From ef4d6a8556b637ad27c8c2a2cff1dda3da38e9a9 Mon Sep 17 00:00:00 2001
From: Ferdinand Blomqvist <ferdinand.blomqvist@gmail.com>
Date: Thu, 20 Jun 2019 17:10:37 +0300
Subject: [PATCH] rslib: Fix handling of of caller provided syndrome
Git-commit: ef4d6a8556b637ad27c8c2a2cff1dda3da38e9a9
Patch-mainline: v5.3-rc1
References: bsc#1051510
Check if the syndrome provided by the caller is zero, and act
accordingly.
Signed-off-by: Ferdinand Blomqvist <ferdinand.blomqvist@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190620141039.9874-6-ferdinand.blomqvist@gmail.com
Acked-by: Takashi Iwai <tiwai@suse.de>
---
lib/reed_solomon/decode_rs.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--- 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) */