From 5d49283f885721f972e26c12c5d81264bebdc4fa Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Tue, 24 Nov 2020 16:18:47 +0000 Subject: [PATCH] pf: Make tag hashing more robust tagname2tag() hashes the tag name before truncating it to 63 characters. tag_unref() removes the tag from the name hash by computing the hash over the truncated name. Ensure that both operations compute the same hash for a given tag. The larger issue is a lack of string validation in pf(4) ioctl handlers. This is intended to be fixed with some future work, but an extra safety belt in tagname2hashindex() is worthwhile regardless. Reported by: syzbot+a0988828aafb00de7d68@syzkaller.appspotmail.com Reviewed by: kp MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D27346 --- sys/netpfil/pf/pf_ioctl.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/sys/netpfil/pf/pf_ioctl.c b/sys/netpfil/pf/pf_ioctl.c index a5757556dff..1be52e1e1a8 100644 --- a/sys/netpfil/pf/pf_ioctl.c +++ b/sys/netpfil/pf/pf_ioctl.c @@ -512,8 +512,10 @@ pf_cleanup_tagset(struct pf_tagset *ts) static uint16_t tagname2hashindex(const struct pf_tagset *ts, const char *tagname) { + size_t len; - return (murmur3_32_hash(tagname, strlen(tagname), ts->seed) & ts->mask); + len = strnlen(tagname, PF_TAG_NAME_SIZE - 1); + return (murmur3_32_hash(tagname, len, ts->seed) & ts->mask); } static uint16_t