From 5c539ee6aba5872fcc73aa3d46a4e9a33dc030db Mon Sep 17 00:00:00 2001 From: Matthieu Herrb Date: Fri, 19 Feb 2021 15:30:39 +0100 Subject: [PATCH] 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 https://lists.x.org/archives/xorg-announce/2021-May/003088.html XLookupColor() and other X libraries function lack proper validation of the length of their string parameters. If those parameters can be controlled by an external application (for instance a color name that can be emitted via a terminal control sequence) it can lead to the emission of extra X protocol requests to the X server. Upstream-Status: Backport [https://gitlab.freedesktop.org/xorg/lib/libx11/-/commit/8d2e02ae650f00c4a53deb625211a0527126c605] CVE: CVE-2021-31535 Signed-off-by: Jasper Orschulko --- src/Font.c | 6 ++++-- src/FontInfo.c | 3 +++ src/FontNames.c | 3 +++ src/GetColor.c | 4 ++++ src/LoadFont.c | 4 ++++ src/LookupCol.c | 6 ++++-- src/ParseCol.c | 5 ++++- src/QuExt.c | 5 +++++ src/SetFPath.c | 8 +++++++- src/SetHints.c | 7 +++++++ src/StNColor.c | 3 +++ src/StName.c | 7 ++++++- 12 files changed, 54 insertions(+), 7 deletions(-) diff --git a/src/Font.c b/src/Font.c index 09d2ae91..3f468e4b 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); @@ -662,8 +664,8 @@ int _XF86LoadQueryLocaleFont( if (!name) return 0; - l = strlen(name); - if (l < 2 || name[l - 1] != '*' || name[l - 2] != '-') + l = (int) strlen(name); + 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 f870e431..51b48e29 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 b78792d6..4dac4916 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 cd0eb9f6..512ac308 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 #endif +#include #include #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 f547976b..85735249 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 #endif +#include #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 f7f969f5..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 #endif +#include #include #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 = strlen (spec); LockDisplay(dpy); GetReq (LookupColor, req); req->cmap = cmap; diff --git a/src/ParseCol.c b/src/ParseCol.c index e997b1b8..180132dd 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 #endif +#include #include #include "Xlibint.h" #include "Xcmsint.h" @@ -46,7 +47,9 @@ XParseColor ( XcmsColor cmsColor; if (!spec) return(0); - n = strlen (spec); + n = (int) strlen (spec); + if (n >= USHRT_MAX) + return(0); if (*spec == '#') { /* * RGB diff --git a/src/QuExt.c b/src/QuExt.c index 4e230e77..d38a1572 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 #endif +#include +#include #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 ? strlen(name) : 0; diff --git a/src/SetFPath.c b/src/SetFPath.c index 60aaef01..3d8c50cb 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 +#include #endif #include "Xlibint.h" @@ -48,7 +49,12 @@ XSetFontPath ( GetReq (SetFontPath, req); req->nFonts = ndirs; for (i = 0; i < ndirs; i++) { - n += safestrlen (directories[i]) + 1; + 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 bc46498a..f3d727ec 100644 --- a/src/SetHints.c +++ b/src/SetHints.c @@ -49,6 +49,7 @@ SOFTWARE. #ifdef HAVE_CONFIG_H #include #endif +#include #include #include #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 8b821c3e..ba021958 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 #endif +#include #include #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 b4048bff..5a632d0c 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 #endif +#include #include #include @@ -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 ? 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 ? strlen(icon_name) : 0); -- 2.32.0