package/uclibc/0002-sunrpc-Do-not-use-alloca-in-clntudp_call.patch

   1 From 9213ad631513d0e67d9d31465c9cdb3f3dde0399 Mon Sep 17 00:00:00 2001
   2 From: Waldemar Brodkorb <wbx@uclibc-ng.org>
   3 Date: Fri, 5 Aug 2016 21:33:44 +0200
   4 Subject: [PATCH 2/3] sunrpc: Do not use alloca in clntudp_call
   5
   6 CVE-2016-4429:
   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 From GNU libc:
  16 https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commit;h=bc779a1a5b3035133024b21e2f339fe4219fb11c
  17
  18 Signed-off-by: Waldemar Brodkorb <wbx@uclibc-ng.org>
  19 ---
  20  libc/inet/rpc/clnt_udp.c | 10 +++++++++-
  21  1 file changed, 9 insertions(+), 1 deletion(-)
  22
  23 diff --git a/libc/inet/rpc/clnt_udp.c b/libc/inet/rpc/clnt_udp.c
  24 index 4fc55b7..ce7e9e6 100644
  25 --- a/libc/inet/rpc/clnt_udp.c
  26 +++ b/libc/inet/rpc/clnt_udp.c
  27 @@ -368,9 +368,15 @@ send_again:
  28           struct sock_extended_err *e;
  29           struct sockaddr_in err_addr;
  30           struct iovec iov;
  31 -         char *cbuf = (char *) alloca (outlen + 256);
  32 +         char *cbuf = malloc (outlen + 256);
  33           int ret;
  34
  35 +         if (cbuf == NULL)
  36 +           {
  37 +             cu->cu_error.re_errno = errno;
  38 +             return (cu->cu_error.re_status = RPC_CANTRECV);
  39 +           }
  40 +
  41           iov.iov_base = cbuf + 256;
  42           iov.iov_len = outlen;
  43           msg.msg_name = (void *) &err_addr;
  44 @@ -395,10 +401,12 @@ send_again:
  45                  cmsg = CMSG_NXTHDR (&msg, cmsg))
  46               if (cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_RECVERR)
  47                 {
  48 +                 free (cbuf);
  49                   e = (struct sock_extended_err *) CMSG_DATA(cmsg);
  50                   cu->cu_error.re_errno = e->ee_errno;
  51                   return (cu->cu_error.re_status = RPC_CANTRECV);
  52                 }
  53 +         free (cbuf);
  54         }
  55  #endif
  56        do
  57 --
  58 2.7.4 (Apple Git-66)
  59