From: Phillip Potter <phil@philpotter.co.uk>
To: davem@davemloft.net
Cc: kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] net: tun: set tun->dev->addr_len during TUNSETLINK processing
Date: Mon, 5 Apr 2021 12:35:55 +0100 [thread overview]
Message-ID: <20210405113555.9419-1-phil@philpotter.co.uk> (raw)
When changing type with TUNSETLINK ioctl command, set tun->dev->addr_len
to match the appropriate type, using new tun_get_addr_len utility function
which returns appropriate address length for given type. Fixes a
KMSAN-found uninit-value bug reported by syzbot at:
https://syzkaller.appspot.com/bug?id=0766d38c656abeace60621896d705743aeefed51
Reported-by: syzbot+001516d86dbe88862cec@syzkaller.appspotmail.com
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
---
drivers/net/tun.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 978ac0981d16..56c26339ee3b 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -69,6 +69,14 @@
#include <linux/bpf.h>
#include <linux/bpf_trace.h>
#include <linux/mutex.h>
+#include <linux/ieee802154.h>
+#include <linux/if_ltalk.h>
+#include <uapi/linux/if_fddi.h>
+#include <uapi/linux/if_hippi.h>
+#include <uapi/linux/if_fc.h>
+#include <net/ax25.h>
+#include <net/rose.h>
+#include <net/6lowpan.h>
#include <linux/uaccess.h>
#include <linux/proc_fs.h>
@@ -2925,6 +2933,45 @@ static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
return __tun_set_ebpf(tun, prog_p, prog);
}
+/* Return correct value for tun->dev->addr_len based on tun->dev->type. */
+static inline unsigned char tun_get_addr_len(unsigned short type)
+{
+ switch (type) {
+ case ARPHRD_IP6GRE:
+ case ARPHRD_TUNNEL6:
+ return sizeof(struct in6_addr);
+ case ARPHRD_IPGRE:
+ case ARPHRD_TUNNEL:
+ case ARPHRD_SIT:
+ return 4;
+ case ARPHRD_ETHER:
+ return ETH_ALEN;
+ case ARPHRD_IEEE802154:
+ case ARPHRD_IEEE802154_MONITOR:
+ return IEEE802154_EXTENDED_ADDR_LEN;
+ case ARPHRD_PHONET_PIPE:
+ case ARPHRD_PPP:
+ case ARPHRD_NONE:
+ return 0;
+ case ARPHRD_6LOWPAN:
+ return EUI64_ADDR_LEN;
+ case ARPHRD_FDDI:
+ return FDDI_K_ALEN;
+ case ARPHRD_HIPPI:
+ return HIPPI_ALEN;
+ case ARPHRD_IEEE802:
+ return FC_ALEN;
+ case ARPHRD_ROSE:
+ return ROSE_ADDR_LEN;
+ case ARPHRD_NETROM:
+ return AX25_ADDR_LEN;
+ case ARPHRD_LOCALTLK:
+ return LTALK_ALEN;
+ default:
+ return 0;
+ }
+}
+
static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
unsigned long arg, int ifreq_len)
{
@@ -3088,6 +3135,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
break;
}
tun->dev->type = (int) arg;
+ tun->dev->addr_len = tun_get_addr_len(tun->dev->type);
netif_info(tun, drv, tun->dev, "linktype set to %d\n",
tun->dev->type);
call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
--
2.30.2
next reply other threads:[~2021-04-05 11:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-05 11:35 Phillip Potter [this message]
2021-04-05 21:59 ` [PATCH] net: tun: set tun->dev->addr_len during TUNSETLINK processing David Miller
2021-04-06 10:18 ` Phillip Potter
2021-04-06 17:26 ` Eric Dumazet
2021-04-06 17:38 ` Phillip Potter
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