netdev - [PATCH 08/11] xfrm: don't call xfrm_policy_cache

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 11 Jan 2018 12:37:43 +0100
From:   Steffen Klassert <steffen.klassert@...unet.com>
To:     David Miller <davem@...emloft.net>
CC:     Herbert Xu <herbert@...dor.apana.org.au>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        <netdev@...r.kernel.org>
Subject: [PATCH 08/11] xfrm: don't call xfrm_policy_cache_flush while holding spinlock

From: Florian Westphal <fw@...len.de>

xfrm_policy_cache_flush can sleep, so it cannot be called while holding
a spinlock.  We could release the lock first, but I don't see why we need
to invoke this function here in first place, the packet path won't reuse
an xdst entry unless its still valid.

While at it, add an annotation to xfrm_policy_cache_flush, it would
have probably caught this bug sooner.

Fixes: ec30d78c14a813 ("xfrm: add xdst pcpu cache")
Reported-by: syzbot+e149f7d1328c26f9c12f@...kaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 net/xfrm/xfrm_policy.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 2ef6db98e9ba..bc5eae12fb09 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -975,8 +975,6 @@ int xfrm_policy_flush(struct net *net, u8 type, bool task_valid)
 	}
 	if (!cnt)
 		err = -ESRCH;
-	else
-		xfrm_policy_cache_flush();
 out:
 	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);
 	return err;
@@ -1744,6 +1742,8 @@ void xfrm_policy_cache_flush(void)
 	bool found = 0;
 	int cpu;
 
+	might_sleep();
+
 	local_bh_disable();
 	rcu_read_lock();
 	for_each_possible_cpu(cpu) {
-- 
2.14.1