Reject string longer than USHRT_MAX before sending them on the wire

The X protocol uses CARD16 values to represent the length so
this would overflow.

CVE-2021-31535

Signed-off-by: Matthieu Herrb <matthieu@herrb.eu>

12 files changed, 51 insertions, 4 deletions

diff --git a/src/Font.c b/src/Font.c
index d4ebdaca..1cd89cca 100644
--- a/src/Font.c
+++ b/src/Font.c
@@ -102,6 +102,8 @@ XFontStruct *XLoadQueryFont(
     XF86BigfontCodes *extcodes = _XF86BigfontCodes(dpy);
 #endif
 
+    if (strlen(name) >= USHRT_MAX)
+        return NULL;
     if (_XF86LoadQueryLocaleFont(dpy, name, &font_result, (Font *)0))
       return font_result;
     LockDisplay(dpy);
@@ -663,7 +665,7 @@ int _XF86LoadQueryLocaleFont(
     if (!name)
 	return 0;
     l = (int) strlen(name);
-    if (l < 2 || name[l - 1] != '*' || name[l - 2] != '-')
+    if (l < 2 || name[l - 1] != '*' || name[l - 2] != '-' || l >= USHRT_MAX)
 	return 0;
     charset = NULL;
     /* next three lines stolen from _XkbGetCharset() */
diff --git a/src/FontInfo.c b/src/FontInfo.c
index 694efa10..6644b3fa 100644
--- a/src/FontInfo.c
+++ b/src/FontInfo.c
@@ -58,6 +58,9 @@ XFontStruct **info)	/* RETURN */
     register xListFontsReq *req;
     int j;
 
+    if (strlen(pattern) >= USHRT_MAX)
+        return NULL;
+
     LockDisplay(dpy);
     GetReq(ListFontsWithInfo, req);
     req->maxNames = maxNames;
diff --git a/src/FontNames.c b/src/FontNames.c
index 30912925..458d80c9 100644
--- a/src/FontNames.c
+++ b/src/FontNames.c
@@ -51,6 +51,9 @@ int *actualCount)	/* RETURN */
     register xListFontsReq *req;
     unsigned long rlen = 0;
 
+    if (strlen(pattern) >= USHRT_MAX)
+        return NULL;
+
     LockDisplay(dpy);
     GetReq(ListFonts, req);
     req->maxNames = maxNames;
diff --git a/src/GetColor.c b/src/GetColor.c
index d088497f..c8178067 100644
--- a/src/GetColor.c
+++ b/src/GetColor.c
@@ -27,6 +27,7 @@ in this Software without prior written authorization from The Open Group.
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
+#include <limits.h>
 #include <stdio.h>
 #include "Xlibint.h"
 #include "Xcmsint.h"
@@ -48,6 +49,9 @@ XColor *exact_def) /* RETURN */
     XcmsColor cmsColor_exact;
     Status ret;
 
+    if (strlen(colorname) >= USHRT_MAX)
+        return (0);
+
 #ifdef XCMS
     /*
      * Let's Attempt to use Xcms and i18n approach to Parse Color
diff --git a/src/LoadFont.c b/src/LoadFont.c
index 0a3809a8..3996436f 100644
--- a/src/LoadFont.c
+++ b/src/LoadFont.c
@@ -27,6 +27,7 @@ in this Software without prior written authorization from The Open Group.
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
+#include <limits.h>
 #include "Xlibint.h"
 
 Font
@@ -38,6 +39,9 @@ XLoadFont (
     Font fid;
     register xOpenFontReq *req;
 
+    if (strlen(name) >= USHRT_MAX)
+        return (0);
+
     if (_XF86LoadQueryLocaleFont(dpy, name, (XFontStruct **)0, &fid))
       return fid;
 
diff --git a/src/LookupCol.c b/src/LookupCol.c
index 9608d512..cd9b1368 100644
--- a/src/LookupCol.c
+++ b/src/LookupCol.c
@@ -27,6 +27,7 @@ in this Software without prior written authorization from The Open Group.
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
+#include <limits.h>
 #include <stdio.h>
 #include "Xlibint.h"
 #include "Xcmsint.h"
@@ -46,6 +47,9 @@ XLookupColor (
 	XcmsCCC ccc;
 	XcmsColor cmsColor_exact;
 
+	n = (int) strlen (spec);
+	if (n >= USHRT_MAX)
+            return 0;
 #ifdef XCMS
 	/*
 	 * Let's Attempt to use Xcms and i18n approach to Parse Color
@@ -77,8 +81,6 @@ XLookupColor (
 	 * Xcms and i18n methods failed, so lets pass it to the server
 	 * for parsing.
 	 */
-
-	n = (int) strlen (spec);
 	LockDisplay(dpy);
 	GetReq (LookupColor, req);
 	req->cmap = cmap;
diff --git a/src/ParseCol.c b/src/ParseCol.c
index 2691df36..7a84a17b 100644
--- a/src/ParseCol.c
+++ b/src/ParseCol.c
@@ -27,6 +27,7 @@ in this Software without prior written authorization from The Open Group.
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
+#include <limits.h>
 #include <stdio.h>
 #include "Xlibint.h"
 #include "Xcmsint.h"
@@ -47,6 +48,8 @@ XParseColor (
 
         if (!spec) return(0);
 	n = (int) strlen (spec);
+	if (n >= USHRT_MAX)
+            return(0);
 	if (*spec == '#') {
 	    /*
 	     * RGB
diff --git a/src/QuExt.c b/src/QuExt.c
index 2021dca4..4cb99fcf 100644
--- a/src/QuExt.c
+++ b/src/QuExt.c
@@ -27,6 +27,8 @@ in this Software without prior written authorization from The Open Group.
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
+#include <limits.h>
+#include <stdbool.h>
 #include "Xlibint.h"
 
 Bool
@@ -40,6 +42,9 @@ XQueryExtension(
     xQueryExtensionReply rep;
     register xQueryExtensionReq *req;
 
+    if (strlen(name) >= USHRT_MAX)
+        return false;
+
     LockDisplay(dpy);
     GetReq(QueryExtension, req);
     req->nbytes = name ? (CARD16) strlen(name) : 0;
diff --git a/src/SetFPath.c b/src/SetFPath.c
index 7d12f18c..13fce49e 100644
--- a/src/SetFPath.c
+++ b/src/SetFPath.c
@@ -26,6 +26,7 @@ in this Software without prior written authorization from The Open Group.
 
 #ifdef HAVE_CONFIG_H
 #include <config.h>
+#include <limits.h>
 #endif
 #include "Xlibint.h"
 
@@ -49,6 +50,11 @@ XSetFontPath (
 	req->nFonts = ndirs;
 	for (i = 0; i < ndirs; i++) {
 		n = (int) ((size_t) n + (safestrlen (directories[i]) + 1));
+		if (n >= USHRT_MAX) {
+			UnlockDisplay(dpy);
+			SyncHandle();
+			return 0;
+		}
 	}
 	nbytes = (n + 3) & ~3;
 	req->length += nbytes >> 2;
diff --git a/src/SetHints.c b/src/SetHints.c
index e81aa9d3..61cb0684 100644
--- a/src/SetHints.c
+++ b/src/SetHints.c
@@ -49,6 +49,7 @@ SOFTWARE.
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
+#include <limits.h>
 #include <X11/Xlibint.h>
 #include <X11/Xutil.h>
 #include "Xatomtype.h"
@@ -214,6 +215,8 @@ XSetCommand (
 	register char *buf, *bp;
 	for (i = 0, nbytes = 0; i < argc; i++) {
 		nbytes += safestrlen(argv[i]) + 1;
+		if (nbytes >= USHRT_MAX)
+                    return 1;
 	}
 	if ((bp = buf = Xmalloc(nbytes))) {
 	    /* copy arguments into single buffer */
@@ -256,6 +259,8 @@ XSetStandardProperties (
 
 	if (name != NULL) XStoreName (dpy, w, name);
 
+        if (safestrlen(icon_string) >= USHRT_MAX)
+            return 1;
 	if (icon_string != NULL) {
 	    XChangeProperty (dpy, w, XA_WM_ICON_NAME, XA_STRING, 8,
                              PropModeReplace,
@@ -298,6 +303,8 @@ XSetClassHint(
 
 	len_nm = safestrlen(classhint->res_name);
 	len_cl = safestrlen(classhint->res_class);
+        if (len_nm + len_cl >= USHRT_MAX)
+            return 1;
 	if ((class_string = s = Xmalloc(len_nm + len_cl + 2))) {
 	    if (len_nm) {
 		strcpy(s, classhint->res_name);
diff --git a/src/StNColor.c b/src/StNColor.c
index 3b50401b..16dc9cbc 100644
--- a/src/StNColor.c
+++ b/src/StNColor.c
@@ -27,6 +27,7 @@ in this Software without prior written authorization from The Open Group.
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
+#include <limits.h>
 #include <stdio.h>
 #include "Xlibint.h"
 #include "Xcmsint.h"
@@ -46,6 +47,8 @@ int flags)  /* DoRed, DoGreen, DoBlue */
     XcmsColor cmsColor_exact;
     XColor scr_def;
 
+    if (strlen(name) >= USHRT_MAX)
+        return 0;
 #ifdef XCMS
     /*
      * Let's Attempt to use Xcms approach to Parse Color
diff --git a/src/StName.c b/src/StName.c
index 58b5a5a6..04bb3aa6 100644
--- a/src/StName.c
+++ b/src/StName.c
@@ -27,6 +27,7 @@ in this Software without prior written authorization from The Open Group.
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
+#include <limits.h>
 #include <X11/Xlibint.h>
 #include <X11/Xatom.h>
 
@@ -36,7 +37,9 @@ XStoreName (
     Window w,
     _Xconst char *name)
 {
-    return XChangeProperty(dpy, w, XA_WM_NAME, XA_STRING,
+    if (strlen(name) >= USHRT_MAX)
+        return 0;
+    return XChangeProperty(dpy, w, XA_WM_NAME, XA_STRING, /*  */
 			   8, PropModeReplace, (_Xconst unsigned char *)name,
 			   name ? (int) strlen(name) : 0);
 }
@@ -47,6 +50,8 @@ XSetIconName (
     Window w,
     _Xconst char *icon_name)
 {
+    if (strlen(icon_name) >= USHRT_MAX)
+        return 0;
     return XChangeProperty(dpy, w, XA_WM_ICON_NAME, XA_STRING, 8,
                            PropModeReplace, (_Xconst unsigned char *)icon_name,
 			   icon_name ? (int) strlen(icon_name) : 0);