Fixed some longstanding bugs in _getenv_static():

- malformed environment strings (ones without an '=') were not rejected.
  There shouldn't be any of these, but when the static environment is
  empty it always begins with one of these; this one should be considered
  as the terminator after the end of the environment, but it isn't.
- the comparison of the name being looked up with the name in the
  environment was fuzzy -- only the characters up to the length of the
  latter were compared, so _getenv_static("foobar") matched "foo=..."
  in the environment and everything matched "" in the empty environment.

MFC after:	3 days

1 files changed, 4 insertions, 3 deletions

diff --git a/sys/kern/kern_environment.c b/sys/kern/kern_environment.c
index 8c4d7dc..a5c5e08 100644
--- a/sys/kern/kern_environment.c
+++ b/sys/kern/kern_environment.c
@@ -238,10 +238,11 @@ _getenv_static(const char *name)
 	for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
 		for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
 			;
+		if (*ep != '=')
+			continue;
 		len = ep - cp;
-		if (*ep == '=')
-			ep++;
-		if (!strncmp(name, cp, len))
+		ep++;
+		if (!strncmp(name, cp, len) && name[len] == 0)
 			return (ep);
 	}
 	return (NULL);