net: arp: terminate device name before lookup

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The ARP ioctl copies a user-provided struct arpreq into a stack object. Its
arp_dev field may contain IFNAMSIZ bytes without a NUL terminator.

Such input is passed to dev_get_by_name_rcu() or __dev_get_by_name(), where
strcmp() can read past the end of the stack object when a matching
alternative interface name exists.

Terminate the field before the lookup to prevent the out-of-bounds read.

Fixes: 36fbf1e52b ("net: rtnetlink: add linkprop commands to add and delete alternative ifnames")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Zijie Huang <milkory@outlook.com>
Signed-off-by: Ren Wei <weir@nebusec.ai>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/fabf02a70787d17299e4b3153eadffaf20d154b3.1789910973.git.milkory@outlook.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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Zijie Huang 2026-09-21 01:36:19 +08:00 • committed by Jakub Kicinski

parent 89a8a1eef2

commit d8b6529e80

1 changed files with 1 additions and 0 deletions

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net/ipv4/arp.c

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