Unbounded recursion in GetDatabase() when parsing include files [CVE-2013-2004 1/2]

GetIncludeFile() can call GetDatabase() which can call GetIncludeFile() which can call GetDatabase() which can call GetIncludeFile() .... eventually causing recursive stack overflow and crash. Easily reproduced with a resource file that #includes itself. Limit is set to a include depth of 100 files, which should be enough for all known use cases, but could be adjusted later if necessary. Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com> Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com> Reviewed-by: Matthieu Herrb <matthieu.herrb@laas.fr> Signed-off-by: Julien Cristau <jcristau@debian.org> Backported-to-NX-by: Ulrich Sibiller <uli42@gmx.de>

Unbounded recursion in GetDatabase() when parsing include files [CVE-2013-2004 1/2]
bddfee4a · Alan Coopersmith · Ulrich Sibiller · dbc11719 · bddfee4a
Commit bddfee4a authored Mar 02, 2013 by Alan Coopersmith Committed by Ulrich Sibiller Oct 12, 2016
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Showing with 15 additions and 9 deletions

Xrm.c nx-X11/lib/X11/Xrm.c +15 -9

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--- a/nx-X11/lib/X11/Xrm.c
+++ b/nx-X11/lib/X11/Xrm.c
@@ -1087,13 +1087,15 @@ static void GetIncludeFile(
    XrmDatabase db,
    _Xconst char *base,
    _Xconst char *fname,
-    int fnamelen);
+    int fnamelen,
+    int depth);

 static void GetDatabase(
    XrmDatabase db,
    _Xconst register char *str,
    _Xconst char *filename,
-    Bool doall)
+    Bool doall,
+    int depth)
 {
    char *rhs;
    char *lhs, lhs_s[DEF_BUFF_SIZE];
@@ -1203,7 +1205,8 @@ static void GetDatabase(
 		    } while (c != '"' && !is_EOL(bits));
 		    /* must have an ending " */
 		    if (c == '"')
-			GetIncludeFile(db, filename, fname, str - len - fname);
+			GetIncludeFile(db, filename, fname, str - len - fname,
+			    depth);
 		}
 	    }
 	    /* spin to next newline */
@@ -1544,7 +1547,7 @@ XrmPutLineResource(
 {
    if (!*pdb) *pdb = NewDatabase();
    _XLockMutex(&(*pdb)->linfo);
-    GetDatabase(*pdb, line, (char *)NULL, False);
+    GetDatabase(*pdb, line, (char *)NULL, False, 0);
    _XUnlockMutex(&(*pdb)->linfo);
 }

@@ -1556,7 +1559,7 @@ XrmGetStringDatabase(

    db = NewDatabase();
    _XLockMutex(&db->linfo);
-    GetDatabase(db, data, (char *)NULL, True);
+    GetDatabase(db, data, (char *)NULL, True, 0);
    _XUnlockMutex(&db->linfo);
    return db;
 }
@@ -1633,7 +1636,8 @@ GetIncludeFile(
    XrmDatabase db,
    _Xconst char *base,
    _Xconst char *fname,
-    int fnamelen)
+    int fnamelen,
+    int depth)
 {
    int len;
    char *str;
@@ -1641,6 +1645,8 @@ GetIncludeFile(

    if (fnamelen <= 0 || fnamelen >= BUFSIZ)
 	return;
+    if (depth >= MAXDBDEPTH)
+	return;
    if (*fname != '/' && base && (str = strrchr(base, '/'))) {
 	len = str - base + 1;
 	if (len + fnamelen >= BUFSIZ)
@@ -1654,7 +1660,7 @@ GetIncludeFile(
    }
    if (!(str = ReadInFile(realfname)))
 	return;
-    GetDatabase(db, str, realfname, True);
+    GetDatabase(db, str, realfname, True, depth + 1);
    Xfree(str);
 }

@@ -1670,7 +1676,7 @@ XrmGetFileDatabase(

    db = NewDatabase();
    _XLockMutex(&db->linfo);
-    GetDatabase(db, str, filename, True);
+    GetDatabase(db, str, filename, True, 0);
    _XUnlockMutex(&db->linfo);
    Xfree(str);
    return db;
@@ -1694,7 +1700,7 @@ XrmCombineFileDatabase(
    } else
 	db = NewDatabase();
    _XLockMutex(&db->linfo);
-    GetDatabase(db, str, filename, True);
+    GetDatabase(db, str, filename, True, 0);
    _XUnlockMutex(&db->linfo);
    Xfree(str);
    if (!override)