ipv4: snapshot dst.dev in ip_rt_send_redirect() and ip_rt_get_source()

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rt_flush_dev() can replace rt->dst.dev with blackhole_netdev while RCU
readers are running.  ip_rt_send_redirect() and ip_rt_get_source() both
read rt->dst.dev more than once and use the results in one operation.

If rt->dst.dev changes between those reads, the operation can use values
from two devices.  For example, ip_rt_send_redirect() can use in_dev from
the old device and the L3 master ifindex from blackhole_netdev.

Read rt->dst.dev once in these two functions and use the snapshot for the
later device accesses.

Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260708060537.17188-3-xuanqiang.luo@linux.dev
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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Xuanqiang Luo 2026-07-08 14:05:37 +08:00 • committed by Paolo Abeni

parent 1469773b24

commit 7804eaa057

1 changed files with 18 additions and 13 deletions

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net/ipv4/route.c

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