59 lines
1.8 KiB
Diff
59 lines
1.8 KiB
Diff
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From bdce95930e1d9a7d013d1ba78740243491262879 Mon Sep 17 00:00:00 2001
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From: Florian Weimer <fweimer@redhat.com>
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Date: Mon, 23 May 2016 20:18:34 +0200
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Subject: [PATCH] CVE-2016-4429: sunrpc: Do not use alloca in clntudp_call [BZ
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#20112]
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The call is technically in a loop, and under certain circumstances
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(which are quite difficult to reproduce in a test case), alloca
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can be invoked repeatedly during a single call to clntudp_call.
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As a result, the available stack space can be exhausted (even
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though individual alloca sizes are bounded implicitly by what
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can fit into a UDP packet, as a side effect of the earlier
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successful send operation).
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(cherry picked from commit bc779a1a5b3035133024b21e2f339fe4219fb11c)
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---
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ChangeLog | 7 +++++++
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NEWS | 4 ++++
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sunrpc/clnt_udp.c | 10 +++++++++-
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3 files changed, 20 insertions(+), 1 deletion(-)
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diff --git a/sunrpc/clnt_udp.c b/sunrpc/clnt_udp.c
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index a6cf5f1..4d9acb1 100644
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--- a/sunrpc/clnt_udp.c
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+++ b/sunrpc/clnt_udp.c
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@@ -388,9 +388,15 @@ send_again:
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struct sock_extended_err *e;
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struct sockaddr_in err_addr;
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struct iovec iov;
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- char *cbuf = (char *) alloca (outlen + 256);
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+ char *cbuf = malloc (outlen + 256);
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int ret;
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+ if (cbuf == NULL)
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+ {
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+ cu->cu_error.re_errno = errno;
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+ return (cu->cu_error.re_status = RPC_CANTRECV);
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+ }
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+
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iov.iov_base = cbuf + 256;
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iov.iov_len = outlen;
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msg.msg_name = (void *) &err_addr;
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@@ -415,10 +421,12 @@ send_again:
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cmsg = CMSG_NXTHDR (&msg, cmsg))
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if (cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_RECVERR)
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{
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+ free (cbuf);
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e = (struct sock_extended_err *) CMSG_DATA(cmsg);
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cu->cu_error.re_errno = e->ee_errno;
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return (cu->cu_error.re_status = RPC_CANTRECV);
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}
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+ free (cbuf);
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}
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#endif
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do
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--
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2.9.3
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