[PATCH 2/2] lib/bch: fix signed shift overflow in build_mod8_tables

[Josh Law <objecting@objecting.org>]

Cast loop variable to unsigned int before left-shifting to avoid
undefined behavior when i >= 128 and b == 3 (i << 24 overflows
signed int).

Signed-off-by: Josh Law <objecting@objecting.org>
---
 lib/bch.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/bch.c b/lib/bch.c
index ef733f08082f..c991c71c4cbd 100644
--- a/lib/bch.c
+++ b/lib/bch.c
@@ -1116,7 +1116,7 @@ static void build_mod8_tables(struct bch_control *bch, const uint32_t *g)
 		for (b = 0; b < 4; b++) {
 			/* we want to compute (p(X).X^(8*b+deg(g))) mod g(X) */
 			tab = bch->mod8_tab + (b*256+i)*l;
-			data = i << (8*b);
+			data = (unsigned int)i << (8*b);
 			while (data) {
 				d = deg(data);
 				/* subtract X^d.g(X) from p(X).X^(8*b+deg(g)) */
-- 
2.34.1