linux-kernel - [PATCH v2 5.4 regression fix] x86/boot: Provide memzero

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-next>] [day] [month] [year] [list]

Message-Id: <20191007134724.4019-1-hdegoede@redhat.com>
Date:   Mon,  7 Oct 2019 15:47:24 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>
Cc:     Hans de Goede <hdegoede@...hat.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        linux-crypto@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org, Arvind Sankar <nivedita@...m.mit.edu>
Subject: [PATCH v2 5.4 regression fix] x86/boot: Provide memzero_explicit

The purgatory code now uses the shared lib/crypto/sha256.c sha256
implementation. This needs memzero_explicit, implement this.

Reported-by: Arvind Sankar <nivedita@...m.mit.edu>
Fixes: 906a4bb97f5d ("crypto: sha256 - Use get/put_unaligned_be32 to get input, memzero_explicit")
Signed-off-by: Hans de Goede <hdegoede@...hat.com>
---
Changes in v2:
- Add barrier_data() call after the memset, making the function really
  explicit. Using barrier_data() works fine in the purgatory (build)
  environment.
---
 arch/x86/boot/compressed/string.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c
index 81fc1eaa3229..654a7164a702 100644
--- a/arch/x86/boot/compressed/string.c
+++ b/arch/x86/boot/compressed/string.c
@@ -50,6 +50,12 @@ void *memset(void *s, int c, size_t n)
 	return s;
 }
 
+void memzero_explicit(void *s, size_t count)
+{
+	memset(s, 0, count);
+	barrier_data(s);
+}
+
 void *memmove(void *dest, const void *src, size_t n)
 {
 	unsigned char *d = dest;
-- 
2.23.0