From 3bb29f45604ac6890f4ea5cdcbd1a62e6dad14a7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= Date: Wed, 16 Jan 2019 16:27:33 +0100 Subject: [PATCH 2/2] Fix possible crash when loading corrupted file Some values passes internal triggers by coincidence. Fix the check and check also first_node_offset before even passing it further. --- lib/dns/rbt.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/lib/dns/rbt.c b/lib/dns/rbt.c index 62d0826..b029b7d 100644 --- a/lib/dns/rbt.c +++ b/lib/dns/rbt.c @@ -787,7 +787,7 @@ treefix(dns_rbt_t *rbt, void *base, size_t filesize, dns_rbtnode_t *n, return (ISC_R_SUCCESS); CONFIRM((void *) n >= base); - CONFIRM((char *) n - (char *) base <= (int) nodemax); + CONFIRM((size_t)((char *) n - (char *) base) <= nodemax); CONFIRM(DNS_RBTNODE_VALID(n)); dns_name_init(&nodename, NULL); @@ -939,7 +939,8 @@ dns_rbt_deserialize_tree(void *base_address, size_t filesize, rbt->root = (dns_rbtnode_t *)((char *)base_address + header_offset + header->first_node_offset); - if ((header->nodecount * sizeof(dns_rbtnode_t)) > filesize) { + if ((header->nodecount * sizeof(dns_rbtnode_t)) > filesize + || header->first_node_offset > filesize) { result = ISC_R_INVALIDFILE; goto cleanup; } -- 2.20.1