Re: [PATCH nf v2] netfilter/osf: avoid OOB read
From: Florian Westphal <fw@strlen.de>
Date: 2023-08-31 13:38:08
Also in:
lkml, netfilter-devel
Wander Lairson Costa [off-list ref] wrote:
quoted hunk ↗ jump to hunk
diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c index 8f1bfa6ccc2d..13fedf2aaa0f 100644 --- a/net/netfilter/nfnetlink_osf.c +++ b/net/netfilter/nfnetlink_osf.c@@ -315,6 +315,9 @@ static int nfnl_osf_add_callback(struct sk_buff *skb, f = nla_data(osf_attrs[OSF_ATTR_FINGER]); + if (f->opt_num > ARRAY_SIZE(f->opt)) + return -EINVAL; +
Hmm, this isn't enough; as far as I can see there is no validation whatsover. This should also check that all of: char genre[MAXGENRELEN]; char version[MAXGENRELEN]; char subtype[MAXGENRELEN]; ... have a NUL byte. You could use strnlen() == ARRAY_SIZE() -> EINVAL for those. Maybe there is more to be validated, I did not followup with all the nested structures buried in user_finger struct.