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| author | Petr Písař <ppisar@redhat.com> | 2019-01-07 10:40:01 +0100 |
|---|---|---|
| committer | Slávek Banko <slavek.banko@axis.cz> | 2019-03-03 16:01:12 +0100 |
| commit | 6142d389db44b781e36399fe7c477c4879c0924b (patch) | |
| tree | 041da4dafe45f182e7d477130471c5b55eba937d | |
| parent | 177b748ba10ee43351643091ca42239205743dd8 (diff) | |
| download | libtdevnc-6142d389.tar.gz libtdevnc-6142d389.zip | |
Limit lenght to INT_MAX bytes in rfbProcessFileTransferReadBuffer()
This ammends 15bb719c03cc70f14c36a843dcb16ed69b405707 fix for a heap
out-of-bound write access in rfbProcessFileTransferReadBuffer() when
reading a transfered file content in a server. The former fix did not
work on platforms with a 32-bit int type (expected by rfbReadExact()).
CVE-2018-15127
<https://github.com/LibVNC/libvncserver/issues/243>
<https://github.com/LibVNC/libvncserver/issues/273>
(cherry picked from commit 09e8fc02f59f16e2583b34fe1a270c238bd9ffec)
| -rw-r--r-- | libvncserver/rfbserver.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/libvncserver/rfbserver.c b/libvncserver/rfbserver.c index 182d18b..91b9db3 100644 --- a/libvncserver/rfbserver.c +++ b/libvncserver/rfbserver.c @@ -83,6 +83,8 @@ #include <errno.h> /* strftime() */ #include <time.h> +/* INT_MAX */ +#include <limits.h> #ifdef LIBVNCSERVER_WITH_WEBSOCKETS #include "rfbssl.h" @@ -1469,8 +1471,11 @@ char *rfbProcessFileTransferReadBuffer(rfbClientPtr cl, uint32_t length) 0XFFFFFFFF, i.e. SIZE_MAX for 32-bit systems. On 64-bit systems, a length of 0XFFFFFFFF will safely be allocated since this check will never trigger and malloc() can digest length+1 without problems as length is a uint32_t. + We also later pass length to rfbReadExact() that expects a signed int type and + that might wrap on platforms with a 32-bit int type if length is bigger + than 0X7FFFFFFF. */ - if(length == SIZE_MAX) { + if(length == SIZE_MAX || length > INT_MAX) { rfbErr("rfbProcessFileTransferReadBuffer: too big file transfer length requested: %u", (unsigned int)length); rfbCloseClient(cl); return NULL; |