udp: fix jump label misuse

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The commit 60fb9567bf ("udp: implement complete book-keeping for
encap_needed") introduced a severe misuse of jump label APIs, which
syzbot, as reported by Eric, was able to exploit.

When multiple sockets/process can concurrently request (and than
disable) the udp encap, we need to track the activation counter with
*_inc()/*_dec() jump label variants, or we can experience bad things
at disable time.

Fixes: 60fb9567bf ("udp: implement complete book-keeping for encap_needed")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Paolo Abeni 2018-11-15 02:34:50 +01:00 • committed by David S. Miller

parent 37342bdaf5

commit 9c48060141

2 changed files with 4 additions and 4 deletions

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4

net/ipv4/udp.c

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4

net/ipv6/udp.c

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