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| author | Francesco Ruggeri <fruggeri@aristanetworks.com> | 2016-01-06 00:18:48 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-01-28 21:57:11 -0800 |
| commit | 003b127e3c9e5bc83249e1106fd3de9da8dcf741 (patch) | |
| tree | 12d2801dcb9a6135dd84fe761fd13ca450ccf2ec /net | |
| parent | edb36218850126923fd07b0637ab669163de57d4 (diff) | |
| download | lwn-003b127e3c9e5bc83249e1106fd3de9da8dcf741.tar.gz lwn-003b127e3c9e5bc83249e1106fd3de9da8dcf741.zip | |
net: possible use after free in dst_release
[ Upstream commit 07a5d38453599052aff0877b16bb9c1585f08609 ]
dst_release should not access dst->flags after decrementing
__refcnt to 0. The dst_entry may be in dst_busy_list and
dst_gc_task may dst_destroy it before dst_release gets a chance
to access dst->flags.
Fixes: d69bbf88c8d0 ("net: fix a race in dst_release()")
Fixes: 27b75c95f10d ("net: avoid RCU for NOCACHE dst")
Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dst.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/dst.c b/net/core/dst.c index c07070544e3f..74d1ad1285d0 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -280,10 +280,11 @@ void dst_release(struct dst_entry *dst) { if (dst) { int newrefcnt; + unsigned short nocache = dst->flags & DST_NOCACHE; newrefcnt = atomic_dec_return(&dst->__refcnt); WARN_ON(newrefcnt < 0); - if (!newrefcnt && unlikely(dst->flags & DST_NOCACHE)) + if (!newrefcnt && unlikely(nocache)) call_rcu(&dst->rcu_head, dst_destroy_rcu); } } |