* Don't iterate over each string three times; once is enough.
* Reject control characters (anything below space) in addition to the
double quote and backslash.
* If an unsafe character is encountered, discard the string instead of
rejecting the entire lease.
* If backslashes are encountered in the file name option, convert them
to forward slashes instead of rejecting the option.
* Tweak the warning messages a bit. Looking through the rest of the
code, it seems to me that notes generally end with a period while
warnings generally don't.
Approved by: so
Security: FreeBSD-EN-26:11.dhclient
Fixes: 8008e4b88d ("dhclient: Check for unexpected characters in some DHCP server options")
PR: 294886
MFC after: 1 week
Reviewed by: brooks, markj
Differential Revision: https://reviews.freebsd.org/D56740
(cherry picked from commit 873a195ba6)
(cherry picked from commit 2f9478ad42)
Dag-Erling Smørgrav
5bad905eb3