netfilter: xt_sctp: validate the flag_info count

commit e994764 upstream. sctp_mt_check doesn't validate the flag_count field. An attacker can take advantage of that to trigger a OOB read and leak memory information. Add the field validation in the checkentry function. Fixes: 2e4e6a1 ("[NETFILTER] x_tables: Abstraction layer for {ip,ip6,arp}_tables") Cc: [email protected] Reported-by: Lucas Leong <[email protected]> Signed-off-by: Wander Lairson Costa <[email protected]> Signed-off-by: Pablo Neira Ayuso <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx · Sep 23, 2023 · 64831fb · 64831fb
1 parent 28ce849
commit 64831fb
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/net/netfilter/xt_sctp.c b/net/netfilter/xt_sctp.c
@@ -150,6 +150,8 @@ static int sctp_mt_check(const struct xt_mtchk_param *par)
 {
 	const struct xt_sctp_info *info = par->matchinfo;
 
+	if (info->flag_count > ARRAY_SIZE(info->flag_info))
+		return -EINVAL;
 	if (info->flags & ~XT_SCTP_VALID_FLAGS)
 		return -EINVAL;
 	if (info->invflags & ~XT_SCTP_VALID_FLAGS)