net: fix misaligned member access

Fixes the following ASAN warnings:

/home/elmarco/src/qemu/hw/net/net_tx_pkt.c:201:27: runtime error: member access within misaligned address 0x631000028846 for type 'struct ip_header', which requires 4 byte alignment
0x631000028846: note: pointer points here
 01 00 00 00 45 00  01 a9 01 00 00 00 40 11  78 45 00 00 00 00 ff ff  ff ff 00 00 00 00 00 00  00 00
             ^
/home/elmarco/src/qemu/hw/net/net_tx_pkt.c:208:63: runtime error: member access within misaligned address 0x631000028846 for type 'struct ip_header', which requires 4 byte alignment
0x631000028846: note: pointer points here
 01 00 00 00 45 00  01 a9 01 00 00 00 40 11  78 45 00 00 00 00 ff ff  ff ff 00 00 00 00 00 00  00 00
             ^
/home/elmarco/src/qemu/hw/net/net_tx_pkt.c:210:13: runtime error: member access within misaligned address 0x631000028846 for type 'struct ip_header', which requires 4 byte alignment
0x631000028846: note: pointer points here
 01 00 00 00 45 00  01 a9 01 00 00 00 40 11  78 45 00 00 00 00 ff ff  ff ff 00 00 00 00 00 00  00 00

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20180209190340.19516-1-marcandre.lureau@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
index e29c881bc2c8a5e0968cf453115a92cf44d23fee..162f802dd77e09b89c0cb65583e82ddfcc1d3487 100644 (file)
--- a/hw/net/net_tx_pkt.c
+++ b/hw/net/net_tx_pkt.c
@@ -205,7 +205,7 @@ static bool net_tx_pkt_parse_headers(struct NetTxPkt *pkt)
             return false;
         }
 
-        pkt->l4proto = ((struct ip_header *) l3_hdr->iov_base)->ip_p;
+        pkt->l4proto = IP_HDR_GET_P(l3_hdr->iov_base);
 
         if (IP_HDR_GET_LEN(l3_hdr->iov_base) != sizeof(struct ip_header)) {
             /* copy optional IPv4 header data if any*/

diff --git a/include/net/eth.h b/include/net/eth.h
index 09054a506d6e7dfeb59729c29054a37d1391eefe..e6dc8a7ba06fcfc7b36e18b5e0bda47662068f04 100644 (file)
--- a/include/net/eth.h
+++ b/include/net/eth.h
@@ -194,7 +194,9 @@ struct tcp_hdr {
 #define PKT_GET_IP_HDR(p)         \
     ((struct ip_header *)(((uint8_t *)(p)) + eth_get_l2_hdr_length(p)))
 #define IP_HDR_GET_LEN(p)         \
-    ((((struct ip_header *)(p))->ip_ver_len & 0x0F) << 2)
+    ((ldub_p(p + offsetof(struct ip_header, ip_ver_len)) & 0x0F) << 2)
+#define IP_HDR_GET_P(p)                                           \
+    (ldub_p(p + offsetof(struct ip_header, ip_p)))
 #define PKT_GET_IP_HDR_LEN(p)     \
     (IP_HDR_GET_LEN(PKT_GET_IP_HDR(p)))
 #define PKT_GET_IP6_HDR(p)        \