[SUNRPC]: Make sure on-stack cmsg buffer is properly aligned.

Based upon a report from Meelis Roos.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 4 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 593f62ff8521..2772fee93881 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -452,6 +452,8 @@ union svc_pktinfo_u {
         struct in_pktinfo pkti;
         struct in6_pktinfo pkti6;
 };
+#define SVC_PKTINFO_SPACE \
+        CMSG_SPACE(sizeof(union svc_pktinfo_u))
 
 static void svc_set_cmsg_data(struct svc_rqst *rqstp, struct cmsghdr *cmh)
 {
@@ -491,8 +493,11 @@ svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
         struct svc_sock *svsk = rqstp->rq_sock;
         struct socket   *sock = svsk->sk_sock;
         int             slen;
-        char            buffer[CMSG_SPACE(sizeof(union svc_pktinfo_u))];
-        struct cmsghdr *cmh = (struct cmsghdr *)buffer;
+        union {
+                struct cmsghdr  hdr;
+                long            all[SVC_PKTINFO_SPACE / sizeof(long)];
+        } buffer;
+        struct cmsghdr *cmh = &buffer.hdr;
         int             len = 0;
         int             result;
         int             size;
@@ -745,8 +750,11 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
         struct svc_sock *svsk = rqstp->rq_sock;
         struct svc_serv *serv = svsk->sk_server;
         struct sk_buff  *skb;
-        char            buffer[CMSG_SPACE(sizeof(union svc_pktinfo_u))];
-        struct cmsghdr *cmh = (struct cmsghdr *)buffer;
+        union {
+                struct cmsghdr  hdr;
+                long            all[SVC_PKTINFO_SPACE / sizeof(long)];
+        } buffer;
+        struct cmsghdr *cmh = &buffer.hdr;
         int             err, len;
         struct msghdr msg = {
                 .msg_name = svc_addr(rqstp),