smbd: reuse smb_fname->fsp in create_file_default()

This is the big bang for the internal pathref fsps: up to this point the pathref
fsps were lingering around unused inside smb_fname->fsp.

With this change, the internal fsp will be the one that is going to be returned
from SMB_VFS_CREATE_FILE() if the client requested access mask matches the
criteria in open_file():

	uint32_t need_fd_mask =
		FILE_READ_DATA |
		FILE_WRITE_DATA |
		FILE_APPEND_DATA |
		FILE_EXECUTE |
		WRITE_DAC_ACCESS |
		WRITE_OWNER_ACCESS |
		SEC_FLAG_SYSTEM_SECURITY |
		READ_CONTROL_ACCESS;

As long as the client doesn't request any of the access rights listed above, we
reuse the smb_fname->fsp, otherwise we close the smb_fname->fsp and call
fd_open() to open a new fsp.

In the future we can remove the four non-IO related access rights from the list:

		WRITE_DAC_ACCESS |
		WRITE_OWNER_ACCESS |
		SEC_FLAG_SYSTEM_SECURITY |
		READ_CONTROL_ACCESS

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

diff --git a/source3/smbd/open.c b/source3/smbd/open.c
index eef2e2faea9dc7a425dfbabcfc357c621ee950e0..106d827dcc94023484e5f58429de6ddd78c89c38 100644 (file)
--- a/source3/smbd/open.c
+++ b/source3/smbd/open.c
@@ -1366,6 +1366,16 @@ static NTSTATUS open_file(files_struct *fsp,
                        }
                }
 
+               /*
+                * Close the existing pathref fd and set fsp_flags.is_pathref to
+                * false so we get a full fd this time.
+                */
+               status = fd_close(fsp);
+               if (!NT_STATUS_IS_OK(status)) {
+                       return status;
+               }
+               fsp->fsp_flags.is_pathref = false;
+
                /*
                 * Actually do the open - if O_TRUNC is needed handle it
                 * below under the share mode lock.
@@ -1468,6 +1478,33 @@ static NTSTATUS open_file(files_struct *fsp,
                        return NT_STATUS_OBJECT_PATH_NOT_FOUND;
                }
 
+               if (!fsp->fsp_flags.is_pathref) {
+                       /*
+                        * There is only one legit case where end up here:
+                        * openat_pathref_fsp() failed to open a symlink, so the
+                        * fsp was created by fsp_new() which doesn't set
+                        * is_pathref. Other then that, we should always have a
+                        * pathref fsp at this point. The subsequent checks
+                        * assert this.
+                        */
+                       if (!(smb_fname->flags & SMB_FILENAME_POSIX_PATH)) {
+                               DBG_ERR("[%s] is not a POSIX pathname\n",
+                                       smb_fname_str_dbg(smb_fname));
+                               return NT_STATUS_INTERNAL_ERROR;
+                       }
+                       if (!S_ISLNK(smb_fname->st.st_ex_mode)) {
+                               DBG_ERR("[%s] is not a symlink\n",
+                                       smb_fname_str_dbg(smb_fname));
+                               return NT_STATUS_INTERNAL_ERROR;
+                       }
+                       if (fsp_get_pathref_fd(fsp) != -1) {
+                               DBG_ERR("fd for [%s] is not -1: fd [%d]\n",
+                                       smb_fname_str_dbg(smb_fname),
+                                       fsp_get_pathref_fd(fsp));
+                               return NT_STATUS_INTERNAL_ERROR;
+                       }
+               }
+
                status = smbd_check_access_rights(conn,
                                conn->cwd_fsp,
                                smb_fname,
@@ -4486,6 +4523,11 @@ static NTSTATUS open_directory(connection_struct *conn,
                }
        }
 
+       status = fd_close(fsp);
+       if (!NT_STATUS_IS_OK(status)) {
+               return status;
+       }
+
        /*
         * Setup the files_struct for it.
         */
@@ -4520,6 +4562,16 @@ static NTSTATUS open_directory(connection_struct *conn,
        */
        mtimespec = make_omit_timespec();
 
+       /*
+        * Close the existing pathref fd and set fsp_flags.is_pathref to
+        * false so we get a full fd this time.
+        */
+       status = fd_close(fsp);
+       if (!NT_STATUS_IS_OK(status)) {
+               return status;
+       }
+       fsp->fsp_flags.is_pathref = false;
+
        /* POSIX allows us to open a directory with O_RDONLY. */
        flags = O_RDONLY;
 #ifdef O_DIRECTORY
@@ -5658,14 +5710,45 @@ static NTSTATUS create_file_unixpath(connection_struct *conn,
                }
        }
 
-       status = file_new(req, conn, &fsp);
-       if(!NT_STATUS_IS_OK(status)) {
-               goto fail;
+       /*
+        * Now either reuse smb_fname->fsp or allocate a new fsp if
+        * smb_fname->fsp is NULL. The latter will be the case when processing a
+        * request to create a file that doesn't exist.
+        */
+       if (smb_fname->fsp != NULL) {
+               fsp = smb_fname->fsp;
+
+               /*
+                * Unlink the fsp from the smb_fname so the fsp is not
+                * autoclosed by the smb_fname pathref fsp talloc destructor.
+                */
+               smb_fname_fsp_unlink(smb_fname);
+
+               status = fsp_bind_smb(fsp, req);
+               if (!NT_STATUS_IS_OK(status)) {
+                       file_free(req, fsp);
+                       return status;
+               }
+
+               if (fsp->base_fsp != NULL) {
+                       fd_close(fsp->base_fsp);
+                       file_free(NULL, fsp->base_fsp);
+                       fsp->base_fsp = NULL;
+               }
        }
 
-       status = fsp_set_smb_fname(fsp, smb_fname);
-       if (!NT_STATUS_IS_OK(status)) {
-               goto fail;
+       if (fsp == NULL) {
+               /* Creating file */
+               status = file_new(req, conn, &fsp);
+               if(!NT_STATUS_IS_OK(status)) {
+                       goto fail;
+               }
+
+               status = fsp_set_smb_fname(fsp, smb_fname);
+               if (!NT_STATUS_IS_OK(status)) {
+                       goto fail;
+               }
+               fsp->fsp_name->fsp = fsp;
        }
 
        if (base_fsp) {