1 files changed, 20 insertions, 2 deletions

diff --git a/crypt.cpp b/crypt.cpp
index 5f0d01d..f59a704 100644
--- a/crypt.cpp
+++ b/crypt.cpp
@@ -17,25 +17,37 @@ extern char *outfname;
 
 struct rsakey_t
 {
-    long unsigned e, d, n;
+    unsigned long e, d, n;
+    bool valid_rsa_tag;
 };
 
 /* parse pubkey xml file */
 struct rsakey_t parse_key(FILE *file)
 {
     struct rsakey_t key = { 0, 0, 0};
+    key.valid_rsa_tag = false;
 
     /* used for line reading */
     size_t line_sz = 0;
     char *line = NULL;
 
+    bool rsa_opening_tag = false;
+    bool rsa_closing_tag = false;
+
     while (getline(&line, &line_sz, file) != -1)
     {
+        if (strcmp(line, "<rsakey>\n") == 0)
+            rsa_opening_tag = true;
         sscanf(line, "\t<dvalue>%lu</dvalue>\n", &key.d);
         sscanf(line, "\t<evalue>%lu</evalue>\n", &key.e);
         sscanf(line, "\t<nvalue>%lu</nvalue>\n", &key.n);
+        if (strcmp(line, "</rsakey>\n") == 0)
+            rsa_closing_tag = true;
     }
 
+    if (rsa_opening_tag && rsa_closing_tag)
+        key.valid_rsa_tag = true;
+
     if (line)
         free(line);
 
@@ -74,7 +86,13 @@ int main(int argc, char **argv)
     int mode = -1;
     struct rsakey_t key = parse_key(keyfname_fl);
 
-    if (key.d == 0 && key.e && key.n)
+    if (!key.valid_rsa_tag)
+    {
+        fprintf(stderr, "invalid key or invalid xml\n");
+        exit(EXIT_FAILURE);
+    }
+
+    else if (key.d == 0 && key.e && key.n)
     {
         cout << "public key (" << key.e << ", " << key.n
              << ") detected, will perform encryption" << endl;