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Message-ID: <20111106200911.GC13652@netbsd.org>
Date: Sun, 6 Nov 2011 20:09:11 +0000
From: David Holland <dholland-oss-security@...bsd.org>
To: oss-security@...ts.openwall.com
Subject: caml-light insecure temporary files

I apologize for sending this out on a weekend... but I found out it
accidentally got broadcast to one of our mailing lists so there's
nothing much to be gained from waiting. And besides, it's neither
particularly critical nor of particularly broad interest.

Anyway.

I don't know if anyone besides us still ships caml-light; it is long
dead upstream and obsoleted by ocaml. AFAICT neither Debian nor Red
Hat does. But just in case: it uses mktemp() insecurely, and also does
unsafe things in /tmp during make install.

Patches follow; reference URL (including copies of the patches) is
http://gnats.netbsd.org/45558.

I'm not sure it's worth allocating a CVE number for this if it turns
out nobody else ships it.

--- src/yacc/main.c~	1995-06-07 09:34:32.000000000 -0400
+++ src/yacc/main.c
@@ -1,4 +1,5 @@
 #include <signal.h>
+#include <stdlib.h> /* for mkstemp(), getenv() */
 #include "defs.h"
 
 char dflag;
@@ -31,6 +32,11 @@ char *text_file_name;
 char *union_file_name;
 char *verbose_file_name;
 
+static int action_fd = -1;
+static int entry_fd = -1;
+static int text_fd = -1;
+static int union_fd = -1;
+
 FILE *action_file;	/*  a temp file, used to save actions associated    */
 			/*  with rules until the parser is written	    */
 FILE *entry_file;
@@ -69,9 +75,6 @@ char  *rassoc;
 short **derives;
 char *nullable;
 
-extern char *mktemp();
-extern char *getenv();
-
 
 done(k)
 int k;
@@ -276,12 +279,21 @@ create_file_names()
     union_file_name[len + 5] = 'u';
 
 #ifndef NO_UNIX
-    mktemp(action_file_name);
-    mktemp(entry_file_name);
-    mktemp(text_file_name);
-    mktemp(union_file_name);
+    action_fd = mkstemp(action_file_name);
+    entry_fd = mkstemp(entry_file_name);
+    text_fd = mkstemp(text_file_name);
+    union_fd = mkstemp(union_file_name);
 #endif
 
+    if (action_fd < 0)
+	open_error(action_file_name);
+    if (entry_fd < 0)
+	open_error(entry_file_name);
+    if (text_fd < 0)
+	open_error(text_file_name);
+    if (union_fd < 0)
+	open_error(union_file_name);
+
     len = strlen(file_prefix);
 
     output_file_name = MALLOC(len + 7);
@@ -321,15 +333,15 @@ open_files()
 	    open_error(input_file_name);
     }
 
-    action_file = fopen(action_file_name, "w");
+    action_file = fdopen(action_fd, "w");
     if (action_file == 0)
 	open_error(action_file_name);
 
-    entry_file = fopen(entry_file_name, "w");
+    entry_file = fdopen(entry_fd, "w");
     if (entry_file == 0)
 	open_error(entry_file_name);
 
-    text_file = fopen(text_file_name, "w");
+    text_file = fdopen(text_fd, "w");
     if (text_file == 0)
 	open_error(text_file_name);
 
@@ -345,7 +357,7 @@ open_files()
 	defines_file = fopen(defines_file_name, "w");
 	if (defines_file == 0)
 	    open_error(defines_file_name);
-	union_file = fopen(union_file_name, "w");
+	union_file = fdopen(union_fd, "w");
 	if (union_file ==  0)
 	    open_error(union_file_name);
     }

--- src/launch/Makefile~	1995-02-22 04:33:26.000000000 -0500
+++ src/launch/Makefile
@@ -10,19 +10,20 @@ all: camlc camllight camlmktop camlexec 
 # Also, "make install" is done with root permissions, meaning that we don't
 # have write permission in the current directory if NFS-mounted...
 
+#	(echo "#!$(BINDIR)/camlrun"; \
+#	 echo "exit 2"; \
+#	 cat testprog) > /tmp/testscr
+#	chmod a+x /tmp/testscr
+#	sh -c 'if sh -c /tmp/testscr 2>/dev/null; \
+#               then echo "#!$(BINDIR)/camlrun" > $(LIBDIR)/header; \
+#               else cp camlexec $(LIBDIR)/header; \
+#               fi'
+#	rm -f /tmp/testscr
 install:
-	(echo "#!$(BINDIR)/camlrun"; \
-	 echo "exit 2"; \
-	 cat testprog) > /tmp/testscr
-	chmod a+x /tmp/testscr
-	sh -c 'if sh -c /tmp/testscr 2>/dev/null; \
-               then echo "#!$(BINDIR)/camlrun" > $(LIBDIR)/header; \
-               else cp camlexec $(LIBDIR)/header; \
-               fi'
-	rm -f /tmp/testscr
+	echo "#!$(BINDIR)/camlrun" > $(DESTDIR)$(LIBDIR)/header
 	for script in camlc camllight camlmktop; do \
-	  cp $$script $(BINDIR)/$$script; \
-	  chmod a+x $(BINDIR)/$$script; \
+	  cp $$script $(DESTDIR)$(BINDIR)/$$script; \
+	  chmod a+x $(DESTDIR)$(BINDIR)/$$script; \
 	done
 
 SEDCOMMANDS=\


-- 
David A. Holland
dholland@...bsd.org

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