UPSTREAM: netfilter: nfnetlink_osf: avoid OOB read

[ Upstream commit f4f8a78 ] The opt_num field is controlled by user mode and is not currently validated inside the kernel. An attacker can take advantage of this to trigger an OOB read and potentially leak information. BUG: KASAN: slab-out-of-bounds in nf_osf_match_one+0xbed/0xd10 net/netfilter/nfnetlink_osf.c:88 Read of size 2 at addr ffff88804bc64272 by task poc/6431 CPU: 1 PID: 6431 Comm: poc Not tainted 6.0.0-rc4 #1 Call Trace: nf_osf_match_one+0xbed/0xd10 net/netfilter/nfnetlink_osf.c:88 nf_osf_find+0x186/0x2f0 net/netfilter/nfnetlink_osf.c:281 nft_osf_eval+0x37f/0x590 net/netfilter/nft_osf.c:47 expr_call_ops_eval net/netfilter/nf_tables_core.c:214 nft_do_chain+0x2b0/0x1490 net/netfilter/nf_tables_core.c:264 nft_do_chain_ipv4+0x17c/0x1f0 net/netfilter/nft_chain_filter.c:23 [..] Also add validation to genre, subtype and version fields. Bug: 304913642 Fixes: 11eeef4 ("netfilter: passive OS fingerprint xtables match") Reported-by: Lucas Leong <[email protected]> Signed-off-by: Wander Lairson Costa <[email protected]> Signed-off-by: Florian Westphal <[email protected]> Signed-off-by: Sasha Levin <[email protected]> (cherry picked from commit 7bb8d52) Signed-off-by: Lee Jones <[email protected]> Change-Id: If79c79e3f55de8c81b70c19661cb0084b02c3da2
Kwiboo · Oct 23, 2023 · 44ddc37 · 44ddc37
1 parent ede2f9b
commit 44ddc37
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c
@@ -316,6 +316,14 @@ static int nfnl_osf_add_callback(struct net *net, struct sock *ctnl,
 
 	f = nla_data(osf_attrs[OSF_ATTR_FINGER]);
 
+	if (f->opt_num > ARRAY_SIZE(f->opt))
+		return -EINVAL;
+
+	if (!memchr(f->genre, 0, MAXGENRELEN) ||
+	    !memchr(f->subtype, 0, MAXGENRELEN) ||
+	    !memchr(f->version, 0, MAXGENRELEN))
+		return -EINVAL;
+
 	kf = kmalloc(sizeof(struct nf_osf_finger), GFP_KERNEL);
 	if (!kf)
 		return -ENOMEM;