45 lines
1.8 KiB
Diff
45 lines
1.8 KiB
Diff
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From 09e8fc02f59f16e2583b34fe1a270c238bd9ffec Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
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Date: Mon, 7 Jan 2019 10:40:01 +0100
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Subject: [PATCH] Limit lenght to INT_MAX bytes in
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rfbProcessFileTransferReadBuffer()
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This ammends 15bb719c03cc70f14c36a843dcb16ed69b405707 fix for a heap
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out-of-bound write access in rfbProcessFileTransferReadBuffer() when
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reading a transfered file content in a server. The former fix did not
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work on platforms with a 32-bit int type (expected by rfbReadExact()).
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CVE-2018-15127
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<https://github.com/LibVNC/libvncserver/issues/243>
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<https://github.com/LibVNC/libvncserver/issues/273>
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---
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libvncserver/rfbserver.c | 7 ++++++-
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1 file changed, 6 insertions(+), 1 deletion(-)
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diff --git a/libvncserver/rfbserver.c b/libvncserver/rfbserver.c
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index 7af84906..f2edbeea 100644
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--- a/libvncserver/rfbserver.c
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+++ b/libvncserver/rfbserver.c
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@@ -88,6 +88,8 @@
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#include <errno.h>
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/* strftime() */
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#include <time.h>
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+/* INT_MAX */
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+#include <limits.h>
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#ifdef LIBVNCSERVER_WITH_WEBSOCKETS
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#include "rfbssl.h"
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@@ -1472,8 +1474,11 @@ char *rfbProcessFileTransferReadBuffer(rfbClientPtr cl, uint32_t length)
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0XFFFFFFFF, i.e. SIZE_MAX for 32-bit systems. On 64-bit systems, a length of 0XFFFFFFFF
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will safely be allocated since this check will never trigger and malloc() can digest length+1
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without problems as length is a uint32_t.
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+ We also later pass length to rfbReadExact() that expects a signed int type and
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+ that might wrap on platforms with a 32-bit int type if length is bigger
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+ than 0X7FFFFFFF.
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*/
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- if(length == SIZE_MAX) {
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+ if(length == SIZE_MAX || length > INT_MAX) {
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rfbErr("rfbProcessFileTransferReadBuffer: too big file transfer length requested: %u", (unsigned int)length);
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rfbCloseClient(cl);
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return NULL;
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