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| author | Francesco Ruggeri <fruggeri@aristanetworks.com> | 2016-01-06 00:18:48 -0800 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2016-10-26 23:15:42 +0800 |
| commit | edd32246ed08de91f2270e7c4b0b65bbec6aba09 (patch) | |
| tree | 7109da519ba700f8d7facf9cfeda4f8e1f3fd965 | |
| parent | 626c6e6e6f4bd8b212d3cd1d552896751346c085 (diff) | |
| download | linux-stable-edd32246ed08de91f2270e7c4b0b65bbec6aba09.tar.gz linux-stable-edd32246ed08de91f2270e7c4b0b65bbec6aba09.tar.bz2 linux-stable-edd32246ed08de91f2270e7c4b0b65bbec6aba09.zip | |
net: possible use after free in dst_release
commit 07a5d38453599052aff0877b16bb9c1585f08609 upstream.
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>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
| -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 54ba1ebba30e..48cff898b5a4 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -269,10 +269,11 @@ 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)) { dst = dst_destroy(dst); if (dst) __dst_free(dst); |