linux-kernel - [PATCH][V2] dmaengine: coh901318: fix integer overflow when shifting more than 32 places

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20160929181438.14374-1-colin.king@canonical.com>
Date:   Thu, 29 Sep 2016 19:14:38 +0100
From:   Colin King <colin.king@...onical.com>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Vinod Koul <vinod.koul@...el.com>,
        linux-arm-kernel@...ts.infradead.org, dmaengine@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH][V2] dmaengine: coh901318: fix integer overflow when shifting more than 32 places

From: Colin Ian King <colin.king@...onical.com>

Currently U300_DMA_CHANNELS is set to 40, meaning that the shift of 1 can
be more than 32 places, which leads to a 32 bit integer overflow. Fix this
by using 1ULL instead of 1 before shifting it.  Also add braces on the
for-loop to keep with coding style conventions.

Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/dma/coh901318.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c
index 2835f3e..74794c9 100644
--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -1352,9 +1352,10 @@ static ssize_t coh901318_debugfs_read(struct file *file, char __user *buf,
 
 	tmp += sprintf(tmp, "DMA -- enabled dma channels\n");
 
-	for (i = 0; i < U300_DMA_CHANNELS; i++)
-		if (started_channels & (1 << i))
+	for (i = 0; i < U300_DMA_CHANNELS; i++) {
+		if (started_channels & (1ULL << i))
 			tmp += sprintf(tmp, "channel %d\n", i);
+	}
 
 	tmp += sprintf(tmp, "Pool alloc nbr %d\n", pool_count);
 
-- 
2.9.3