[PATCH] hamradio: dmascc: avoid -Wformat-overflow warning

From: Arnd Bergmann
Date: Wed Jul 26 2017 - 03:56:03 EST


gcc warns that the device name might overflow:

drivers/net/hamradio/dmascc.c: In function 'dmascc_init':
drivers/net/hamradio/dmascc.c:584:22: error: 'sprintf' may write a terminating nul past the end of the destination [-Werror=format-overflow=]
sprintf(dev->name, "dmascc%i", 2 * n + i);
drivers/net/hamradio/dmascc.c:584:3: note: 'sprintf' output between 8 and 17 bytes into a destination of size 16
sprintf(dev->name, "dmascc%i", 2 * n + i);

>From the static data in this file, I can tell that the index is
strictly limited to 16, so it won't overflow. This simply changes
the sprintf() to snprintf(), which is a good idea in general,
and shuts up this warning.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
I ran into this for the first time today on linux-next randconfig
builds, but couldn't find an obvious commit that introduced it.

I guess it's just a very rare randconfig warning, so this can go
into net-next rather than net fixes.
---
drivers/net/hamradio/dmascc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/hamradio/dmascc.c b/drivers/net/hamradio/dmascc.c
index dec6b76bc0fb..cde41200f40a 100644
--- a/drivers/net/hamradio/dmascc.c
+++ b/drivers/net/hamradio/dmascc.c
@@ -581,7 +581,7 @@ static int __init setup_adapter(int card_base, int type, int n)
priv->param.dma = -1;
INIT_WORK(&priv->rx_work, rx_bh);
dev->ml_priv = priv;
- sprintf(dev->name, "dmascc%i", 2 * n + i);
+ snprintf(dev->name, sizeof(dev->name), "dmascc%i", 2 * n + i);
dev->base_addr = card_base;
dev->irq = irq;
dev->netdev_ops = &scc_netdev_ops;
--
2.9.0