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authorAlan Coopersmith <alan.coopersmith@oracle.com>2013-05-04 09:21:14 -0700
committerAlan Coopersmith <alan.coopersmith@oracle.com>2013-05-04 09:21:14 -0700
commit7ce3ce4be46087f9cc57cb415875abaaa961f734 (patch)
tree61fe6ebc9f4f3ea609dbe3a80b6bf32ab8a2eb68
parent470b9356af961ff7d3968b164aa73872b49a5dcc (diff)
Use _XEatDataWords to avoid overflow of _XEatData calculations
rep.length is a CARD32, so rep.length << 2 could overflow in 32-bit builds Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
-rw-r--r--configure.ac6
-rw-r--r--src/Xinerama.c19
2 files changed, 24 insertions, 1 deletions
diff --git a/configure.ac b/configure.ac
index e335508..046a1aa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -42,6 +42,12 @@ XORG_CHECK_MALLOC_ZERO
# Obtain compiler/linker options for depedencies
PKG_CHECK_MODULES(XINERAMA, x11 xext xextproto [xineramaproto >= 1.1.99.1])
+# Check for _XEatDataWords function that may be patched into older Xlib releases
+SAVE_LIBS="$LIBS"
+LIBS="$XINERAMA_LIBS"
+AC_CHECK_FUNCS([_XEatDataWords])
+LIBS="$SAVE_LIBS"
+
# Allow checking code with lint, sparse, etc.
XORG_WITH_LINT
LINT_FLAGS="${LINT_FLAGS} ${XINERAMA_CFLAGS}"
diff --git a/src/Xinerama.c b/src/Xinerama.c
index 7d7e4d8..04189b6 100644
--- a/src/Xinerama.c
+++ b/src/Xinerama.c
@@ -23,6 +23,10 @@ dealings in this Software without prior written authorization from Digital
Equipment Corporation.
******************************************************************/
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
#include <X11/Xlibint.h>
#include <X11/Xutil.h>
#include <X11/extensions/Xext.h>
@@ -31,6 +35,19 @@ Equipment Corporation.
#include <X11/extensions/panoramiXproto.h>
#include <X11/extensions/Xinerama.h>
+#ifndef HAVE__XEATDATAWORDS
+#include <X11/Xmd.h> /* for LONG64 on 64-bit platforms */
+#include <limits.h>
+
+static inline void _XEatDataWords(Display *dpy, unsigned long n)
+{
+# ifndef LONG64
+ if (n >= (ULONG_MAX >> 2))
+ _XIOError(dpy);
+# endif
+ _XEatData (dpy, n << 2);
+}
+#endif
static XExtensionInfo _panoramiX_ext_info_data;
static XExtensionInfo *panoramiX_ext_info = &_panoramiX_ext_info_data;
@@ -302,7 +319,7 @@ XineramaQueryScreens(
*number = rep.number;
} else
- _XEatData(dpy, rep.length << 2);
+ _XEatDataWords(dpy, rep.length);
} else {
*number = 0;
}