From: Christian Weisgerber <naddy@mips.inka.de>
Subject: got_repo_map_path()
To: gameoftrees@openbsd.org
Date: Wed, 21 Oct 2020 22:04:36 +0200

I tried to take another look at got_repo_map_path().

Reminder: If unveil() is disabled, some command line uses break.

$ cd /home/naddy/got    # a worktree
$ cd tog
$ got log -r /home/naddy/got.git tog.1
got: home/naddy/got/tog/tog.1: no such entry found in tree

The problem is in got_repo_map_path(), principally in the block
that starts with
                path = realpath(canonpath, NULL);

If unveil() is enabled, the realpath() call will fail, which looks
like a bug.

However, without unveil() the rest of the block is executed and
the example above ends up here:
                        /*
                         * Matched unrelated on-disk path.
                         * Treat it as repository-relative.
                         */

I'm struggling to understand the _intended_ semantics of the various
cases handled by realpath(), so I can't tell what's actually wrong.

Generally speaking, the idea of converting a relative path into an
absolute filesystem path and using that one again as relative path
inside the repository, well, that seems odd.

Help!?


To reproduce:

diff refs/heads/main refs/heads/nounveil
blob - f7f14b9cb2d386242d73d208d79ef3e9df874bab
blob + e8abfd8f8a549cb0eac59cacfe6c63c122afc494
--- got/got.c
+++ got/got.c
@@ -56,6 +56,8 @@
 #include "got_opentemp.h"
 #include "got_gotconfig.h"
 
+#define unveil(path, permissions)	0
+
 #ifndef nitems
 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
 #endif
blob - d15fdd1c19625c14f12b9ef6c2f0a764fc43a0da
blob + 39236a84794f208a9dfc20a6e981cf62b4cc6c0a
--- lib/privsep.c
+++ lib/privsep.c
@@ -47,6 +47,8 @@
 #include "got_lib_privsep.h"
 #include "got_lib_pack.h"
 
+#define unveil(path, permissions)	0
+
 #ifndef MIN
 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
 #endif
blob - 1b0d1ec057af633bce4d306c98106dd9eb8eedb2
blob + f9522ec74ce4d1f505126d38a18dcb11c792f9b8
--- tog/tog.c
+++ tog/tog.c
@@ -56,6 +56,8 @@
 #include "got_path.h"
 #include "got_worktree.h"
 
+#define unveil(path, permissions)	0
+
 #ifndef MIN
 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
 #endif
-- 
Christian "naddy" Weisgerber                          naddy@mips.inka.de