linux-kernel - [PATCH AUTOSEL 4.9 59/73] rslib: Fix handling of of caller provided syndrome

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: <20190715143629.10893-59-sashal@kernel.org>
Date:   Mon, 15 Jul 2019 10:36:15 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Ferdinand Blomqvist <ferdinand.blomqvist@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.9 59/73] rslib: Fix handling of of caller provided syndrome

From: Ferdinand Blomqvist <ferdinand.blomqvist@...il.com>

[ Upstream commit ef4d6a8556b637ad27c8c2a2cff1dda3da38e9a9 ]

Check if the syndrome provided by the caller is zero, and act
accordingly.

Signed-off-by: Ferdinand Blomqvist <ferdinand.blomqvist@...il.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lkml.kernel.org/r/20190620141039.9874-6-ferdinand.blomqvist@gmail.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 lib/reed_solomon/decode_rs.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/reed_solomon/decode_rs.c b/lib/reed_solomon/decode_rs.c
index 8eed0f9ac495..a5d313381539 100644
--- a/lib/reed_solomon/decode_rs.c
+++ b/lib/reed_solomon/decode_rs.c
@@ -42,8 +42,18 @@
 	BUG_ON(pad < 0 || pad >= nn);
 
 	/* Does the caller provide the syndrome ? */
-	if (s != NULL)
-		goto decode;
+	if (s != NULL) {
+		for (i = 0; i < nroots; i++) {
+			/* The syndrome is in index form,
+			 * so nn represents zero
+			 */
+			if (s[i] != nn)
+				goto decode;
+		}
+
+		/* syndrome is zero, no errors to correct  */
+		return 0;
+	}
 
 	/* form the syndromes; i.e., evaluate data(x) at roots of
 	 * g(x) */
-- 
2.20.1