Package: libtirpc / 0.2.5-1.2+deb9u1

10-CVE-2016-4429.diff Patch series | download
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From bc779a1a5b3035133024b21e2f339fe4219fb11c Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Mon, 23 May 2016 20:18:34 +0200
Subject: [PATCH] CVE-2016-4429: tirpc: Do not use alloca in clntudp_call [BZ #20112]

The call is technically in a loop, and under certain circumstances
(which are quite difficult to reproduce in a test case), alloca
can be invoked repeatedly during a single call to clntudp_call.
As a result, the available stack space can be exhausted (even
though individual alloca sizes are bounded implicitly by what
can fit into a UDP packet, as a side effect of the earlier
successful send operation).

[zeha@d.o: edited for libtirpc]


Index: libtirpc-0.2.5/src/clnt_dg.c
===================================================================
--- libtirpc-0.2.5.orig/src/clnt_dg.c
+++ libtirpc-0.2.5/src/clnt_dg.c
@@ -430,9 +430,15 @@ 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 = malloc (outlen + 256);
 	  int ret;
 
+      if (cbuf == NULL)
+        {
+          cu->cu_error.re_errno = errno;
+          return (cu->cu_error.re_status = RPC_CANTRECV);
+        }
+
 	  iov.iov_base = cbuf + 256;
 	  iov.iov_len = outlen;
 	  msg.msg_name = (void *) &err_addr;
@@ -457,11 +463,13 @@ get_reply:
 		 cmsg = CMSG_NXTHDR (&msg, cmsg))
 	      if (cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_RECVERR)
 		{
+          free (cbuf);
 		  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);
 	}
 #endif