[PATCH V2] clnt_dg_call: Change the memory allocation

[Steve Dickson <steved@redhat.com>]

Commit 2936f109590e add free()s on memory that
was allocated from the stack (via alloca()).
That type memory is automatically freed so
those added free()s was causing a double frees.

It was suggested allocating memory from the
stack can be a bit troublesome. So this patch
changes the memory allocation from the stack
to the heap which also eliminates the double frees.

Fixes: 2936f109590e ("clnt_dg_call: Fix a buffer overflow (CVE-2016-4429)")
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1552163

Signed-off-by: Steve Dickson <steved@redhat.com>
---
 src/clnt_dg.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/clnt_dg.c b/src/clnt_dg.c
index 884a2db..04a2aba 100644
--- a/src/clnt_dg.c
+++ b/src/clnt_dg.c
@@ -430,7 +430,7 @@ get_reply:
 	  struct sockaddr_in err_addr;
 	  struct sockaddr_in *sin = (struct sockaddr_in *)&cu->cu_raddr;
 	  struct iovec iov;
-	  char *cbuf = (char *) alloca (outlen + 256);
+	  char *cbuf = (char *) mem_alloc((outlen + 256));
 	  int ret;
 
 	  if (cbuf == NULL) 
@@ -462,13 +462,13 @@ get_reply:
 		 cmsg = CMSG_NXTHDR (&msg, cmsg))
 	      if (cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_RECVERR)
 		{
-		  free(cbuf);
+		  mem_free(cbuf, (outlen + 256));
 		  e = (struct sock_extended_err *) CMSG_DATA(cmsg);
 		  cu->cu_error.re_errno = e->ee_errno;
 		  release_fd_lock(cu->cu_fd, mask);
 		  return (cu->cu_error.re_status = RPC_CANTRECV);
 		}
-	  free(cbuf);
+	  mem_free(cbuf, (outlen + 256));
 	}
 #endif
 
-- 
2.14.3