1 files changed, 70 insertions, 0 deletions
diff --git a/contrib/pam_modules/pam_passwdqc/concat.c b/contrib/pam_modules/pam_passwdqc/concat.c
new file mode 100644
index 000000000000..de1f75dcbb51
--- /dev/null
+++ b/contrib/pam_modules/pam_passwdqc/concat.c
@@ -0,0 +1,70 @@
+/*
+ * concat() - allocate memory and safely concatenate strings in portable C
+ * (and C++ if you like).
+ *
+ * This code deals gracefully with potential integer overflows (perhaps when
+ * input strings are maliciously long), as well as with input strings changing
+ * from under it (perhaps because of misbehavior of another thread).  It does
+ * not depend on non-portable functions such as snprintf() and asprintf().
+ *
+ * Written by Solar Designer <solar at openwall.com> and placed in the
+ * public domain.
+ */
+
+#include <string.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <limits.h>
+#include "concat.h"
+
+char *concat(const char *s1, ...)
+{
+	va_list args;
+	const char *s;
+	char *p, *result;
+	size_t l, m, n;
+
+	m = n = strlen(s1);
+	va_start(args, s1);
+	while ((s = va_arg(args, char *))) {
+		l = strlen(s);
+		if ((m += l) < l)
+			break;
+	}
+	va_end(args);
+	if (s || m >= INT_MAX)
+		return NULL;
+
+	result = (char *)malloc(m + 1);
+	if (!result)
+		return NULL;
+
+	memcpy(p = result, s1, n);
+	p += n;
+	va_start(args, s1);
+	while ((s = va_arg(args, char *))) {
+		l = strlen(s);
+		if ((n += l) < l || n > m)
+			break;
+		memcpy(p, s, l);
+		p += l;
+	}
+	va_end(args);
+	if (s || m != n || p != result + n) {
+		free(result);
+		return NULL;
+	}
+
+	*p = 0;
+	return result;
+}
+
+#ifdef TEST
+#include <stdio.h>
+
+int main(int argc, char **argv)
+{
+	puts(concat(argv[0], argv[1], argv[2], argv[3], NULL));
+	return 0;
+}
+#endif