_flags on connexion. * CIFS requires to prefix all pathnames with the treename prefix when connected to a DFS server, so the current build_path_from_dentry() makes sense for CIFS. * For SMB2+ it seems only the Create request requires the treename prefix. Simply making the function check for both CIFS SMB2+ flag for DFS to add a prefix does not work as the server has different expectations about which packet can have/require a DFS pathname. Patch #2 adds build_path_from_dentry_optional_prefix() with an extra bool arg to decide to prefix or not. The automount code path always ask for it. Patch #5 modifies SMB2_open() to add the treename prefix to the given path if the server requires it. As part of the mouting process a IPC tcon is made (I suspect we don't need it anymore in SMB3). This tcon doesn't respect the signing requirement. This is fixed by patch #4. Finally the SMB2+ implementation of the get_dfs_referral operation is added in all supported SMB versions in patch #6. I've sucessfuly tested this against a Windows Server 2016 DFS setup. Samba requires a patch as currently it only accepts DFS referrals requests on an IPC connexion, which is in violation of the spec. A patch was sent on samba-technical: https://lists.samba.org/archive/samba-technical/2017-February/118859.html Changes since v1: * The fsctl is made on the first available tcon to the server, which is allowed by the spec. This way we avoid hardcoding additional rules in SMB2_ioctl(). * add signing flag in smb2 header if required * no copy/pasting, the DFS parsing code is now generic and works for both SMB versions * add treename prefix in SMB2_open() when required Aurelien Aptel (6): CIFS: move DFS response parsing out of SMB1 code CIFS: add build_path_from_dentry_optional_prefix() CIFS: implement get_dfs_refer for SMB2+ CIFS: set signing flag in SMB2+ TreeConnect if needed CIFS: use DFS pathnames in SMB2+ Create requests CIFS: enable get_dfs_refer for SMB2+ fs/cifs/cifs_dfs_ref.c | 4 +- fs/cifs/cifspdu.h | 16 ++++--- fs/cifs/cifsproto.h | 7 +++ fs/cifs/cifssmb.c | 119 +++---------------------------------------------- fs/cifs/dir.c | 13 +++++- fs/cifs/misc.c | 105 +++++++++++++++++++++++++++++++++++++++++++ fs/cifs/smb2ops.c | 76 +++++++++++++++++++++++++++++++ fs/cifs/smb2pdu.c | 97 ++++++++++++++++++++++++++++++++-------- fs/cifs/smb2pdu.h | 8 ++++ 9 files changed, 305 insertions(+), 140 deletions(-) -- 2.10.2 -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
