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Commit 01865335 authored by Karl Tomlinson's avatar Karl Tomlinson Committed by Ulrich Sibiller
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MakeBigReq: don't move the last word, already handled by Data32 (X.Org CVE-2013-7439).

MakeBigReq inserts a length field after the first 4 bytes of the request (after req->length), pushing everything else back by 4 bytes. The current memmove moves everything but the first 4 bytes back. If a request aligns to the end of the buffer pointer when MakeBigReq is invoked for that request, this runs over the buffer. Instead, we need to memmove minus the first 4 bytes (which aren't moved), minus the last 4 bytes (so we still align to the previous tail). The 4 bytes that fell out are already handled with Data32, which will handle the buffermax correctly. The case where req->length = 1 was already not functional. Reported by Abhishek Arya <inferno@chromium.org> (against X.Org BTS). https://bugzilla.mozilla.org/show_bug.cgi?id=803762Reviewed-by: 's avatarJeff Muizelaar <jmuizelaar@mozilla.com> Reviewed-by: 's avatarPeter Hutterer <peter.hutterer@who-t.net> Signed-off-by: 's avatarAlan Coopersmith <alan.coopersmith@oracle.com> Rebased-for-NX: Mike Gabriel <mike.gabriel@das-netzwerkteam.de> Re-applied after upgrade to libX11 1.3.4: Ulrich Sibiller <uli42@gmx.de>
parent 670b8ef6
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Showing with 17 additions and 2 deletions
nx-X11/lib/X11/Xlibint.h
View file @ 01865335
......@@ -543,6 +543,14 @@ extern LockInfoPtr _Xglobal_lock;
dpy->request++
#endif
/*
* MakeBigReq sets the CARD16 "req->length" to 0 and inserts a new CARD32
* length, after req->length, before the data in the request. The new length
* includes the "n" extra 32-bit words.
*
* Do not use MakeBigReq if there is no data already in the request.
* req->length must already be >= 2.
*/
#ifdef LONG64
#define MakeBigReq(req,n) \
{ \
......@@ -550,7 +558,7 @@ extern LockInfoPtr _Xglobal_lock;
CARD32 _BRlen = req->length - 1; \
req->length = 0; \
_BRdat = ((CARD32 *)req)[_BRlen]; \
memmove(((char *)req) + 8, ((char *)req) + 4, _BRlen << 2); \
memmove(((char *)req) + 8, ((char *)req) + 4, (_BRlen - 1) << 2); \
((CARD32 *)req)[1] = _BRlen + n + 2; \
Data32(dpy, &_BRdat, 4); \
}
......@@ -561,12 +569,19 @@ extern LockInfoPtr _Xglobal_lock;
CARD32 _BRlen = req->length - 1; \
req->length = 0; \
_BRdat = ((CARD32 *)req)[_BRlen]; \
memmove(((char *)req) + 8, ((char *)req) + 4, _BRlen << 2); \
memmove(((char *)req) + 8, ((char *)req) + 4, (_BRlen - 1) << 2); \
((CARD32 *)req)[1] = _BRlen + n + 2; \
Data32(dpy, &_BRdat, 4); \
}
#endif
/*
* SetReqLen increases the count of 32-bit words in the request by "n",
* or by "badlen" if "n" is too large.
*
* Do not use SetReqLen if "req" does not already have data after the
* xReq header. req->length must already be >= 2.
*/
#define SetReqLen(req,n,badlen) \
if ((req->length + n) > (unsigned)65535) { \
if (dpy->bigreq_size) { \
......
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