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 A0B97610B; Mon, 14 Oct 2024 14:31:31 +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=1728916291; cv=none; b=an/qNpOG1qsD6tryty3Xkd+GxWxTjbMMSCKUEnA7WX8bgPqAHbMIGaMnPQjMnj8yjYL7HACF5ZWvh8ZNo+JfEtnwkf2TpxLZv+oZ01/xTsrPVY/p7+RRslVuegZn2ge0Fpc+r/cCsqKY9tHkgfJ84dUneXIzofPVPL7vKiGPBak= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728916291; c=relaxed/simple; bh=KBtX9w71HgtmwW/+/1ECRtbz9lq5VdDXs9oCmpt229g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Jm8N0fL+F7TNLRNGnqAepfUJKdo7NM8G3Ct6M5u+Z6ZWTfpuPHGv05c3fl5JLwxdvnYV8oLClP4yhF1rBH52iswW5Ntmz+afSy88iKTwzJZm04DqXG9T+scgFzSn/k5p/LG0Wg8YvEOlWr2fLAwwQED4iRWt75z3BYazKLoUCYk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VRNq6Dey; 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="VRNq6Dey" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 257F7C4CEC3; Mon, 14 Oct 2024 14:31:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728916291; bh=KBtX9w71HgtmwW/+/1ECRtbz9lq5VdDXs9oCmpt229g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VRNq6Dey4NJDeAd877iLDsw4tIREh2SeafjjKQ45QDEeCXg2QYpQLdPMFrIG5aW90 dly+TZ9ecKdU9AfFSw/iZjQTFqagn3CFcZJB4voNsOGtbFQZBdhPhPtN33Ntvl5qR7 53cWM9iAN0b9ZbOI3p4mm6jiuiTI7vdMXvZX4JIc= 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 , Sasha Levin Subject: [PATCH 6.11 140/214] net: do not delay dst_entries_add() in dst_release() Date: Mon, 14 Oct 2024 16:20:03 +0200 Message-ID: <20241014141050.453340247@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241014141044.974962104@linuxfoundation.org> References: <20241014141044.974962104@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 6.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit ac888d58869bb99753e7652be19a151df9ecb35d ] 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 Signed-off-by: Sasha Levin --- net/core/dst.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/net/core/dst.c b/net/core/dst.c index 95f533844f17f..9552a90d4772d 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -109,9 +109,6 @@ static void dst_destroy(struct dst_entry *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); @@ -159,17 +156,27 @@ 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 && rcuref_put(&dst->__rcuref)) + if (dst && rcuref_put(&dst->__rcuref)) { + dst_count_dec(dst); call_rcu_hurry(&dst->rcu_head, dst_destroy_rcu); + } } EXPORT_SYMBOL(dst_release); void dst_release_immediate(struct dst_entry *dst) { - if (dst && rcuref_put(&dst->__rcuref)) + if (dst && rcuref_put(&dst->__rcuref)) { + dst_count_dec(dst); dst_destroy(dst); + } } EXPORT_SYMBOL(dst_release_immediate); -- 2.43.0