The branch, v4-7-test has been updated
       via  53643ac vfs_gpfs: handle EACCES when fetching DOS attributes from 
xattr
       via  07b678b s3/smbd: handle EACCES when fetching DOS attributes from 
xattr
       via  a64088b s3/smbd: handling of failed DOS attributes reading
      from  cb38898 python: Fix incorrect kdc.conf parameter name in kerberos.py

https://git.samba.org/?p=samba.git;a=shortlog;h=v4-7-test


- Log -----------------------------------------------------------------
commit 53643ac0eb2391ddebab11916f010d28039eb4ba
Author: Ralph Boehme <s...@samba.org>
Date:   Thu Jun 8 19:18:36 2017 +0200

    vfs_gpfs: handle EACCES when fetching DOS attributes from xattr
    
    When trying to fetch the DOS attributes via gpfswrap_get_winattrs_path()
    if the filesystem doesn't grant READ_ATTR to the file the function fails
    with EACCESS.
    
    But according to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to an
    Existing File" FILE_LIST_DIRECTORY on a directory implies
    FILE_READ_ATTRIBUTES for directory entries.
    
    So if the user can open the parent directory for reading this implies
    FILE_LIST_DIRECTORY and we can safely call gpfswrap_get_winattrs_path()
    with DAC_OVERRIDE_CAPABILITY.
    
    Bug: https://bugzilla.samba.org/show_bug.cgi?id=12944
    
    Signed-off-by: Ralph Boehme <s...@samba.org>
    Reviewed-by: Christof Schmitt <c...@samba.org>
    
    Autobuild-User(master): Ralph Böhme <s...@samba.org>
    Autobuild-Date(master): Wed Aug  9 01:21:14 CEST 2017 on sn-devel-144
    
    (cherry picked from commit 62d73f5b936550d623ef4f31c7438ac3c90105b9)
    
    Autobuild-User(v4-7-test): Karolin Seeger <ksee...@samba.org>
    Autobuild-Date(v4-7-test): Fri Aug 11 14:48:10 CEST 2017 on sn-devel-144

commit 07b678b377194d4e6b41e4d4e1609c3c55367cc0
Author: Ralph Boehme <s...@samba.org>
Date:   Thu Jun 8 19:10:20 2017 +0200

    s3/smbd: handle EACCES when fetching DOS attributes from xattr
    
    When trying to fetch the DOS attributes xattr via SMB_VFS_GETXATTR() if
    the filesystem doesn't grant read access to the file the xattr read
    request fails with EACCESS.
    
    But according to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to an
    Existing File" FILE_LIST_DIRECTORY on a directory implies
    FILE_READ_ATTRIBUTES for directory entries.
    
    So if the user can open the parent directory for reading this implies
    FILE_LIST_DIRECTORY and we can safely call SMB_VFS_GETXATTR() as root,
    ensuring we can read the DOS attributes xattr.
    
    Bug: https://bugzilla.samba.org/show_bug.cgi?id=12944
    
    Signed-off-by: Ralph Boehme <s...@samba.org>
    Reviewed-by: Christof Schmitt <c...@samba.org>
    (cherry picked from commit c54fcb7cbd0de244eed4134e877da6e9c16e7aab)

commit a64088bdf223d408da4ad7912d5ea9c779ced34c
Author: Ralph Boehme <s...@samba.org>
Date:   Thu Jun 8 19:05:48 2017 +0200

    s3/smbd: handling of failed DOS attributes reading
    
    Only fall back to using UNIX modes if we get NOT_IMPLEMENTED. This is
    exactly what we already do when setting DOS attributes.
    
    Bug: https://bugzilla.samba.org/show_bug.cgi?id=12944
    
    Signed-off-by: Ralph Boehme <s...@samba.org>
    Reviewed-by: Christof Schmitt <c...@samba.org>
    (cherry picked from commit 9de1411d9e7c7ac3da544345d4dea7fd73dff01b)

-----------------------------------------------------------------------

Summary of changes:
 source3/modules/vfs_gpfs.c | 69 +++++++++++++++++++++++++++++++++++++++++++++-
 source3/smbd/dosmode.c     | 43 ++++++++++++++++++++++++++++-
 2 files changed, 110 insertions(+), 2 deletions(-)


Changeset truncated at 500 lines:

diff --git a/source3/modules/vfs_gpfs.c b/source3/modules/vfs_gpfs.c
index a552cdd..b2c9244 100644
--- a/source3/modules/vfs_gpfs.c
+++ b/source3/modules/vfs_gpfs.c
@@ -1537,6 +1537,47 @@ static unsigned int 
vfs_gpfs_dosmode_to_winattrs(uint32_t dosmode)
        return winattrs;
 }
 
+static int get_dos_attr_with_capability(struct smb_filename *smb_fname,
+                                       struct gpfs_winattr *attr)
+{
+       int saved_errno = 0;
+       int ret;
+
+       /*
+        * According to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to an
+        * Existing File" FILE_LIST_DIRECTORY on a directory implies
+        * FILE_READ_ATTRIBUTES for directory entries. Being able to stat() a
+        * file implies FILE_LIST_DIRECTORY for the directory containing the
+        * file.
+        */
+
+       if (!VALID_STAT(smb_fname->st)) {
+               /*
+                * Safety net: dos_mode() already checks this, but as we set
+                * DAC_OVERRIDE_CAPABILITY based on this, add an additional
+                * layer of defense.
+                */
+               DBG_ERR("Rejecting DAC override, invalid stat [%s]\n",
+                       smb_fname_str_dbg(smb_fname));
+               errno = EACCES;
+               return -1;
+       }
+
+       set_effective_capability(DAC_OVERRIDE_CAPABILITY);
+
+       ret = gpfswrap_get_winattrs_path(smb_fname->base_name, attr);
+       if (ret == -1) {
+               saved_errno = errno;
+       }
+
+       drop_effective_capability(DAC_OVERRIDE_CAPABILITY);
+
+       if (saved_errno != 0) {
+               errno = saved_errno;
+       }
+       return ret;
+}
+
 static NTSTATUS vfs_gpfs_get_dos_attributes(struct vfs_handle_struct *handle,
                                            struct smb_filename *smb_fname,
                                            uint32_t *dosmode)
@@ -1559,7 +1600,9 @@ static NTSTATUS vfs_gpfs_get_dos_attributes(struct 
vfs_handle_struct *handle,
                return SMB_VFS_NEXT_GET_DOS_ATTRIBUTES(handle, smb_fname,
                                                       dosmode);
        }
-
+       if (ret == -1 && errno == EACCES) {
+               ret = get_dos_attr_with_capability(smb_fname, &attrs);
+       }
        if (ret == -1) {
                DBG_WARNING("Getting winattrs failed for %s: %s\n",
                            smb_fname->base_name, strerror(errno));
@@ -1595,6 +1638,30 @@ static NTSTATUS vfs_gpfs_fget_dos_attributes(struct 
vfs_handle_struct *handle,
                return SMB_VFS_NEXT_FGET_DOS_ATTRIBUTES(handle, fsp, dosmode);
        }
 
+       if (ret == -1 && errno == EACCES) {
+               int saved_errno = 0;
+
+               /*
+                * According to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to
+                * an Existing File" FILE_LIST_DIRECTORY on a directory implies
+                * FILE_READ_ATTRIBUTES for directory entries. Being able to
+                * open a file implies FILE_LIST_DIRECTORY.
+                */
+
+               set_effective_capability(DAC_OVERRIDE_CAPABILITY);
+
+               ret = gpfswrap_get_winattrs(fsp->fh->fd, &attrs);
+               if (ret == -1) {
+                       saved_errno = errno;
+               }
+
+               drop_effective_capability(DAC_OVERRIDE_CAPABILITY);
+
+               if (saved_errno != 0) {
+                       errno = saved_errno;
+               }
+       }
+
        if (ret == -1) {
                DBG_WARNING("Getting winattrs failed for %s: %s\n",
                            fsp->fsp_name->base_name, strerror(errno));
diff --git a/source3/smbd/dosmode.c b/source3/smbd/dosmode.c
index 0ee6894..3181f2e 100644
--- a/source3/smbd/dosmode.c
+++ b/source3/smbd/dosmode.c
@@ -281,6 +281,42 @@ NTSTATUS get_ea_dos_attribute(connection_struct *conn,
        sizeret = SMB_VFS_GETXATTR(conn, smb_fname,
                                   SAMBA_XATTR_DOS_ATTRIB, attrstr,
                                   sizeof(attrstr));
+       if (sizeret == -1 && errno == EACCES) {
+               int saved_errno = 0;
+
+               /*
+                * According to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to
+                * an Existing File" FILE_LIST_DIRECTORY on a directory implies
+                * FILE_READ_ATTRIBUTES for directory entries. Being able to
+                * stat() a file implies FILE_LIST_DIRECTORY for the directory
+                * containing the file.
+                */
+
+               if (!VALID_STAT(smb_fname->st)) {
+                       /*
+                        * Safety net: dos_mode() already checks this, but as we
+                        * become root based on this, add an additional layer of
+                        * defense.
+                        */
+                       DBG_ERR("Rejecting root override, invalid stat [%s]\n",
+                               smb_fname_str_dbg(smb_fname));
+                       return NT_STATUS_ACCESS_DENIED;
+               }
+
+               become_root();
+               sizeret = SMB_VFS_GETXATTR(conn, smb_fname,
+                                          SAMBA_XATTR_DOS_ATTRIB,
+                                          attrstr,
+                                          sizeof(attrstr));
+               if (sizeret == -1) {
+                       saved_errno = errno;
+               }
+               unbecome_root();
+
+               if (saved_errno != 0) {
+                       errno = saved_errno;
+               }
+       }
        if (sizeret == -1) {
                DBG_INFO("Cannot get attribute "
                         "from EA on file %s: Error = %s\n",
@@ -622,7 +658,12 @@ uint32_t dos_mode(connection_struct *conn, struct 
smb_filename *smb_fname)
        /* Get the DOS attributes via the VFS if we can */
        status = SMB_VFS_GET_DOS_ATTRIBUTES(conn, smb_fname, &result);
        if (!NT_STATUS_IS_OK(status)) {
-               result |= dos_mode_from_sbuf(conn, smb_fname);
+               /*
+                * Only fall back to using UNIX modes if we get NOT_IMPLEMENTED.
+                */
+               if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_IMPLEMENTED)) {
+                       result |= dos_mode_from_sbuf(conn, smb_fname);
+               }
        }
 
        if (conn->fs_capabilities & FILE_FILE_COMPRESSION) {


-- 
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