netdev - [PATCH net] lib: packing: fix shift wrapping in bit

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Message-ID: <Y5B3sAcS6qKSt+lS@kili>
Date:   Wed, 7 Dec 2022 14:23:28 +0300
From:   Dan Carpenter <error27@...il.com>
To:     Vladimir Oltean <olteanv@...il.com>
Cc:     "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: [PATCH net] lib: packing: fix shift wrapping in bit_reverse()

The bit_reverse() function is clearly supposed to be able to handle
64 bit values, but the types for "(1 << i)" and "bit << (width - i - 1)"
are not enough to handle more than 32 bits.

Fixes: 554aae35007e ("lib: Add support for generic packing operations")
Signed-off-by: Dan Carpenter <error27@...il.com>
---
 lib/packing.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/packing.c b/lib/packing.c
index 9a72f4bbf0e2..9d7418052f5a 100644
--- a/lib/packing.c
+++ b/lib/packing.c
@@ -32,12 +32,11 @@ static int get_reverse_lsw32_offset(int offset, size_t len)
 static u64 bit_reverse(u64 val, unsigned int width)
 {
 	u64 new_val = 0;
-	unsigned int bit;
 	unsigned int i;
 
 	for (i = 0; i < width; i++) {
-		bit = (val & (1 << i)) != 0;
-		new_val |= (bit << (width - i - 1));
+		if (val & BIT_ULL(1))
+			new_val |= BIT_ULL(width - i - 1);
 	}
 	return new_val;
 }
-- 
2.35.1