From 3ba74ad02d3a20d50c068faa02797fafba105508 Mon Sep 17 00:00:00 2001
From: Stephen Gallagher <sgallagh@redhat.com>
Date: Wed, 25 Aug 2010 10:44:14 -0400
Subject: Add utility function sss_strnlen()

This is useful for guaranteeing the size of an input buffer.
---
 src/sss_client/common.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

(limited to 'src/sss_client/common.c')

diff --git a/src/sss_client/common.c b/src/sss_client/common.c
index 6b79c7830..3bfa89281 100644
--- a/src/sss_client/common.c
+++ b/src/sss_client/common.c
@@ -761,3 +761,32 @@ const char *ssscli_err2string(int err)
 
     return _("Unexpected error while looking for an error description");
 }
+
+/* Return strlen(str) or maxlen, whichever is shorter
+ * Returns EINVAL if str is NULL, EFBIG if str is longer than maxlen
+ * _len will return the result
+ *
+ * This function is useful for preventing buffer overflow attacks.
+ */
+errno_t sss_strnlen(const char *str, size_t maxlen, size_t *len)
+{
+    if (!str) {
+        return EINVAL;
+    }
+
+#if defined __USE_GNU
+    *len = strnlen(str, maxlen);
+#else
+    *len = 0;
+    while (*len < maxlen) {
+        if (str[*len] == '\0') break;
+        len++;
+    }
+#endif
+
+    if (*len == maxlen && str[*len] != '\0') {
+        return EFBIG;
+    }
+
+    return 0;
+}
-- 
cgit