* mdocml: Security fix: Validate the name of the file to show before
@ 2014-07-19 11:35 schwarze
0 siblings, 0 replies; only message in thread
From: schwarze @ 2014-07-19 11:35 UTC (permalink / raw)
To: source
Log Message:
-----------
Security fix:
Validate the name of the file to show before opening it.
Only allow relative filenames starting with "man" or "cat"
and containing neither "/.." nor "../".
While here, correct the condition discarding an initial "./".
Vulnerability found by Sebastien Marie <semarie-openbsd at latrappe dot fr>.
Many thanks for sending a patch; however, i did not use it but made the
checks even stricter.
Modified Files:
--------------
mdocml:
cgi.c
Revision Data
-------------
Index: cgi.c
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/cgi.c,v
retrieving revision 1.75
retrieving revision 1.76
diff -Lcgi.c -Lcgi.c -u -p -r1.75 -r1.76
--- cgi.c
+++ cgi.c
@@ -466,6 +466,17 @@ resp_searchform(const struct req *req)
puts("<!-- End search form. //-->");
}
+static int
+validate_filename(const char *file)
+{
+
+ if ('.' == file[0] && '/' == file[1])
+ file += 2;
+
+ return ( ! (strstr(file, "../") || strstr(file, "/..") ||
+ (strncmp(file, "man", 3) && strncmp(file, "cat", 3))));
+}
+
static void
pg_index(const struct req *req)
{
@@ -523,6 +534,15 @@ pg_searchres(const struct req *req, stru
int prio, priouse;
char sec;
+ for (i = 0; i < sz; i++) {
+ if (validate_filename(r[i].file))
+ continue;
+ fprintf(stderr, "invalid filename %s in %s database\n",
+ r[i].file, req->q.manpath);
+ pg_error_internal();
+ return;
+ }
+
if (1 == sz) {
/*
* If we have just one result, then jump there now
@@ -777,7 +797,8 @@ format(const struct req *req, const char
static void
resp_show(const struct req *req, const char *file)
{
- if ('.' == file[0] || '/' == file[1])
+
+ if ('.' == file[0] && '/' == file[1])
file += 2;
if ('c' == *file)
@@ -807,6 +828,12 @@ pg_show(const struct req *req, const cha
if (-1 == chdir(path)) {
pg_error_badrequest(
"You specified an invalid manpath.");
+ return;
+ }
+
+ if ( ! validate_filename(sub)) {
+ pg_error_badrequest(
+ "You specified an invalid manual file.");
return;
}
--
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