linux-kernel - [PATCH] net: don't forget to free sk

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Date:	Wed,  6 Nov 2013 19:51:46 +0400
From:	Andrey Vagin <avagin@...nvz.org>
To:	netdev@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Andrey Vagin <avagin@...nvz.org>,
	Alexei Starovoitov <ast@...mgrid.com>,
	Eric Dumazet <edumazet@...gle.com>,
	"David S. Miller" <davem@...emloft.net>,
	stable@...r.kernel.org.#.3.12
Subject: [PATCH] net: don't forget to free sk_filter

sk_filter isn't freed if bpf_func is equal to sk_run_filter.

This memory leak was introduced by
commit d45ed4a4e33ae103053c0a53d280014e7101bb5c
Author: Alexei Starovoitov <ast@...mgrid.com>
Date:   Fri Oct 4 00:14:06 2013 -0700

    net: fix unsafe set_memory_rw from softirq

Before this patch sk_filter was freed in sk_filter_release_rcu,
now it is freed in bpf_jit_free.

Here is output of kmemleak:
unreferenced object 0xffff8800b774eab0 (size 128):
  comm "systemd", pid 1, jiffies 4294669014 (age 124.062s)
  hex dump (first 32 bytes):
    00 00 00 00 0b 00 00 00 20 63 7f b7 00 88 ff ff  ........ c......
    60 d4 55 81 ff ff ff ff 30 d9 55 81 ff ff ff ff  `.U.....0.U.....
  backtrace:
    [<ffffffff816444be>] kmemleak_alloc+0x4e/0xb0
    [<ffffffff811845af>] __kmalloc+0xef/0x260
    [<ffffffff81534028>] sock_kmalloc+0x38/0x60
    [<ffffffff8155d4dd>] sk_attach_filter+0x5d/0x190
    [<ffffffff815378a1>] sock_setsockopt+0x991/0x9e0
    [<ffffffff81531bd6>] SyS_setsockopt+0xb6/0xd0
    [<ffffffff8165f3e9>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff

Cc: Alexei Starovoitov <ast@...mgrid.com>
Cc: Eric Dumazet <edumazet@...gle.com>
Cc: "David S. Miller" <davem@...emloft.net>
Cc: stable@...r.kernel.org # 3.12
Signed-off-by: Andrey Vagin <avagin@...nvz.org>
---
 arch/x86/net/bpf_jit_comp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 516593e..3c55de5 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -788,5 +788,6 @@ void bpf_jit_free(struct sk_filter *fp)
 	if (fp->bpf_func != sk_run_filter) {
 		INIT_WORK(&fp->work, bpf_jit_free_deferred);
 		schedule_work(&fp->work);
-	}
+	} else
+		kfree(fp);
 }
-- 
1.8.3.1

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