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authorFlorian Weimer <fweimer@redhat.com>2017-02-27 19:05:13 +0100
committerFlorian Weimer <fweimer@redhat.com>2017-02-27 19:05:13 +0100
commitd42eed4a044e5e10dfb885cf9891c2518a72a491 (patch)
tree29deb103217e1b09902f05cf49029a93cb76ad1a /sunrpc/clnt_udp.c
parent963394a22b38c4ec92b6875a6c06d3b15d5c0d21 (diff)
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sunrpc: Avoid use-after-free read access in clntudp_call [BZ #21115]
After commit bc779a1a5b3035133024b21e2f339fe4219fb11c
(CVE-2016-4429: sunrpc: Do not use alloca in clntudp_call
[BZ #20112]), ancillary data is stored on the heap,
but it is accessed after it has been freed.

The test case must be run under a heap debugger such as valgrind
to observe the invalid access.  A malloc implementation which
immediately calls munmap on free would catch this bug as well.
Diffstat (limited to 'sunrpc/clnt_udp.c')
-rw-r--r--sunrpc/clnt_udp.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/sunrpc/clnt_udp.c b/sunrpc/clnt_udp.c
index 4d9acb1e6a..1de25cb771 100644
--- a/sunrpc/clnt_udp.c
+++ b/sunrpc/clnt_udp.c
@@ -421,9 +421,9 @@ send_again:
 		 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;
+		  free (cbuf);
 		  return (cu->cu_error.re_status = RPC_CANTRECV);
 		}
 	  free (cbuf);