From 39b8e7dcaf04cbdb926b478f825b160d852752b5 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 15 Jul 2015 17:13:32 +0100 Subject: [PATCH 1/7] rtl8139: avoid nested ifs in IP header parsing (CVE-2015-5165) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Transmit offload needs to parse packet headers. If header fields have unexpected values the offload processing is skipped. The code currently uses nested ifs because there is relatively little input validation. The next patches will add missing input validation and a goto label is more appropriate to avoid deep if statement nesting. Reported-by: 朱东海(启路) Reviewed-by: Jason Wang Signed-off-by: Stefan Hajnoczi --- hw/net/rtl8139.c | 41 ++++++++++++++++++++++------------------- 1 file changed, 22 insertions(+), 19 deletions(-) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index e0db4727ae..8731a30b71 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -2160,28 +2160,30 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) size_t eth_payload_len = 0; int proto = be16_to_cpu(*(uint16_t *)(saved_buffer + 12)); - if (proto == ETH_P_IP) + if (proto != ETH_P_IP) { - DPRINTF("+++ C+ mode has IP packet\n"); - - /* not aligned */ - eth_payload_data = saved_buffer + ETH_HLEN; - eth_payload_len = saved_size - ETH_HLEN; - - ip = (ip_header*)eth_payload_data; - - if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) { - DPRINTF("+++ C+ mode packet has bad IP version %d " - "expected %d\n", IP_HEADER_VERSION(ip), - IP_HEADER_VERSION_4); - ip = NULL; - } else { - hlen = IP_HEADER_LENGTH(ip); - ip_protocol = ip->ip_p; - ip_data_len = be16_to_cpu(ip->ip_len) - hlen; - } + goto skip_offload; } + DPRINTF("+++ C+ mode has IP packet\n"); + + /* not aligned */ + eth_payload_data = saved_buffer + ETH_HLEN; + eth_payload_len = saved_size - ETH_HLEN; + + ip = (ip_header*)eth_payload_data; + + if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) { + DPRINTF("+++ C+ mode packet has bad IP version %d " + "expected %d\n", IP_HEADER_VERSION(ip), + IP_HEADER_VERSION_4); + goto skip_offload; + } + + hlen = IP_HEADER_LENGTH(ip); + ip_protocol = ip->ip_p; + ip_data_len = be16_to_cpu(ip->ip_len) - hlen; + if (ip) { if (txdw0 & CP_TX_IPCS) @@ -2377,6 +2379,7 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) } } +skip_offload: /* update tally counter */ ++s->tally_counters.TxOk; From d6812d60e7932de3cd0f602c0ee63dd3d09f1847 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 15 Jul 2015 17:17:28 +0100 Subject: [PATCH 2/7] rtl8139: drop tautologous if (ip) {...} statement (CVE-2015-5165) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The previous patch stopped using the ip pointer as an indicator that the IP header is present. When we reach the if (ip) {...} statement we know ip is always non-NULL. Remove the if statement to reduce nesting. Reported-by: 朱东海(启路) Reviewed-by: Jason Wang Signed-off-by: Stefan Hajnoczi --- hw/net/rtl8139.c | 317 +++++++++++++++++++++++------------------------ 1 file changed, 157 insertions(+), 160 deletions(-) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index 8731a30b71..db36b65249 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -2184,198 +2184,195 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) ip_protocol = ip->ip_p; ip_data_len = be16_to_cpu(ip->ip_len) - hlen; - if (ip) + if (txdw0 & CP_TX_IPCS) { - if (txdw0 & CP_TX_IPCS) - { - DPRINTF("+++ C+ mode need IP checksum\n"); + DPRINTF("+++ C+ mode need IP checksum\n"); - if (hleneth_payload_len) {/* min header length */ - /* bad packet header len */ - /* or packet too short */ - } - else - { - ip->ip_sum = 0; - ip->ip_sum = ip_checksum(ip, hlen); - DPRINTF("+++ C+ mode IP header len=%d checksum=%04x\n", - hlen, ip->ip_sum); - } + if (hleneth_payload_len) {/* min header length */ + /* bad packet header len */ + /* or packet too short */ } - - if ((txdw0 & CP_TX_LGSEN) && ip_protocol == IP_PROTO_TCP) + else { - int large_send_mss = (txdw0 >> 16) & CP_TC_LGSEN_MSS_MASK; + ip->ip_sum = 0; + ip->ip_sum = ip_checksum(ip, hlen); + DPRINTF("+++ C+ mode IP header len=%d checksum=%04x\n", + hlen, ip->ip_sum); + } + } - DPRINTF("+++ C+ mode offloaded task TSO MTU=%d IP data %d " - "frame data %d specified MSS=%d\n", ETH_MTU, - ip_data_len, saved_size - ETH_HLEN, large_send_mss); + if ((txdw0 & CP_TX_LGSEN) && ip_protocol == IP_PROTO_TCP) + { + int large_send_mss = (txdw0 >> 16) & CP_TC_LGSEN_MSS_MASK; - int tcp_send_offset = 0; - int send_count = 0; + DPRINTF("+++ C+ mode offloaded task TSO MTU=%d IP data %d " + "frame data %d specified MSS=%d\n", ETH_MTU, + ip_data_len, saved_size - ETH_HLEN, large_send_mss); - /* maximum IP header length is 60 bytes */ - uint8_t saved_ip_header[60]; + int tcp_send_offset = 0; + int send_count = 0; - /* save IP header template; data area is used in tcp checksum calculation */ - memcpy(saved_ip_header, eth_payload_data, hlen); + /* maximum IP header length is 60 bytes */ + uint8_t saved_ip_header[60]; - /* a placeholder for checksum calculation routine in tcp case */ - uint8_t *data_to_checksum = eth_payload_data + hlen - 12; - // size_t data_to_checksum_len = eth_payload_len - hlen + 12; + /* save IP header template; data area is used in tcp checksum calculation */ + memcpy(saved_ip_header, eth_payload_data, hlen); - /* pointer to TCP header */ - tcp_header *p_tcp_hdr = (tcp_header*)(eth_payload_data + hlen); + /* a placeholder for checksum calculation routine in tcp case */ + uint8_t *data_to_checksum = eth_payload_data + hlen - 12; + // size_t data_to_checksum_len = eth_payload_len - hlen + 12; - int tcp_hlen = TCP_HEADER_DATA_OFFSET(p_tcp_hdr); + /* pointer to TCP header */ + tcp_header *p_tcp_hdr = (tcp_header*)(eth_payload_data + hlen); - /* ETH_MTU = ip header len + tcp header len + payload */ - int tcp_data_len = ip_data_len - tcp_hlen; - int tcp_chunk_size = ETH_MTU - hlen - tcp_hlen; + int tcp_hlen = TCP_HEADER_DATA_OFFSET(p_tcp_hdr); - DPRINTF("+++ C+ mode TSO IP data len %d TCP hlen %d TCP " - "data len %d TCP chunk size %d\n", ip_data_len, - tcp_hlen, tcp_data_len, tcp_chunk_size); + /* ETH_MTU = ip header len + tcp header len + payload */ + int tcp_data_len = ip_data_len - tcp_hlen; + int tcp_chunk_size = ETH_MTU - hlen - tcp_hlen; - /* note the cycle below overwrites IP header data, - but restores it from saved_ip_header before sending packet */ + DPRINTF("+++ C+ mode TSO IP data len %d TCP hlen %d TCP " + "data len %d TCP chunk size %d\n", ip_data_len, + tcp_hlen, tcp_data_len, tcp_chunk_size); - int is_last_frame = 0; + /* note the cycle below overwrites IP header data, + but restores it from saved_ip_header before sending packet */ - for (tcp_send_offset = 0; tcp_send_offset < tcp_data_len; tcp_send_offset += tcp_chunk_size) + int is_last_frame = 0; + + for (tcp_send_offset = 0; tcp_send_offset < tcp_data_len; tcp_send_offset += tcp_chunk_size) + { + uint16_t chunk_size = tcp_chunk_size; + + /* check if this is the last frame */ + if (tcp_send_offset + tcp_chunk_size >= tcp_data_len) { - uint16_t chunk_size = tcp_chunk_size; - - /* check if this is the last frame */ - if (tcp_send_offset + tcp_chunk_size >= tcp_data_len) - { - is_last_frame = 1; - chunk_size = tcp_data_len - tcp_send_offset; - } - - DPRINTF("+++ C+ mode TSO TCP seqno %08x\n", - be32_to_cpu(p_tcp_hdr->th_seq)); - - /* add 4 TCP pseudoheader fields */ - /* copy IP source and destination fields */ - memcpy(data_to_checksum, saved_ip_header + 12, 8); - - DPRINTF("+++ C+ mode TSO calculating TCP checksum for " - "packet with %d bytes data\n", tcp_hlen + - chunk_size); - - if (tcp_send_offset) - { - memcpy((uint8_t*)p_tcp_hdr + tcp_hlen, (uint8_t*)p_tcp_hdr + tcp_hlen + tcp_send_offset, chunk_size); - } - - /* keep PUSH and FIN flags only for the last frame */ - if (!is_last_frame) - { - TCP_HEADER_CLEAR_FLAGS(p_tcp_hdr, TCP_FLAG_PUSH|TCP_FLAG_FIN); - } - - /* recalculate TCP checksum */ - ip_pseudo_header *p_tcpip_hdr = (ip_pseudo_header *)data_to_checksum; - p_tcpip_hdr->zeros = 0; - p_tcpip_hdr->ip_proto = IP_PROTO_TCP; - p_tcpip_hdr->ip_payload = cpu_to_be16(tcp_hlen + chunk_size); - - p_tcp_hdr->th_sum = 0; - - int tcp_checksum = ip_checksum(data_to_checksum, tcp_hlen + chunk_size + 12); - DPRINTF("+++ C+ mode TSO TCP checksum %04x\n", - tcp_checksum); - - p_tcp_hdr->th_sum = tcp_checksum; - - /* restore IP header */ - memcpy(eth_payload_data, saved_ip_header, hlen); - - /* set IP data length and recalculate IP checksum */ - ip->ip_len = cpu_to_be16(hlen + tcp_hlen + chunk_size); - - /* increment IP id for subsequent frames */ - ip->ip_id = cpu_to_be16(tcp_send_offset/tcp_chunk_size + be16_to_cpu(ip->ip_id)); - - ip->ip_sum = 0; - ip->ip_sum = ip_checksum(eth_payload_data, hlen); - DPRINTF("+++ C+ mode TSO IP header len=%d " - "checksum=%04x\n", hlen, ip->ip_sum); - - int tso_send_size = ETH_HLEN + hlen + tcp_hlen + chunk_size; - DPRINTF("+++ C+ mode TSO transferring packet size " - "%d\n", tso_send_size); - rtl8139_transfer_frame(s, saved_buffer, tso_send_size, - 0, (uint8_t *) dot1q_buffer); - - /* add transferred count to TCP sequence number */ - p_tcp_hdr->th_seq = cpu_to_be32(chunk_size + be32_to_cpu(p_tcp_hdr->th_seq)); - ++send_count; + is_last_frame = 1; + chunk_size = tcp_data_len - tcp_send_offset; } - /* Stop sending this frame */ - saved_size = 0; - } - else if (txdw0 & (CP_TX_TCPCS|CP_TX_UDPCS)) - { - DPRINTF("+++ C+ mode need TCP or UDP checksum\n"); - - /* maximum IP header length is 60 bytes */ - uint8_t saved_ip_header[60]; - memcpy(saved_ip_header, eth_payload_data, hlen); - - uint8_t *data_to_checksum = eth_payload_data + hlen - 12; - // size_t data_to_checksum_len = eth_payload_len - hlen + 12; + DPRINTF("+++ C+ mode TSO TCP seqno %08x\n", + be32_to_cpu(p_tcp_hdr->th_seq)); /* add 4 TCP pseudoheader fields */ /* copy IP source and destination fields */ memcpy(data_to_checksum, saved_ip_header + 12, 8); - if ((txdw0 & CP_TX_TCPCS) && ip_protocol == IP_PROTO_TCP) + DPRINTF("+++ C+ mode TSO calculating TCP checksum for " + "packet with %d bytes data\n", tcp_hlen + + chunk_size); + + if (tcp_send_offset) { - DPRINTF("+++ C+ mode calculating TCP checksum for " - "packet with %d bytes data\n", ip_data_len); - - ip_pseudo_header *p_tcpip_hdr = (ip_pseudo_header *)data_to_checksum; - p_tcpip_hdr->zeros = 0; - p_tcpip_hdr->ip_proto = IP_PROTO_TCP; - p_tcpip_hdr->ip_payload = cpu_to_be16(ip_data_len); - - tcp_header* p_tcp_hdr = (tcp_header *) (data_to_checksum+12); - - p_tcp_hdr->th_sum = 0; - - int tcp_checksum = ip_checksum(data_to_checksum, ip_data_len + 12); - DPRINTF("+++ C+ mode TCP checksum %04x\n", - tcp_checksum); - - p_tcp_hdr->th_sum = tcp_checksum; + memcpy((uint8_t*)p_tcp_hdr + tcp_hlen, (uint8_t*)p_tcp_hdr + tcp_hlen + tcp_send_offset, chunk_size); } - else if ((txdw0 & CP_TX_UDPCS) && ip_protocol == IP_PROTO_UDP) + + /* keep PUSH and FIN flags only for the last frame */ + if (!is_last_frame) { - DPRINTF("+++ C+ mode calculating UDP checksum for " - "packet with %d bytes data\n", ip_data_len); - - ip_pseudo_header *p_udpip_hdr = (ip_pseudo_header *)data_to_checksum; - p_udpip_hdr->zeros = 0; - p_udpip_hdr->ip_proto = IP_PROTO_UDP; - p_udpip_hdr->ip_payload = cpu_to_be16(ip_data_len); - - udp_header *p_udp_hdr = (udp_header *) (data_to_checksum+12); - - p_udp_hdr->uh_sum = 0; - - int udp_checksum = ip_checksum(data_to_checksum, ip_data_len + 12); - DPRINTF("+++ C+ mode UDP checksum %04x\n", - udp_checksum); - - p_udp_hdr->uh_sum = udp_checksum; + TCP_HEADER_CLEAR_FLAGS(p_tcp_hdr, TCP_FLAG_PUSH|TCP_FLAG_FIN); } + /* recalculate TCP checksum */ + ip_pseudo_header *p_tcpip_hdr = (ip_pseudo_header *)data_to_checksum; + p_tcpip_hdr->zeros = 0; + p_tcpip_hdr->ip_proto = IP_PROTO_TCP; + p_tcpip_hdr->ip_payload = cpu_to_be16(tcp_hlen + chunk_size); + + p_tcp_hdr->th_sum = 0; + + int tcp_checksum = ip_checksum(data_to_checksum, tcp_hlen + chunk_size + 12); + DPRINTF("+++ C+ mode TSO TCP checksum %04x\n", + tcp_checksum); + + p_tcp_hdr->th_sum = tcp_checksum; + /* restore IP header */ memcpy(eth_payload_data, saved_ip_header, hlen); + + /* set IP data length and recalculate IP checksum */ + ip->ip_len = cpu_to_be16(hlen + tcp_hlen + chunk_size); + + /* increment IP id for subsequent frames */ + ip->ip_id = cpu_to_be16(tcp_send_offset/tcp_chunk_size + be16_to_cpu(ip->ip_id)); + + ip->ip_sum = 0; + ip->ip_sum = ip_checksum(eth_payload_data, hlen); + DPRINTF("+++ C+ mode TSO IP header len=%d " + "checksum=%04x\n", hlen, ip->ip_sum); + + int tso_send_size = ETH_HLEN + hlen + tcp_hlen + chunk_size; + DPRINTF("+++ C+ mode TSO transferring packet size " + "%d\n", tso_send_size); + rtl8139_transfer_frame(s, saved_buffer, tso_send_size, + 0, (uint8_t *) dot1q_buffer); + + /* add transferred count to TCP sequence number */ + p_tcp_hdr->th_seq = cpu_to_be32(chunk_size + be32_to_cpu(p_tcp_hdr->th_seq)); + ++send_count; } + + /* Stop sending this frame */ + saved_size = 0; + } + else if (txdw0 & (CP_TX_TCPCS|CP_TX_UDPCS)) + { + DPRINTF("+++ C+ mode need TCP or UDP checksum\n"); + + /* maximum IP header length is 60 bytes */ + uint8_t saved_ip_header[60]; + memcpy(saved_ip_header, eth_payload_data, hlen); + + uint8_t *data_to_checksum = eth_payload_data + hlen - 12; + // size_t data_to_checksum_len = eth_payload_len - hlen + 12; + + /* add 4 TCP pseudoheader fields */ + /* copy IP source and destination fields */ + memcpy(data_to_checksum, saved_ip_header + 12, 8); + + if ((txdw0 & CP_TX_TCPCS) && ip_protocol == IP_PROTO_TCP) + { + DPRINTF("+++ C+ mode calculating TCP checksum for " + "packet with %d bytes data\n", ip_data_len); + + ip_pseudo_header *p_tcpip_hdr = (ip_pseudo_header *)data_to_checksum; + p_tcpip_hdr->zeros = 0; + p_tcpip_hdr->ip_proto = IP_PROTO_TCP; + p_tcpip_hdr->ip_payload = cpu_to_be16(ip_data_len); + + tcp_header* p_tcp_hdr = (tcp_header *) (data_to_checksum+12); + + p_tcp_hdr->th_sum = 0; + + int tcp_checksum = ip_checksum(data_to_checksum, ip_data_len + 12); + DPRINTF("+++ C+ mode TCP checksum %04x\n", + tcp_checksum); + + p_tcp_hdr->th_sum = tcp_checksum; + } + else if ((txdw0 & CP_TX_UDPCS) && ip_protocol == IP_PROTO_UDP) + { + DPRINTF("+++ C+ mode calculating UDP checksum for " + "packet with %d bytes data\n", ip_data_len); + + ip_pseudo_header *p_udpip_hdr = (ip_pseudo_header *)data_to_checksum; + p_udpip_hdr->zeros = 0; + p_udpip_hdr->ip_proto = IP_PROTO_UDP; + p_udpip_hdr->ip_payload = cpu_to_be16(ip_data_len); + + udp_header *p_udp_hdr = (udp_header *) (data_to_checksum+12); + + p_udp_hdr->uh_sum = 0; + + int udp_checksum = ip_checksum(data_to_checksum, ip_data_len + 12); + DPRINTF("+++ C+ mode UDP checksum %04x\n", + udp_checksum); + + p_udp_hdr->uh_sum = udp_checksum; + } + + /* restore IP header */ + memcpy(eth_payload_data, saved_ip_header, hlen); } } From e1c120a9c54872f8a538ff9129d928de4e865cbd Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 15 Jul 2015 14:30:37 +0100 Subject: [PATCH 3/7] rtl8139: skip offload on short Ethernet/IP header (CVE-2015-5165) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Transmit offload features access Ethernet and IP headers the packet. If the packet is too short we must not attempt to access header fields: int proto = be16_to_cpu(*(uint16_t *)(saved_buffer + 12)); ... eth_payload_data = saved_buffer + ETH_HLEN; ... ip = (ip_header*)eth_payload_data; if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) { Reported-by: 朱东海(启路) Reviewed-by: Jason Wang Signed-off-by: Stefan Hajnoczi --- hw/net/rtl8139.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index db36b65249..1c620763d8 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -2150,6 +2150,11 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) { DPRINTF("+++ C+ mode offloaded task checksum\n"); + /* Large enough for Ethernet and IP headers? */ + if (saved_size < ETH_HLEN + sizeof(ip_header)) { + goto skip_offload; + } + /* ip packet header */ ip_header *ip = NULL; int hlen = 0; From 03247d43c577dfea8181cd40177ad5ba77c8db76 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 15 Jul 2015 17:32:32 +0100 Subject: [PATCH 4/7] rtl8139: check IP Header Length field (CVE-2015-5165) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The IP Header Length field was only checked in the IP checksum case, but is used in other cases too. Reported-by: 朱东海(启路) Reviewed-by: Jason Wang Signed-off-by: Stefan Hajnoczi --- hw/net/rtl8139.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index 1c620763d8..4eaa352f1a 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -2186,6 +2186,10 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) } hlen = IP_HEADER_LENGTH(ip); + if (hlen < sizeof(ip_header) || hlen > eth_payload_len) { + goto skip_offload; + } + ip_protocol = ip->ip_p; ip_data_len = be16_to_cpu(ip->ip_len) - hlen; @@ -2193,17 +2197,10 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) { DPRINTF("+++ C+ mode need IP checksum\n"); - if (hleneth_payload_len) {/* min header length */ - /* bad packet header len */ - /* or packet too short */ - } - else - { - ip->ip_sum = 0; - ip->ip_sum = ip_checksum(ip, hlen); - DPRINTF("+++ C+ mode IP header len=%d checksum=%04x\n", - hlen, ip->ip_sum); - } + ip->ip_sum = 0; + ip->ip_sum = ip_checksum(ip, hlen); + DPRINTF("+++ C+ mode IP header len=%d checksum=%04x\n", + hlen, ip->ip_sum); } if ((txdw0 & CP_TX_LGSEN) && ip_protocol == IP_PROTO_TCP) From c6296ea88df040054ccd781f3945fe103f8c7c17 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 15 Jul 2015 17:34:40 +0100 Subject: [PATCH 5/7] rtl8139: check IP Total Length field (CVE-2015-5165) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The IP Total Length field includes the IP header and data. Make sure it is valid and does not exceed the Ethernet payload size. Reported-by: 朱东海(启路) Reviewed-by: Jason Wang Signed-off-by: Stefan Hajnoczi --- hw/net/rtl8139.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index 4eaa352f1a..6859d7684e 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -2191,7 +2191,12 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) } ip_protocol = ip->ip_p; - ip_data_len = be16_to_cpu(ip->ip_len) - hlen; + + ip_data_len = be16_to_cpu(ip->ip_len); + if (ip_data_len < hlen || ip_data_len > eth_payload_len) { + goto skip_offload; + } + ip_data_len -= hlen; if (txdw0 & CP_TX_IPCS) { From 4240be45632db7831129f124bcf53c1223825b0f Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 15 Jul 2015 17:36:15 +0100 Subject: [PATCH 6/7] rtl8139: skip offload on short TCP header (CVE-2015-5165) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit TCP Large Segment Offload accesses the TCP header in the packet. If the packet is too short we must not attempt to access header fields: tcp_header *p_tcp_hdr = (tcp_header*)(eth_payload_data + hlen); int tcp_hlen = TCP_HEADER_DATA_OFFSET(p_tcp_hdr); Reported-by: 朱东海(启路) Reviewed-by: Jason Wang Signed-off-by: Stefan Hajnoczi --- hw/net/rtl8139.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index 6859d7684e..fa0193403e 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -2210,6 +2210,11 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) if ((txdw0 & CP_TX_LGSEN) && ip_protocol == IP_PROTO_TCP) { + /* Large enough for the TCP header? */ + if (ip_data_len < sizeof(tcp_header)) { + goto skip_offload; + } + int large_send_mss = (txdw0 >> 16) & CP_TC_LGSEN_MSS_MASK; DPRINTF("+++ C+ mode offloaded task TSO MTU=%d IP data %d " From 8357946b15f0a31f73dd691b7da95f29318ed310 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 15 Jul 2015 17:39:29 +0100 Subject: [PATCH 7/7] rtl8139: check TCP Data Offset field (CVE-2015-5165) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The TCP Data Offset field contains the length of the header. Make sure it is valid and does not exceed the IP data length. Reported-by: 朱东海(启路) Reviewed-by: Jason Wang Signed-off-by: Stefan Hajnoczi --- hw/net/rtl8139.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index fa0193403e..edbb61ccf3 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -2239,6 +2239,11 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) int tcp_hlen = TCP_HEADER_DATA_OFFSET(p_tcp_hdr); + /* Invalid TCP data offset? */ + if (tcp_hlen < sizeof(tcp_header) || tcp_hlen > ip_data_len) { + goto skip_offload; + } + /* ETH_MTU = ip header len + tcp header len + payload */ int tcp_data_len = ip_data_len - tcp_hlen; int tcp_chunk_size = ETH_MTU - hlen - tcp_hlen;