dhclient: Improve server and filename validationstable/13

* 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.

Fixes:		8008e4b88daf ("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 873a195ba63575e46686cfd6ea9670a0ca340fa0)

0 files changed, 0 insertions, 0 deletions