Re: [PATCH v2 0/6] unshare: Add support for mapping ranges of user/group IDs

[Daniel Gerber <dg@atufi.org>]

Hi,

Thanks for this feature. I've been trying it out... (This is with lib-musl-x86_64.)

Automatic mapping works:

$ unshare --map-users=auto cat /proc/self/uid_map
         0     100000      65536

But parsing id ranges does not:

$ unshare --map-users=100000,0,65536 cat /proc/self/uid_map
unshare: could not parse ID: '100000,0,65536'

Fix:
---
diff --git a/sys-utils/unshare.c b/sys-utils/unshare.c
index 443358952..52bd9702a 100644
--- a/sys-utils/unshare.c
+++ b/sys-utils/unshare.c
@@ -388,7 +388,7 @@ static int uint_to_id(const char *name, size_t sz)
 	char buf[UID_BUFSIZ];

 	mem2strcpy(buf, name, sz, sizeof(buf));
-	return strtoul_or_err(name, _("could not parse ID"));
+	return strtoul_or_err(buf, _("could not parse ID"));
 }

 /**
---

Then, the value passed to newuidmap is still incorrect:

$ unshare --map-users=100000,0,65536 cat /proc/self/uid_map
newuidmap: uid range [0-655360) -> [100000-755360) not allowed

$ unshare --map-users=100000,0,0065536 cat /proc/self/uid_map
         0     100000      65536

The count value gets zero-padded to the right at some place I've not pinned down.


Also, I would suggest adopting the same argument order as in /proc/<pid>/uid_map and newuidmap -- inner,outer,count.

This doc string has it reversed:
---
/**
 * struct map_range - A range of IDs to map
 * @outer: First ID inside the namespace
 * @inner: First ID outside the namespace
---

And this one has inconsistent terminology:
---
 * get_map_range() - Parse a mapping range from a string
 * @s: A string of the format upper,lower,count
 *
 * Parse a string of the form upper,lower,count into a new mapping range.
---


--
Daniel Gerber