From b53f27e4fa0d0e72d897830cc4f3f83d2a25d952 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Wed, 20 Apr 2016 15:46:23 -0700
Subject: [PATCH] string_helpers: add kstrdup_quotable
Handle allocating and escaping a string safe for logging.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
---
include/linux/string_helpers.h | 2 ++
lib/string_helpers.c | 28 ++++++++++++++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index dabe643eb5fad..9de228af00c18 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -68,4 +68,6 @@ static inline int string_escape_str_any_np(const char *src, char *dst,
return string_escape_str(src, dst, sz, ESCAPE_ANY_NP, only);
}
+char *kstrdup_quotable(const char *src, gfp_t gfp);
+
#endif
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 5c88204b6f1f1..aa00c9f989eec 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -10,6 +10,7 @@
#include <linux/export.h>
#include <linux/ctype.h>
#include <linux/errno.h>
+#include <linux/slab.h>
#include <linux/string.h>
#include <linux/string_helpers.h>
@@ -534,3 +535,30 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
return p - dst;
}
EXPORT_SYMBOL(string_escape_mem);
+
+/*
+ * Return an allocated string that has been escaped of special characters
+ * and double quotes, making it safe to log in quotes.
+ */
+char *kstrdup_quotable(const char *src, gfp_t gfp)
+{
+ size_t slen, dlen;
+ char *dst;
+ const int flags = ESCAPE_HEX;
+ const char esc[] = "\f\n\r\t\v\a\e\\\"";
+
+ if (!src)
+ return NULL;
+ slen = strlen(src);
+
+ dlen = string_escape_mem(src, slen, NULL, 0, flags, esc);
+ dst = kmalloc(dlen + 1, gfp);
+ if (!dst)
+ return NULL;
+
+ WARN_ON(string_escape_mem(src, slen, dst, dlen, flags, esc) != dlen);
+ dst[dlen] = '\0';
+
+ return dst;
+}
+EXPORT_SYMBOL_GPL(kstrdup_quotable);
--
GitLab