Check the two popen() calls in noise_get_heavy for NULL.

git-svn-id: svn://svn.tartarus.org/sgt/putty@8411 cda61777-01e9-0310-a592-d414129be87e

diff --git a/unix/uxnoise.c b/unix/uxnoise.c
index b563f7c..7ebb9a5 100644 (file)
--- a/unix/uxnoise.c
+++ b/unix/uxnoise.c
@@ -4,6 +4,9 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
 #include <fcntl.h>
 #include <unistd.h>
 #include <sys/time.h>
@@ -47,19 +50,34 @@ void noise_get_heavy(void (*func) (void *, int))
     char buf[512];
     FILE *fp;
     int ret;
+    int got_dev_urandom = 0;
 
-    if (read_dev_urandom(buf, 32))
+    if (read_dev_urandom(buf, 32)) {
+       got_dev_urandom = 1;
        func(buf, 32);
+    }
 
     fp = popen("ps -axu 2>/dev/null", "r");
-    while ( (ret = fread(buf, 1, sizeof(buf), fp)) > 0)
-       func(buf, ret);
-    pclose(fp);
+    if (fp) {
+       while ( (ret = fread(buf, 1, sizeof(buf), fp)) > 0)
+           func(buf, ret);
+       pclose(fp);
+    } else if (!got_dev_urandom) {
+       fprintf(stderr, "popen: %s\n"
+               "Unable to access fallback entropy source\n", strerror(errno));
+       exit(1);
+    }
 
     fp = popen("ls -al /tmp 2>/dev/null", "r");
-    while ( (ret = fread(buf, 1, sizeof(buf), fp)) > 0)
-       func(buf, ret);
-    pclose(fp);
+    if (fp) {
+       while ( (ret = fread(buf, 1, sizeof(buf), fp)) > 0)
+           func(buf, ret);
+       pclose(fp);
+    } else if (!got_dev_urandom) {
+       fprintf(stderr, "popen: %s\n"
+               "Unable to access fallback entropy source\n", strerror(errno));
+       exit(1);
+    }
 
     read_random_seed(func);
     random_save_seed();