From 2e1dcbc0c2af64fcb17009eaf2ceedd81be2b27f Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Thu, 26 Nov 2020 19:27:06 +0530 Subject: [PATCH] slirp: check pkt_len before reading protocol header MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit While processing ARP/NCSI packets in 'arp_input' or 'ncsi_input' routines, ensure that pkt_len is large enough to accommodate the respective protocol headers, lest it should do an OOB access. Add check to avoid it. CVE-2020-29129 CVE-2020-29130 QEMU: slirp: out-of-bounds access while processing ARP/NCSI packets -> https://www.openwall.com/lists/oss-security/2020/11/27/1 Reported-by: Qiuhao Li Signed-off-by: Prasad J Pandit Message-Id: <20201126135706.273950-1-ppandit@redhat.com> Reviewed-by: Marc-André Lureau Signed-off-by: Peter Korsgaard --- src/ncsi.c | 4 ++++ src/slirp.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/src/ncsi.c b/src/ncsi.c index 3c1dfef..75dcc08 100644 --- a/src/ncsi.c +++ b/src/ncsi.c @@ -148,6 +148,10 @@ void ncsi_input(Slirp *slirp, const uint8_t *pkt, int pkt_len) uint32_t checksum; uint32_t *pchecksum; + if (pkt_len < ETH_HLEN + sizeof(struct ncsi_pkt_hdr)) { + return; /* packet too short */ + } + memset(ncsi_reply, 0, sizeof(ncsi_reply)); memset(reh->h_dest, 0xff, ETH_ALEN); diff --git a/src/slirp.c b/src/slirp.c index 9bead0c..abb6f9a 100644 --- a/src/slirp.c +++ b/src/slirp.c @@ -860,6 +860,10 @@ static void arp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len) return; } + if (pkt_len < ETH_HLEN + sizeof(struct slirp_arphdr)) { + return; /* packet too short */ + } + ar_op = ntohs(ah->ar_op); switch (ar_op) { case ARPOP_REQUEST: -- 2.20.1