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authorPaolo Abeni <pabeni@redhat.com>2018-11-15 02:34:50 +0100
committerDavid S. Miller <davem@davemloft.net>2018-11-16 23:01:56 -0800
commit9c48060141bd937497774546e4bb89b8992be383 (patch)
treeb62996434ab3d9776fe3b5197c38ca6939452434 /net/ipv4
parentetf: Drop all expired packets (diff)
downloadlinux-dev-9c48060141bd937497774546e4bb89b8992be383.tar.xz
linux-dev-9c48060141bd937497774546e4bb89b8992be383.zip
udp: fix jump label misuse
The commit 60fb9567bf30 ("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: 60fb9567bf30 ("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>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/udp.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 6f8890c5bc7e..aff2a8e99e01 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -587,7 +587,7 @@ static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key);
void udp_encap_enable(void)
{
- static_branch_enable(&udp_encap_needed_key);
+ static_branch_inc(&udp_encap_needed_key);
}
EXPORT_SYMBOL(udp_encap_enable);
@@ -2524,7 +2524,7 @@ void udp_destroy_sock(struct sock *sk)
encap_destroy(sk);
}
if (up->encap_enabled)
- static_branch_disable(&udp_encap_needed_key);
+ static_branch_dec(&udp_encap_needed_key);
}
}