netlink: Always copy on mmap TX.

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commit 4682a03586 upstream.

Checking the file f_count and the nlk->mapped count is not completely
sufficient to prevent the mmap'd area contents from changing from
under us during netlink mmap sendmsg() operations.

Be careful to sample the header's length field only once, because this
could change from under us as well.

Fixes: 5fd96123ee ("netlink: implement memory mapped sendmsg()")
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

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David Miller 2014-12-16 17:58:17 -05:00 • committed by Luis Henriques

parent 9fc3d4163f

commit d373e19bf8

1 changed files with 16 additions and 36 deletions

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net/netlink/af_netlink.c

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