Messages in this thread |  | | Date | Mon, 24 Sep 2001 17:26:08 -0700 (PDT) | Subject | Re: [CHECKER] two probable security holes | From | "David S. Miller" <> |
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From: Ken Ashcraft <kash@stanford.edu> Date: Tue, 18 Sep 2001 14:29:57 -0700 (PDT)
Watch ifr.ifr_name.
Hi Ken, I believe there is some bug in your new checker algorithms for this case.
struct ifreq ifr; int err; Start---> if (copy_from_user(&ifr, (void *)arg, sizeof(ifr))) return -EFAULT; ifr.ifr_name[IFNAMSIZ-1] = '\0';
ifreq copied safely to kernel space, ifr.ifr_name[] is inside the struct and NOT a user pointer.
err = tun_set_iff(file, &ifr);
Pass address of kernel ifreq.
if (*ifr->ifr_name) name = ifr->ifr_name; if ((err = dev_alloc_name(&tun->dev, name)) < 0) goto failed;
Perfectly fine still, name always points to kernel memory. int dev_alloc_name(struct net_device *dev, const char *name) { ...
for (i = 0; i < 100; i++) { Error---> sprintf(buf,name,i);
Still fine, as stated "name" is pointing to kernel memory.
Perhaps your code is being confused by "ifreq->if_name" being an array.
Franks a lot, David S. Miller davem@redhat.com - 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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