From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 838791E9906; Thu, 30 Jan 2025 14:21:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738246876; cv=none; b=l+pLfJw0PAntQw/zSArWEq5SDI6sEiovS7vd9YTF6NN4zch0cWRguYfguo/VxH1UBiI4lPMzM1GBjJAco3rI5lhnWKIrlOHSqaq9Pn0AipdjS9hE7MocaSDQbc7ZLX740JdMsseGhdTMIUAmkV+yQn7yErbPfODNM9mLiA1j5H4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738246876; c=relaxed/simple; bh=HLn8CzkK2huCnj6Z5pbv9Pgyaoh/k48rpceUKE2w9lA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IiBXvtUXuE0EbYiYBw/fsIGaAKJePa7xWMYqnjTdooLuwA7nhwS6tOuRhQlyxi+90XhDEaHPmj5bgnMBGYW84Pk1WxLUjO7d6nHinskKwTL7GxA0tDQOXyAuObLp3Y2p1Zc0zB+/TpEMvkwmxJtjYgyLHcqAeKTLNe/L8Ps0GP0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=w8pl1sZC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="w8pl1sZC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0CBCBC4CED2; Thu, 30 Jan 2025 14:21:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738246876; bh=HLn8CzkK2huCnj6Z5pbv9Pgyaoh/k48rpceUKE2w9lA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=w8pl1sZC3YUxxvoBPl5EXO9Bj/G/va18gyxzbZltFLOQfRvMHuatJ2XjCVwfJXnti cE6VxGj+OIoR6kyh0Ai1rXIKCZ+/8KExqey0GGiAzfvHlsdyLxcuzjMQeQRpb1OvKv 7+P0B0vENHctN2+bRLL+O486P9T5dqT8i+H/mKqw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jeongjun Park , Jakub Kicinski , Hagar Hemdan Subject: [PATCH 5.4 83/91] net/xen-netback: prevent UAF in xenvif_flush_hash() Date: Thu, 30 Jan 2025 15:01:42 +0100 Message-ID: <20250130140137.022524835@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250130140133.662535583@linuxfoundation.org> References: <20250130140133.662535583@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeongjun Park commit 0fa5e94a1811d68fbffa0725efe6d4ca62c03d12 upstream. During the list_for_each_entry_rcu iteration call of xenvif_flush_hash, kfree_rcu does not exist inside the rcu read critical section, so if kfree_rcu is called when the rcu grace period ends during the iteration, UAF occurs when accessing head->next after the entry becomes free. Therefore, to solve this, you need to change it to list_for_each_entry_safe. Signed-off-by: Jeongjun Park Link: https://patch.msgid.link/20240822181109.2577354-1-aha310510@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Hagar Hemdan Signed-off-by: Greg Kroah-Hartman --- drivers/net/xen-netback/hash.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/net/xen-netback/hash.c +++ b/drivers/net/xen-netback/hash.c @@ -95,7 +95,7 @@ static u32 xenvif_new_hash(struct xenvif static void xenvif_flush_hash(struct xenvif *vif) { - struct xenvif_hash_cache_entry *entry; + struct xenvif_hash_cache_entry *entry, *n; unsigned long flags; if (xenvif_hash_cache_size == 0) @@ -103,8 +103,7 @@ static void xenvif_flush_hash(struct xen spin_lock_irqsave(&vif->hash.cache.lock, flags); - list_for_each_entry_rcu(entry, &vif->hash.cache.list, link, - lockdep_is_held(&vif->hash.cache.lock)) { + list_for_each_entry_safe(entry, n, &vif->hash.cache.list, link) { list_del_rcu(&entry->link); vif->hash.cache.count--; kfree_rcu(entry, rcu);