3 files changed, 51 insertions, 2 deletions

diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c
index 107c4528654f..88edec929d73 100644
--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
@@ -574,6 +574,8 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
         buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
         buf->len -= GSS_KRB5_TOK_HDR_LEN + headskip;
 
+        /* Trim off the checksum blob */
+        xdr_buf_trim(buf, GSS_KRB5_TOK_HDR_LEN + tailskip);
         return GSS_S_COMPLETE;
 }
 
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 73e957386600..a5b41e2ac25a 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -817,13 +817,17 @@ read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj)
  *      The server uses base of head iovec as read pointer, while the
  *      client uses separate pointer. */
 static int
-unwrap_integ_data(struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
+unwrap_integ_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
 {
         int stat = -EINVAL;
         u32 integ_len, maj_stat;
         struct xdr_netobj mic;
         struct xdr_buf integ_buf;
 
+        /* Did we already verify the signature on the original pass through? */
+        if (rqstp->rq_deferred)
+                return 0;
+
         integ_len = svc_getnl(&buf->head[0]);
         if (integ_len & 3)
                 return stat;
@@ -846,6 +850,8 @@ unwrap_integ_data(struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
                 goto out;
         if (svc_getnl(&buf->head[0]) != seq)
                 goto out;
+        /* trim off the mic at the end before returning */
+        xdr_buf_trim(buf, mic.len + 4);
         stat = 0;
 out:
         kfree(mic.data);
@@ -1190,7 +1196,7 @@ svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
                         /* placeholders for length and seq. number: */
                         svc_putnl(resv, 0);
                         svc_putnl(resv, 0);
-                        if (unwrap_integ_data(&rqstp->rq_arg,
+                        if (unwrap_integ_data(rqstp, &rqstp->rq_arg,
                                         gc->gc_seq, rsci->mechctx))
                                 goto garbage_args;
                         break;
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 56055632f151..75edcfad6e26 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -879,6 +879,47 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
 }
 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
 
+/**
+ * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
+ * @buf: buf to be trimmed
+ * @len: number of bytes to reduce "buf" by
+ *
+ * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
+ * that it's possible that we'll trim less than that amount if the xdr_buf is
+ * too small, or if (for instance) it's all in the head and the parser has
+ * already read too far into it.
+ */
+void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
+{
+        size_t cur;
+        unsigned int trim = len;
+
+        if (buf->tail[0].iov_len) {
+                cur = min_t(size_t, buf->tail[0].iov_len, trim);
+                buf->tail[0].iov_len -= cur;
+                trim -= cur;
+                if (!trim)
+                        goto fix_len;
+        }
+
+        if (buf->page_len) {
+                cur = min_t(unsigned int, buf->page_len, trim);
+                buf->page_len -= cur;
+                trim -= cur;
+                if (!trim)
+                        goto fix_len;
+        }
+
+        if (buf->head[0].iov_len) {
+                cur = min_t(size_t, buf->head[0].iov_len, trim);
+                buf->head[0].iov_len -= cur;
+                trim -= cur;
+        }
+fix_len:
+        buf->len -= (len - trim);
+}
+EXPORT_SYMBOL_GPL(xdr_buf_trim);
+
 static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
 {
         unsigned int this_len;