1 files changed, 77 insertions, 29 deletions

diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
index ee6ae74cd1b2..2baf93f8b8f5 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -139,6 +139,82 @@ buf_to_sg(struct scatterlist *sg, char *ptr, int len) {
         sg->length = len;
 }
 
+static int
+process_xdr_buf(struct xdr_buf *buf, int offset, int len,
+                int (*actor)(struct scatterlist *, void *), void *data)
+{
+        int i, page_len, thislen, page_offset, ret = 0;
+        struct scatterlist      sg[1];
+
+        if (offset >= buf->head[0].iov_len) {
+                offset -= buf->head[0].iov_len;
+        } else {
+                thislen = buf->head[0].iov_len - offset;
+                if (thislen > len)
+                        thislen = len;
+                buf_to_sg(sg, buf->head[0].iov_base + offset, thislen);
+                ret = actor(sg, data);
+                if (ret)
+                        goto out;
+                offset = 0;
+                len -= thislen;
+        }
+        if (len == 0)
+                goto out;
+
+        if (offset >= buf->page_len) {
+                offset -= buf->page_len;
+        } else {
+                page_len = buf->page_len - offset;
+                if (page_len > len)
+                        page_len = len;
+                len -= page_len;
+                page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
+                i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
+                thislen = PAGE_CACHE_SIZE - page_offset;
+                do {
+                        if (thislen > page_len)
+                                thislen = page_len;
+                        sg->page = buf->pages[i];
+                        sg->offset = page_offset;
+                        sg->length = thislen;
+                        ret = actor(sg, data);
+                        if (ret)
+                                goto out;
+                        page_len -= thislen;
+                        i++;
+                        page_offset = 0;
+                        thislen = PAGE_CACHE_SIZE;
+                } while (page_len != 0);
+                offset = 0;
+        }
+        if (len == 0)
+                goto out;
+
+        if (offset < buf->tail[0].iov_len) {
+                thislen = buf->tail[0].iov_len - offset;
+                if (thislen > len)
+                        thislen = len;
+                buf_to_sg(sg, buf->tail[0].iov_base + offset, thislen);
+                ret = actor(sg, data);
+                len -= thislen;
+        }
+        if (len != 0)
+                ret = -EINVAL;
+out:
+        return ret;
+}
+
+static int
+checksummer(struct scatterlist *sg, void *data)
+{
+        struct crypto_tfm *tfm = (struct crypto_tfm *)data;
+
+        crypto_digest_update(tfm, sg, 1);
+
+        return 0;
+}
+
 /* checksum the plaintext data and hdrlen bytes of the token header */
 s32
 make_checksum(s32 cksumtype, char *header, int hdrlen, struct xdr_buf *body,
@@ -148,8 +224,6 @@ make_checksum(s32 cksumtype, char *header, int hdrlen, struct xdr_buf *body,
         struct crypto_tfm               *tfm = NULL; /* XXX add to ctx? */
         struct scatterlist              sg[1];
         u32                             code = GSS_S_FAILURE;
-        int                             len, thislen, offset;
-        int                             i;
 
         switch (cksumtype) {
                 case CKSUMTYPE_RSA_MD5:
@@ -169,33 +243,7 @@ make_checksum(s32 cksumtype, char *header, int hdrlen, struct xdr_buf *body,
         crypto_digest_init(tfm);
         buf_to_sg(sg, header, hdrlen);
         crypto_digest_update(tfm, sg, 1);
-        if (body->head[0].iov_len) {
-                buf_to_sg(sg, body->head[0].iov_base, body->head[0].iov_len);
-                crypto_digest_update(tfm, sg, 1);
-        }
-
-        len = body->page_len;
-        if (len != 0) {
-                offset = body->page_base & (PAGE_CACHE_SIZE - 1);
-                i = body->page_base >> PAGE_CACHE_SHIFT;
-                thislen = PAGE_CACHE_SIZE - offset;
-                do {
-                        if (thislen > len)
-                                thislen = len;
-                        sg->page = body->pages[i];
-                        sg->offset = offset;
-                        sg->length = thislen;
-                        crypto_digest_update(tfm, sg, 1);
-                        len -= thislen;
-                        i++;
-                        offset = 0;
-                        thislen = PAGE_CACHE_SIZE;
-                } while(len != 0);
-        }
-        if (body->tail[0].iov_len) {
-                buf_to_sg(sg, body->tail[0].iov_base, body->tail[0].iov_len);
-                crypto_digest_update(tfm, sg, 1);
-        }
+        process_xdr_buf(body, 0, body->len, checksummer, tfm);
         crypto_digest_final(tfm, cksum->data);
         code = 0;
 out: