Messages in this thread Patch in this message | | | Date | Mon, 30 Jul 2007 00:04:46 +0530 (IST) | From | Satyam Sharma <> | Subject | Re: [PATCH] sb1000: prevent a potential NULL pointer dereference in sb1000_dev_ioctl() |
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> On Sun, 29 Jul 2007, Domen Puncer wrote: > > > On 29/07/07 00:02 +0200, Jesper Juhl wrote: > > > Hi, > > > > > > Here's a small patch, prompted by a find by the Coverity checker, > > > that removes a potential NULL pointer dereference from > > > drivers/net/sb1000.c::sb1000_dev_ioctl(). > > > The checker spotted that we do a NULL test of 'dev', yet we > > > dereference the pointer prior to that check. > > > This patch simply moves the dereference after the NULL test. > > > > But... it can't be called without a valid 'dev', no? > > A quick 'grep do_ioctl net/' confirms that all calls are in > > the form of 'dev->do_ioctl(dev, ...'. > > Yup, I think so too ... > > > > > @@ -991,11 +991,13 @@ static int sb1000_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) > > > short PID[4]; > > > int ioaddr[2], status, frequency; > > > unsigned int stats[5]; > > > - struct sb1000_private *lp = netdev_priv(dev); > > > + struct sb1000_private *lp; > > > > > > if (!(dev && dev->flags & IFF_UP)) > > > return -ENODEV; > > I think we could get rid of the !dev check itself. Actually, the IFF_UP > check /also/ looks suspect to me for two reasons: (1) I remember Stephen > Hemminger once telling me dev->flags is legacy and unsafe, and one of > the netif_xxx() functions be used instead, and, (2) I wonder if we really > require the interface to be up and *running* when we do this ioctl.
Updated patch below.
[PATCH] sb1000: Remove bogus checks
In net_device->do_ioctl() of the sb1000 driver (sb1000_dev_ioctl):
(1) !dev condition is always false -- this function cannot be called with NULL net_device. (2) !(dev->flags & IFF_UP) is bogus because the functions of this ioctl can (and should) be allowed even when the interface is not up and running.
So let's remove these checks.
Signed-off-by: Satyam Sharma <satyam@infradead.org> Cc: Jesper Juhl <jesper.juhl@gmail.com> Cc: Domen Puncer <domen@coderock.org>
---
drivers/net/sb1000.c | 3 --- 1 files changed, 0 insertions(+), 3 deletions(-)
diff --git a/drivers/net/sb1000.c b/drivers/net/sb1000.c index 1de3eec..f60fe98 100644 --- a/drivers/net/sb1000.c +++ b/drivers/net/sb1000.c @@ -993,9 +993,6 @@ static int sb1000_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) unsigned int stats[5]; struct sb1000_private *lp = netdev_priv(dev); - if (!(dev && dev->flags & IFF_UP)) - return -ENODEV; - ioaddr[0] = dev->base_addr; /* mem_start holds the second I/O address */ ioaddr[1] = dev->mem_start; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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