gnu/packages/patches/glibc-CVE-2016-4429.patch

   1 From bdce95930e1d9a7d013d1ba78740243491262879 Mon Sep 17 00:00:00 2001
   2 From: Florian Weimer <fweimer@redhat.com>
   3 Date: Mon, 23 May 2016 20:18:34 +0200
   4 Subject: [PATCH] CVE-2016-4429: sunrpc: Do not use alloca in clntudp_call [BZ
   5  #20112]
   6
   7 The call is technically in a loop, and under certain circumstances
   8 (which are quite difficult to reproduce in a test case), alloca
   9 can be invoked repeatedly during a single call to clntudp_call.
  10 As a result, the available stack space can be exhausted (even
  11 though individual alloca sizes are bounded implicitly by what
  12 can fit into a UDP packet, as a side effect of the earlier
  13 successful send operation).
  14
  15 (cherry picked from commit bc779a1a5b3035133024b21e2f339fe4219fb11c)
  16 ---
  17  ChangeLog         |  7 +++++++
  18  NEWS              |  4 ++++
  19  sunrpc/clnt_udp.c | 10 +++++++++-
  20  3 files changed, 20 insertions(+), 1 deletion(-)
  21
  22 diff --git a/sunrpc/clnt_udp.c b/sunrpc/clnt_udp.c
  23 index a6cf5f1..4d9acb1 100644
  24 --- a/sunrpc/clnt_udp.c
  25 +++ b/sunrpc/clnt_udp.c
  26 @@ -388,9 +388,15 @@ send_again:
  27           struct sock_extended_err *e;
  28           struct sockaddr_in err_addr;
  29           struct iovec iov;
  30 -         char *cbuf = (char *) alloca (outlen + 256);
  31 +         char *cbuf = malloc (outlen + 256);
  32           int ret;
  33
  34 +         if (cbuf == NULL)
  35 +           {
  36 +             cu->cu_error.re_errno = errno;
  37 +             return (cu->cu_error.re_status = RPC_CANTRECV);
  38 +           }
  39 +
  40           iov.iov_base = cbuf + 256;
  41           iov.iov_len = outlen;
  42           msg.msg_name = (void *) &err_addr;
  43 @@ -415,10 +421,12 @@ send_again:
  44                  cmsg = CMSG_NXTHDR (&msg, cmsg))
  45               if (cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_RECVERR)
  46                 {
  47 +                 free (cbuf);
  48                   e = (struct sock_extended_err *) CMSG_DATA(cmsg);
  49                   cu->cu_error.re_errno = e->ee_errno;
  50                   return (cu->cu_error.re_status = RPC_CANTRECV);
  51                 }
  52 +         free (cbuf);
  53         }
  54  #endif
  55        do
  56 --
  57 2.9.3
  58