Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 37/53] net: possible use after free in dst_release | Date | Wed, 27 Jan 2016 10:15:56 -0800 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Francesco Ruggeri <fruggeri@aristanetworks.com>
[ 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> --- net/core/dst.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- 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); } }
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