1 files changed, 37 insertions, 16 deletions

diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index 0c24b9e24fe8..cb3e7fadb772 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -231,9 +231,10 @@ int
 nfssvc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p,
                                         struct nfsd_sattrargs *args)
 {
-        if (!(p = decode_fh(p, &args->fh))
-         || !(p = decode_sattr(p, &args->attrs)))
+        p = decode_fh(p, &args->fh);
+        if (!p)
                 return 0;
+        p = decode_sattr(p, &args->attrs);
 
         return xdr_argsize_check(rqstp, p);
 }
@@ -284,8 +285,9 @@ int
 nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p,
                                         struct nfsd_writeargs *args)
 {
-        unsigned int len;
+        unsigned int len, hdr, dlen;
         int v;
+
         if (!(p = decode_fh(p, &args->fh)))
                 return 0;
 
@@ -293,11 +295,30 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p,
         args->offset = ntohl(*p++);     /* offset */
         p++;                            /* totalcount */
         len = args->len = ntohl(*p++);
-        rqstp->rq_vec[0].iov_base = (void*)p;
-        rqstp->rq_vec[0].iov_len = rqstp->rq_arg.head[0].iov_len -
-                                (((void*)p) - rqstp->rq_arg.head[0].iov_base);
+        /*
+         * The protocol specifies a maximum of 8192 bytes.
+         */
         if (len > NFSSVC_MAXBLKSIZE_V2)
-                len = NFSSVC_MAXBLKSIZE_V2;
+                return 0;
+
+        /*
+         * Check to make sure that we got the right number of
+         * bytes.
+         */
+        hdr = (void*)p - rqstp->rq_arg.head[0].iov_base;
+        dlen = rqstp->rq_arg.head[0].iov_len + rqstp->rq_arg.page_len
+                - hdr;
+
+        /*
+         * Round the length of the data which was specified up to
+         * the next multiple of XDR units and then compare that
+         * against the length which was actually received.
+         */
+        if (dlen != XDR_QUADLEN(len)*4)
+                return 0;
+
+        rqstp->rq_vec[0].iov_base = (void*)p;
+        rqstp->rq_vec[0].iov_len = rqstp->rq_arg.head[0].iov_len - hdr;
         v = 0;
         while (len > rqstp->rq_vec[v].iov_len) {
                 len -= rqstp->rq_vec[v].iov_len;
@@ -306,18 +327,18 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p,
                 rqstp->rq_vec[v].iov_len = PAGE_SIZE;
         }
         rqstp->rq_vec[v].iov_len = len;
-        args->vlen = v+1;
-        return rqstp->rq_vec[0].iov_len > 0;
+        args->vlen = v + 1;
+        return 1;
 }
 
 int
 nfssvc_decode_createargs(struct svc_rqst *rqstp, __be32 *p,
                                         struct nfsd_createargs *args)
 {
-        if (!(p = decode_fh(p, &args->fh))
-         || !(p = decode_filename(p, &args->name, &args->len))
-         || !(p = decode_sattr(p, &args->attrs)))
+        if (   !(p = decode_fh(p, &args->fh))
+            || !(p = decode_filename(p, &args->name, &args->len)))
                 return 0;
+        p = decode_sattr(p, &args->attrs);
 
         return xdr_argsize_check(rqstp, p);
 }
@@ -361,11 +382,11 @@ int
 nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p,
                                         struct nfsd_symlinkargs *args)
 {
-        if (!(p = decode_fh(p, &args->ffh))
-         || !(p = decode_filename(p, &args->fname, &args->flen))
-         || !(p = decode_pathname(p, &args->tname, &args->tlen))
-         || !(p = decode_sattr(p, &args->attrs)))
+        if (   !(p = decode_fh(p, &args->ffh))
+            || !(p = decode_filename(p, &args->fname, &args->flen))
+            || !(p = decode_pathname(p, &args->tname, &args->tlen)))
                 return 0;
+        p = decode_sattr(p, &args->attrs);
 
         return xdr_argsize_check(rqstp, p);
 }