CVE-2014-0210: unvalidated lengths when reading replies from font server from xorg/lib/libXfont commit cbb64aef35960b2882be721f4b8fbaa0fb649d12

Functions to handle replies to font server requests were casting replies
from the generic form to reply specific structs without first checking
that the reply was at least as long as the struct being cast to.

1 files changed, 38 insertions, 6 deletions

diff --git a/nx-X11/lib/font/fc/fserve.c b/nx-X11/lib/font/fc/fserve.c
index c159b2b46..ca10aa4ad 100644
--- a/nx-X11/lib/font/fc/fserve.c
+++ b/nx-X11/lib/font/fc/fserve.c
@@ -94,6 +94,12 @@ in this Software without prior written authorization from The Open Group.
 			     (pci)->descent || \
 			     (pci)->characterWidth)
 
+/*
+ * SIZEOF(r) is in bytes, length fields in the protocol are in 32-bit words,
+ * so this converts for doing size comparisons.
+ */
+#define LENGTHOF(r)	(SIZEOF(r) >> 2)
+
 extern void ErrorF(const char *f, ...);
 
 static int fs_read_glyphs ( FontPathElementPtr fpe, FSBlockDataPtr blockrec );
@@ -209,9 +215,22 @@ _fs_add_rep_log (FSFpePtr conn, fsGenericReply *rep)
 		 rep->sequenceNumber,
 		 conn->reqbuffer[i].opcode);
 }
+
+#define _fs_reply_failed(rep, name, op) do {                            \
+    if (rep) {                                                          \
+        if (rep->type == FS_Error)                                      \
+            fprintf (stderr, "Error: %d Request: %s\n",                 \
+                     ((fsError *)rep)->request, #name);                 \
+        else                                                            \
+            fprintf (stderr, "Bad Length for %s Reply: %d %s %d\n",     \
+                     #name, rep->length, op, LENGTHOF(name));           \
+    }                                                                   \
+} while (0)
+
 #else
 #define _fs_add_req_log(conn,op)    ((conn)->current_seq++)
 #define _fs_add_rep_log(conn,rep)
+#define _fs_reply_failed(rep,name,op)
 #endif
 
 static Bool
@@ -693,13 +712,15 @@ fs_read_open_font(FontPathElementPtr fpe, FSBlockDataPtr blockrec)
     int			    ret;
 
     rep = (fsOpenBitmapFontReply *) fs_get_reply (conn, &ret);
-    if (!rep || rep->type == FS_Error)
+    if (!rep || rep->type == FS_Error ||
+	(rep->length != LENGTHOF(fsOpenBitmapFontReply)))
     {
 	if (ret == FSIO_BLOCK)
 	    return StillWorking;
 	if (rep)
 	    _fs_done_read (conn, rep->length << 2);
 	fs_cleanup_bfont (bfont);
+	_fs_reply_failed (rep, fsOpenBitmapFontReply, "!=");
 	return BadFontName;
     }
 	   
@@ -835,13 +856,15 @@ fs_read_query_info(FontPathElementPtr fpe, FSBlockDataPtr blockrec)
     int			ret;
 
     rep = (fsQueryXInfoReply *) fs_get_reply (conn, &ret);
-    if (!rep || rep->type == FS_Error)
+    if (!rep || rep->type == FS_Error ||
+	(rep->length < LENGTHOF(fsQueryXInfoReply)))
     {
 	if (ret == FSIO_BLOCK)
 	    return StillWorking;
 	if (rep)
 	    _fs_done_read (conn, rep->length << 2);
 	fs_cleanup_bfont (bfont);
+	_fs_reply_failed (rep, fsQueryXInfoReply, "<");
 	return BadFontName;
     }
 	
@@ -962,13 +985,15 @@ fs_read_extent_info(FontPathElementPtr fpe, FSBlockDataPtr blockrec)
     FontInfoRec		    *fi = &bfont->pfont->info;
 
     rep = (fsQueryXExtents16Reply *) fs_get_reply (conn, &ret);
-    if (!rep || rep->type == FS_Error)
+    if (!rep || rep->type == FS_Error ||
+	(rep->length < LENGTHOF(fsQueryXExtents16Reply)))
     {
 	if (ret == FSIO_BLOCK)
 	    return StillWorking;
 	if (rep)
 	    _fs_done_read (conn, rep->length << 2);
 	fs_cleanup_bfont (bfont);
+	_fs_reply_failed (rep, fsQueryXExtents16Reply, "<");
 	return BadFontName;
     }
 	
@@ -1833,13 +1858,15 @@ fs_read_glyphs(FontPathElementPtr fpe, FSBlockDataPtr blockrec)
     unsigned long	    minchar, maxchar;
 
     rep = (fsQueryXBitmaps16Reply *) fs_get_reply (conn, &ret);
-    if (!rep || rep->type == FS_Error)
+    if (!rep || rep->type == FS_Error ||
+	(rep->length < LENGTHOF(fsQueryXBitmaps16Reply)))
     {
 	if (ret == FSIO_BLOCK)
 	    return StillWorking;
 	if (rep)
 	    _fs_done_read (conn, rep->length << 2);
 	err = AllocError;
+	_fs_reply_failed (rep, fsQueryXBitmaps16Reply, "<");
 	goto bail;
     }
 
@@ -2243,12 +2270,14 @@ fs_read_list(FontPathElementPtr fpe, FSBlockDataPtr blockrec)
     int			err;
 
     rep = (fsListFontsReply *) fs_get_reply (conn, &ret);
-    if (!rep || rep->type == FS_Error)
+    if (!rep || rep->type == FS_Error ||
+	(rep->length < LENGTHOF(fsListFontsReply)))
     {
 	if (ret == FSIO_BLOCK)
 	    return StillWorking;
 	if (rep)
 	    _fs_done_read (conn, rep->length << 2);
+	_fs_reply_failed (rep, fsListFontsReply, "<");
 	return AllocError;
     }
     data = (char *) rep + SIZEOF (fsListFontsReply);
@@ -2366,12 +2395,15 @@ fs_read_list_info(FontPathElementPtr fpe, FSBlockDataPtr blockrec)
     _fs_free_props (&binfo->info);
 
     rep = (fsListFontsWithXInfoReply *) fs_get_reply (conn, &ret);
-	if (!rep || rep->type == FS_Error)
+    if (!rep || rep->type == FS_Error ||
+       ((rep->nameLength != 0) &&
+        (rep->length < LENGTHOF(fsListFontsWithXInfoReply))))
     {
 	if (ret == FSIO_BLOCK)
 	    return StillWorking;
 	binfo->status = FS_LFWI_FINISHED;
 	err = AllocError;
+	_fs_reply_failed (rep, fsListFontsWithXInfoReply, "<");
 	goto done;
     }
     /*