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authorWANG Cong <xiyou.wangcong@gmail.com>2017-07-26 15:22:06 -0700
committerDavid S. Miller <davem@davemloft.net>2017-07-29 11:25:05 -0700
commit0254e0c632bfe4a0cf610e2d90397474144f00d2 (patch)
tree80b3164f82ae010a864fff268ffc5c1fb40119b9 /net/core/dev_ioctl.c
parent245db3c349e0b413e0fec8d6179f6b767649ad63 (diff)
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net: check dev->addr_len for dev_set_mac_address()
Historically, dev_ifsioc() uses struct sockaddr as mac address definition, this is why dev_set_mac_address() accepts a struct sockaddr pointer as input but now we have various types of mac addresse whose lengths are up to MAX_ADDR_LEN, longer than struct sockaddr, and saved in dev->addr_len. It is too late to fix dev_ifsioc() due to API compatibility, so just reject those larger than sizeof(struct sockaddr), otherwise we would read and use some random bytes from kernel stack. Fortunately, only a few IPv6 tunnel devices have addr_len larger than sizeof(struct sockaddr) and they don't support ndo_set_mac_addr(). But with team driver, in lb mode, they can still be enslaved to a team master and make its mac addr length as the same. Cc: Jiri Pirko <jiri@resnulli.us> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev_ioctl.c')
-rw-r--r--net/core/dev_ioctl.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 06b147d7d9e2..709a4e6fb447 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -263,6 +263,8 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
return dev_set_mtu(dev, ifr->ifr_mtu);
case SIOCSIFHWADDR:
+ if (dev->addr_len > sizeof(struct sockaddr))
+ return -EINVAL;
return dev_set_mac_address(dev, &ifr->ifr_hwaddr);
case SIOCSIFHWBROADCAST: