Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1319449 > unrolled thread

[PATCH 4.1 072/127] net: possible use after free in dst_release

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH 4.1 072/127] net: possible use after free in dst_release Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 20:20 +0100

#1319449 — [PATCH 4.1 072/127] net: possible use after free in dst_release

4.1-stable review patch.  If anyone has any objections, please let me know.

------------------

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
@@ -282,10 +282,11 @@ 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);
 	}
 }

[toc] | [standalone]

Back to top | Article view | linux.kernel

csiph-web