diff options
author | Cong Wang <cong.wang@bytedance.com> | 2021-02-11 11:34:10 -0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-07 12:20:43 +0100 |
commit | 176188cff67ec1aa55103647b61d02315cc38e98 (patch) | |
tree | 0f4d4eb86b24fda8824d07efef85887ed059558a /Documentation | |
parent | e4fc812e3577f3673c59a8983f901761fdae6726 (diff) |
net: fix dev_ifsioc_locked() race condition
commit 3b23a32a63219f51a5298bc55a65ecee866e79d0 upstream.
dev_ifsioc_locked() is called with only RCU read lock, so when
there is a parallel writer changing the mac address, it could
get a partially updated mac address, as shown below:
Thread 1 Thread 2
// eth_commit_mac_addr_change()
memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
// dev_ifsioc_locked()
memcpy(ifr->ifr_hwaddr.sa_data,
dev->dev_addr,...);
Close this race condition by guarding them with a RW semaphore,
like netdev_get_name(). We can not use seqlock here as it does not
allow blocking. The writers already take RTNL anyway, so this does
not affect the slow path. To avoid bothering existing
dev_set_mac_address() callers in drivers, introduce a new wrapper
just for user-facing callers on ioctl and rtnetlink paths.
Note, bonding also changes slave mac addresses but that requires
a separate patch due to the complexity of bonding code.
Fixes: 3710becf8a58 ("net: RCU locking for simple ioctl()")
Reported-by: "Gong, Sishuai" <sishuai@purdue.edu>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions