s3: VFS: fake_acls: In fake_acls_stat() - use openat_pathref_fsp() to always get...

Add a recursion guard so that openat_pathref_fsp() doesn't
end up recursing into itself when it calls SMB_VFS_STAT().

We now always have a valid fsp inside fake_acls_stat().

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

diff --git a/source3/modules/vfs_fake_acls.c b/source3/modules/vfs_fake_acls.c
index c675479cea717ae4cf3210dc49eee2fa7a92ccbd..5dd3cddccb795b311ef58eccf078b6ec21c937d7 100644 (file)
--- a/source3/modules/vfs_fake_acls.c
+++ b/source3/modules/vfs_fake_acls.c
@@ -112,14 +112,27 @@ static int fake_acls_stat(vfs_handle_struct *handle,
                           struct smb_filename *smb_fname)
 {
        int ret = -1;
+       static bool in_openat_pathref_fsp = false;
 
        ret = SMB_VFS_NEXT_STAT(handle, smb_fname);
        if (ret == 0) {
-               struct smb_filename smb_fname_base = {
-                       .base_name = smb_fname->base_name
-               };
+               struct smb_filename *smb_fname_cp = NULL;
                struct files_struct *fsp = NULL;
 
+               /*
+                * Ensure openat_pathref_fsp()
+                * can't recurse into fake_acls_stat().
+                * openat_pathref_fsp() doesn't care
+                * about the uid/gid values, it only
+                * wants a valid/invalid stat answer
+                * and we know smb_fname exists as
+                * the SMB_VFS_NEXT_STAT() returned
+                * zero above.
+                */
+               if (in_openat_pathref_fsp) {
+                       return 0;
+               }
+
                if (smb_fname->fsp != NULL) {
                        fsp = smb_fname->fsp;
                        if (fsp->base_fsp != NULL) {
@@ -129,6 +142,47 @@ static int fake_acls_stat(vfs_handle_struct *handle,
                                 */
                                fsp = fsp->base_fsp;
                        }
+               } else {
+                       NTSTATUS status;
+                       /*
+                        * openat_pathref_fsp() expects a talloc'ed
+                        * smb_filename. stat can be passed a struct
+                        * from the stack. Make a talloc'ed copy
+                        * so openat_pathref_fsp() can add its
+                        * destructor.
+                        */
+                       smb_fname_cp = cp_smb_filename(talloc_tos(),
+                                                      smb_fname);
+                       /* Recursion guard. */
+                       in_openat_pathref_fsp = true;
+                       status = openat_pathref_fsp(handle->conn->cwd_fsp,
+                                                   smb_fname_cp);
+                       /* End recursion guard. */
+                       in_openat_pathref_fsp = false;
+
+                       if (!NT_STATUS_IS_OK(status)) {
+                               /*
+                                * Ignore errors here. We know
+                                * the path exists (the SMB_VFS_NEXT_STAT()
+                                * above succeeded. So being unable to
+                                * open a pathref fsp can be due to a
+                                * range of errors (startup path beginning
+                                * with '/' for example, path = ".." when
+                                * enumerating a directory. Just treat this
+                                * the same way as the path not having the
+                                * FAKE_UID or FAKE_GID EA's present. For the
+                                * test purposes of this module (fake NT ACLs
+                                * from windows clients) this is close enough.
+                                * Just report for debugging purposes.
+                                */
+                               DBG_DEBUG("Unable to get pathref fsp on %s. "
+                                         "Error %s\n",
+                                         smb_fname_str_dbg(smb_fname_cp),
+                                         nt_errstr(status));
+                               TALLOC_FREE(smb_fname_cp);
+                               return 0;
+                       }
+                       fsp = smb_fname_cp->fsp;
                }
 
                if (fsp != NULL) {
@@ -136,10 +190,11 @@ static int fake_acls_stat(vfs_handle_struct *handle,
                                             fsp,
                                             &smb_fname->st.st_ex_uid);
                } else {
-                       ret = fake_acls_uid(handle, &smb_fname_base,
+                       ret = fake_acls_uid(handle, smb_fname_cp,
                                        &smb_fname->st.st_ex_uid);
                }
                if (ret != 0) {
+                       TALLOC_FREE(smb_fname_cp);
                        return ret;
                }
                if (fsp != NULL) {
@@ -147,12 +202,14 @@ static int fake_acls_stat(vfs_handle_struct *handle,
                                             fsp,
                                             &smb_fname->st.st_ex_gid);
                } else {
-                       ret = fake_acls_gid(handle, &smb_fname_base,
+                       ret = fake_acls_gid(handle, smb_fname_cp,
                                        &smb_fname->st.st_ex_gid);
                }
                if (ret != 0) {
+                       TALLOC_FREE(smb_fname_cp);
                        return ret;
                }
+               TALLOC_FREE(smb_fname_cp);
        }
 
        return ret;