From patchwork Fri Mar 25 15:04:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 554314 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 600C7C433EF for ; Fri, 25 Mar 2022 15:07:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359611AbiCYPI5 (ORCPT ); Fri, 25 Mar 2022 11:08:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1359575AbiCYPIw (ORCPT ); Fri, 25 Mar 2022 11:08:52 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4E5A1D9EAC; Fri, 25 Mar 2022 08:07:05 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D6FAD61C1E; Fri, 25 Mar 2022 15:07:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E18DBC340F1; Fri, 25 Mar 2022 15:07:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1648220824; bh=EWu8tlVUvY2P/Q7rfy1gpf/qZdKlhBmhU443XVaCSWw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q3fQx/2lBwxk6z34xmFJWW3Q5k5CIgN2jAZw1KuZovm22ekDx2W5yQlIgzKFQi+mu eHrYTaOdEfZo6XgrJ0MS72I7/130OOpVyS1/ENS5peUpLEcAFJuzJTfPOIkCnScr5j bwMMa1HqVuE6VkvtChvLn1epYY7zZrhzPO9PLJ6s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, valis , Steffen Klassert , Vaibhav Rustagi Subject: [PATCH 4.19 03/20] esp: Fix possible buffer overflow in ESP transformation Date: Fri, 25 Mar 2022 16:04:41 +0100 Message-Id: <20220325150417.110405983@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220325150417.010265747@linuxfoundation.org> References: <20220325150417.010265747@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Steffen Klassert commit ebe48d368e97d007bfeb76fcb065d6cfc4c96645 upstream. The maximum message size that can be send is bigger than the maximum site that skb_page_frag_refill can allocate. So it is possible to write beyond the allocated buffer. Fix this by doing a fallback to COW in that case. v2: Avoid get get_order() costs as suggested by Linus Torvalds. Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible") Reported-by: valis Signed-off-by: Steffen Klassert Signed-off-by: Vaibhav Rustagi Signed-off-by: Greg Kroah-Hartman --- include/net/esp.h | 2 ++ include/net/sock.h | 3 +++ net/core/sock.c | 3 --- net/ipv4/esp4.c | 5 +++++ net/ipv6/esp6.c | 5 +++++ 5 files changed, 15 insertions(+), 3 deletions(-) --- a/include/net/esp.h +++ b/include/net/esp.h @@ -4,6 +4,8 @@ #include +#define ESP_SKB_FRAG_MAXSIZE (PAGE_SIZE << SKB_FRAG_PAGE_ORDER) + struct ip_esp_hdr; static inline struct ip_esp_hdr *ip_esp_hdr(const struct sk_buff *skb) --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2518,6 +2518,9 @@ extern int sysctl_optmem_max; extern __u32 sysctl_wmem_default; extern __u32 sysctl_rmem_default; +/* On 32bit arches, an skb frag is limited to 2^15 */ +#define SKB_FRAG_PAGE_ORDER get_order(32768) + static inline int sk_get_wmem0(const struct sock *sk, const struct proto *proto) { /* Does this proto have per netns sysctl_wmem ? */ --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2207,9 +2207,6 @@ static void sk_leave_memory_pressure(str } } -/* On 32bit arches, an skb frag is limited to 2^15 */ -#define SKB_FRAG_PAGE_ORDER get_order(32768) - /** * skb_page_frag_refill - check that a page_frag contains enough room * @sz: minimum size of the fragment we want to get --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -275,6 +275,7 @@ int esp_output_head(struct xfrm_state *x struct page *page; struct sk_buff *trailer; int tailen = esp->tailen; + unsigned int allocsz; /* this is non-NULL only with UDP Encapsulation */ if (x->encap) { @@ -284,6 +285,10 @@ int esp_output_head(struct xfrm_state *x return err; } + allocsz = ALIGN(skb->data_len + tailen, L1_CACHE_BYTES); + if (allocsz > ESP_SKB_FRAG_MAXSIZE) + goto cow; + if (!skb_cloned(skb)) { if (tailen <= skb_tailroom(skb)) { nfrags = 1; --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -241,6 +241,11 @@ int esp6_output_head(struct xfrm_state * struct page *page; struct sk_buff *trailer; int tailen = esp->tailen; + unsigned int allocsz; + + allocsz = ALIGN(skb->data_len + tailen, L1_CACHE_BYTES); + if (allocsz > ESP_SKB_FRAG_MAXSIZE) + goto cow; if (!skb_cloned(skb)) { if (tailen <= skb_tailroom(skb)) {