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 2888519E992; Tue, 12 Nov 2024 10:32:03 +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=1731407524; cv=none; b=Ddl+2vtpupe0V3e0vf/1xXBBzZOaAotYnMW5B62OAf93m1WyA1hmDuI4MH/m+EAe5UXzJ6g6j8RAMo1uB/yZl6jmNMfvvG4bkAGCTEvDSrp9bGpMe2l2LrE1A3Mc8CXujsVRPHvOnejJ39/1WHWErXKGej0Y9Xp6fES78ZVTr7w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731407524; c=relaxed/simple; bh=thTQ3sPUSA+9QR6vxYA1SNzCiWMGogBLTnnooD9vU14=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Cxy0p5G1Dhd6A6EBr+YK0CjrUvJC73QxQ0SD1E8FqldBqk8bCPrS8bfZrqFPnDVJGKjiWPS6g3ilhtMCSCFqm2toDY56/FKjK2xSKqvMGAYdw3jJHz+rWMtqhjHI8/4FZPmR4cHQZtnC3O2oPrZs1iBOMO0V2730lm0yjlSWJKQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=StHi1IMr; 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="StHi1IMr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEAFCC4CECD; Tue, 12 Nov 2024 10:32:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1731407523; bh=thTQ3sPUSA+9QR6vxYA1SNzCiWMGogBLTnnooD9vU14=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=StHi1IMrk4J6aZUQd+UchDnHKx5J1F232Zur0JvUcQcQGUNbD3qkU3hx4vGSJG+Fe nndFfBBE5PweyprvF4HjkSTz1w9d/L61RygfTnT5fKtEpzycmG3xU0sZQ2VTbyfx4F lL0PKC1h/FzLF03ZsaKl8Op/c2EvB5warTNOR6ic= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Naresh Kamboju , Linux Kernel Functional Testing , Eric Dumazet , Xin Long , Steffen Klassert , Paolo Abeni , Abdelkareem Abdelsaamad Subject: [PATCH 6.1 78/98] net: do not delay dst_entries_add() in dst_release() Date: Tue, 12 Nov 2024 11:21:33 +0100 Message-ID: <20241112101847.225273849@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241112101844.263449965@linuxfoundation.org> References: <20241112101844.263449965@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit ac888d58869bb99753e7652be19a151df9ecb35d upstream. dst_entries_add() uses per-cpu data that might be freed at netns dismantle from ip6_route_net_exit() calling dst_entries_destroy() Before ip6_route_net_exit() can be called, we release all the dsts associated with this netns, via calls to dst_release(), which waits an rcu grace period before calling dst_destroy() dst_entries_add() use in dst_destroy() is racy, because dst_entries_destroy() could have been called already. Decrementing the number of dsts must happen sooner. Notes: 1) in CONFIG_XFRM case, dst_destroy() can call dst_release_immediate(child), this might also cause UAF if the child does not have DST_NOCOUNT set. IPSEC maintainers might take a look and see how to address this. 2) There is also discussion about removing this count of dst, which might happen in future kernels. Fixes: f88649721268 ("ipv4: fix dst race in sk_dst_get()") Closes: https://lore.kernel.org/lkml/CANn89iLCCGsP7SFn9HKpvnKu96Td4KD08xf7aGtiYgZnkjaL=w@mail.gmail.com/T/ Reported-by: Naresh Kamboju Tested-by: Linux Kernel Functional Testing Tested-by: Naresh Kamboju Signed-off-by: Eric Dumazet Cc: Xin Long Cc: Steffen Klassert Reviewed-by: Xin Long Link: https://patch.msgid.link/20241008143110.1064899-1-edumazet@google.com Signed-off-by: Paolo Abeni [ resolved conflict due to bc9d3a9f2afc ("net: dst: Switch to rcuref_t reference counting") is not in the tree ] Signed-off-by: Abdelkareem Abdelsaamad Signed-off-by: Greg Kroah-Hartman --- net/core/dst.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) --- a/net/core/dst.c +++ b/net/core/dst.c @@ -108,9 +108,6 @@ struct dst_entry *dst_destroy(struct dst child = xdst->child; } #endif - if (!(dst->flags & DST_NOCOUNT)) - dst_entries_add(dst->ops, -1); - if (dst->ops->destroy) dst->ops->destroy(dst); netdev_put(dst->dev, &dst->dev_tracker); @@ -160,6 +157,12 @@ void dst_dev_put(struct dst_entry *dst) } EXPORT_SYMBOL(dst_dev_put); +static void dst_count_dec(struct dst_entry *dst) +{ + if (!(dst->flags & DST_NOCOUNT)) + dst_entries_add(dst->ops, -1); +} + void dst_release(struct dst_entry *dst) { if (dst) { @@ -169,8 +172,10 @@ void dst_release(struct dst_entry *dst) if (WARN_ONCE(newrefcnt < 0, "dst_release underflow")) net_warn_ratelimited("%s: dst:%p refcnt:%d\n", __func__, dst, newrefcnt); - if (!newrefcnt) + if (!newrefcnt){ + dst_count_dec(dst); call_rcu(&dst->rcu_head, dst_destroy_rcu); + } } } EXPORT_SYMBOL(dst_release); @@ -184,8 +189,10 @@ void dst_release_immediate(struct dst_en if (WARN_ONCE(newrefcnt < 0, "dst_release_immediate underflow")) net_warn_ratelimited("%s: dst:%p refcnt:%d\n", __func__, dst, newrefcnt); - if (!newrefcnt) + if (!newrefcnt){ + dst_count_dec(dst); dst_destroy(dst); + } } } EXPORT_SYMBOL(dst_release_immediate);