From: Sebastien Marie <semarie@kapouay.eu.org>
Subject: Re: Maybe strlen is unnecessary in kern_unveil.c
To: Bob Beck <beck@obtuse.com>
Cc: Christian Schulte <cs@schulte.it>, tech@openbsd.org
Date: Wed, 19 Nov 2025 16:31:59 +0100

Bob Beck <beck@obtuse.com> writes:

> like ah.  no?
>
> the point of it being named "size" and not "len" is to make it clear it is the size of the allocation and not the length of a string. 
>
> renaming it to len  makes it confusing, which is only partly mitigated by a comment. this is not a helpful visit to the bikeshed paint store 

my point is the following code panic, because we are currently passing
cn_nameptr which isn't a NUL terminated string.

But I could rework the diff to ensure that we always pass NUL terminated
string (and not the opposite).

diff --git a/sys/kern/kern_unveil.c b/sys/kern/kern_unveil.c
index 492269e48a..b59b53edb7 100644
--- a/sys/kern/kern_unveil.c
+++ b/sys/kern/kern_unveil.c
@@ -74,12 +74,13 @@
 struct unvname *
 unvname_new(const char *name, size_t size, u_char flags)
 {
 	struct unvname *ret = malloc(sizeof(struct unvname), M_PROC, M_WAITOK);
 	ret->un_name = malloc(size, M_PROC, M_WAITOK);
 	memcpy(ret->un_name, name, size);
+	KASSERT(ret->un_name[size-1] == '\0');
 	ret->un_namesize = size;
 	ret->un_flags = flags;
 	return ret;
 }
 
 void

Regards.
-- 
Sebastien Marie