linux-kernel - [RFC PATCH 3/7] kernel.h: implement fmtmatch() wrapper around fmtcheck()

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181026232409.16100-4-linux@rasmusvillemoes.dk>
Date:   Sat, 27 Oct 2018 01:24:05 +0200
From:   Rasmus Villemoes <linux@...musvillemoes.dk>
To:     Kees Cook <keescook@...omium.org>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org,
        Rasmus Villemoes <linux@...musvillemoes.dk>
Subject: [RFC PATCH 3/7] kernel.h: implement fmtmatch() wrapper around fmtcheck()

Some users may prefer to check a "user-supplied" string upfront and
return EINVAL rather than using the the template as a fallback for
printf'ing later. fmtmatch() is simply a shorthand for

  fmtcheck(a, b, c | FMTCHECK_SILENT) == a.

Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk>
---
 include/linux/kernel.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 8e9154e100c3..c2b710426227 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -507,11 +507,18 @@ _fmtcheck(const char *fmt, const char *tmpl, unsigned flags)
 	return fmt;
 }
 #endif
+
+static inline bool
+_fmtmatch(const char *fmt, const char *tmpl, unsigned flags)
+{
+       return _fmtcheck(fmt, tmpl, flags | FMTCHECK_SILENT) == fmt;
+}
 /*
  * Use of fmtcheck is pointless if the template is not a string
  * literal, so try to enforce that.
  */
 #define fmtcheck(fmt, tmpl, flags) _fmtcheck(fmt, "" tmpl "", flags)
+#define fmtmatch(fmt, tmpl, flags) _fmtmatch(fmt, "" tmpl "", flags)
 
 extern __scanf(2, 3)
 int sscanf(const char *, const char *, ...);
-- 
2.19.1.6.gbde171bbf5