From patchwork Tue Jan 23 00:26:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 13526636 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-pf1-f172.google.com (mail-pf1-f172.google.com [209.85.210.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A09FF155A55 for ; Tue, 23 Jan 2024 00:28:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705969725; cv=none; b=GhI3zQR9ZH24va01G/bQ8Vlsnvw7dD3Y3L6TBlZVCXilHnTEvqWFTywFfixeYJBYfm5OH70ULXyeq/I4LZK2mMnqN3A63y4js7rxsL9CnGh9XNoFOh3jCVDLbSIU4fJhD93JpXgz7YjVGj9xwhuMU+QzIXnOxAEwOGK5EYaYmX0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705969725; c=relaxed/simple; bh=gNYUL4lkD/q4q2Iw6mvmjCERgWt/Zx4ayDxuFa3qc3A=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=GfiLZLJvFApqq0qgA1COpY5l5kzlu//ORwF5WK9/WnTNiz7cTDAa8S91Lfab3ctuNEWCn8bUD1zQLVgZpIeCBNAHBTadzSzaR5CtAP98PodsXZFR9EWqi0DfMpSnc33CmMk7u/DnVrySA82U+oFmGfHLPKpaPlaG8296qLNhZWQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=aRs2Fpzh; arc=none smtp.client-ip=209.85.210.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="aRs2Fpzh" Received: by mail-pf1-f172.google.com with SMTP id d2e1a72fcca58-6db9e52bbccso2116002b3a.3 for ; Mon, 22 Jan 2024 16:28:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1705969723; x=1706574523; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=WnvzwX4y80p5z83E6IpBrKurnrIIBIFVjaFxfKXwLnU=; b=aRs2FpzhVlwpX6B1WZcqtvJnPve6adqUUdPqokmDearzfsvYssSEJIYvCbYUSAeN37 0Tu6lm0QwtCkMjZvyE6guBPdsh8NHE9CPt1sayLebWOAFOrX5KpPGVZYXmde/2IvP47Y 6ozI5NtgJjfNtiyyig6NJyZ6KPvfCAyMidGhg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705969723; x=1706574523; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=WnvzwX4y80p5z83E6IpBrKurnrIIBIFVjaFxfKXwLnU=; b=iD62653HWH1asjJY6uvSTEgH5FFO5Nh/TgR3GDpUP+2GckHIgLxlSdt5GwQbm/1z7c +8fgbH2S4JqhLIIzb4pAABI0AYUzNrS2tLT5043I7nC1httzv+iUsSVGumfQ5B8I6suG fBEd1GFWSEvmuMulxHsf2OnHQgp5MKnlkpqrCQkRwDrWsl2MdC4D8JN4/+tTNffCFxDW jqxI+YFp7ELpcmxNbHiAnfnWkrGM8L7/ArUHE7/EBjLTiTAQksDn/HtMOy5lXJdCI4WM i1b8UvMpulMymM8qOp1SZICRe2LD7BzX4o9kl1O9CcGXVRSt26bUZqfTCNuJaMnELb00 Mcfg== X-Gm-Message-State: AOJu0Yyfh0SzXQeMl4/+9Gf7gYelDu+6VDnkibt1y/XWcB7VDuQditMp 4bgIQNMevXqJMaEV2TVsK/PCR/Sd6qiaAvsPdtDmzmdCYWKsfU7H+SBGrJIqWg== X-Google-Smtp-Source: AGHT+IHqWbCdbj4COoKXEiHtTaOvD5DiZiG+2we1Qlvg+cDhbkuK7H6vgq1QJRL6IheoOiqRzXhQFA== X-Received: by 2002:a05:6a00:2e9e:b0:6db:d040:4d05 with SMTP id fd30-20020a056a002e9e00b006dbd0404d05mr2702259pfb.22.1705969722109; Mon, 22 Jan 2024 16:28:42 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id j18-20020a056a00175200b006dbd8dd4d49sm3283190pfc.112.2024.01.22.16.28.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:28:37 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , Jakub Kicinski , "David S. Miller" , David Ahern , Eric Dumazet , Paolo Abeni , netdev@vger.kernel.org, "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: [PATCH 12/82] ipv4: Silence intentional wrapping addition Date: Mon, 22 Jan 2024 16:26:47 -0800 Message-Id: <20240123002814.1396804-12-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240122235208.work.748-kees@kernel.org> References: <20240122235208.work.748-kees@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2170; i=keescook@chromium.org; h=from:subject; bh=gNYUL4lkD/q4q2Iw6mvmjCERgWt/Zx4ayDxuFa3qc3A=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgFvlBO2la5fghnKIu98p+FkONV/wNVLTQSX IKk33CsfLWJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8IBQAKCRCJcvTf3G3A JrmBD/9kKc8XzjSQWEXd+h2tu5y1xWCQNfVqCF8dPAmWo/5I58GZuuA5f0M1dCs8yLp/C8K+gn2 VK1GNKHkGaTKkIuLqGdzPCV6K0KdIFC1RD9GWJCaPAKIH1ECgMvXF1pdJPgU3nVMvA5aEWn7S+l Yjz26ICJMWCYFnODX3nnptzdaOXv/giXZfGfPsfy8GpjWspiOnSLvKAzppic92dnlscOIYhAdzB qqh+Mxo7z04JwgzJT1sPoc/t0TRsmfabuJshG6qjUM6EfsCHUR/hBZP1TByMomhhjKZ6P8/pTxI bNZF2LT8ST8/uyEx4XzId+YeMdS66RVCa5tVAuWRQBXXzqAaDWExi+yjj1jbgBReLolsbbuOSc4 yV+wC/7eXE0+vH6mVN2Vnae+iO0BS/UN7WUy3GJ7VJK/p+fNcuwOXVW22rI0hu5++1l09g1KUdJ WNNuP6lgZITL1NcGzIePLIoHjlXg2Ojobu//ovxGxWtoOoYX95DwVrnDQpO2sC0OVjAIuDgdOY4 GOflLXPfmQWqRL53HgQNsFra7YLRm7D8mncQQRH+32SCoDsTrX+MFpKEkWwLraLheDi+0D+NjvT BV5/C9ql6p4WXJsvsGJB9Cu8v2eZ2Z/mv0OAWOuD0cNL8umP0Ps9I8ak+NZ7xOs+drWeBXjzu1k 0xgg6au/qio0hFg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 X-Patchwork-Delegate: kuba@kernel.org The overflow sanitizer quickly noticed what appears to have been an old sore spot involving intended wrap around: [ 22.192362] ------------[ cut here ]------------ [ 22.193329] UBSAN: signed-integer-overflow in ../arch/x86/include/asm/atomic.h:85:11 [ 22.194844] 1469769800 + 1671667352 cannot be represented in type 'int' [ 22.195975] CPU: 2 PID: 2260 Comm: nmbd Not tainted 6.7.0 #1 [ 22.196927] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 [ 22.198231] Call Trace: [ 22.198641] [ 22.198641] dump_stack_lvl+0x64/0x80 [ 22.199533] handle_overflow+0x152/0x1a0 [ 22.200382] __ip_select_ident+0xe3/0x100 Explicitly perform a wrapping addition to solve for the needed -fno-strict-overflow behavior but still allow the sanitizers to operate correctly. To see the (unchanged) assembly results more clearly, see: https://godbolt.org/z/EhYhz6zTT Cc: Jakub Kicinski Cc: "David S. Miller" Cc: David Ahern Cc: Eric Dumazet Cc: Paolo Abeni Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook --- net/ipv4/route.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 16615d107cf0..c52e85b06fe7 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -473,11 +473,11 @@ static u32 ip_idents_reserve(u32 hash, int segs) if (old != now && cmpxchg(p_tstamp, old, now) == old) delta = get_random_u32_below(now - old); - /* If UBSAN reports an error there, please make sure your compiler - * supports -fno-strict-overflow before reporting it that was a bug - * in UBSAN, and it has been fixed in GCC-8. + /* If UBSAN reports an error there, please make sure your arch's + * atomic_add_return() implementation has been annotated with + * __signed_wrap. */ - return atomic_add_return(segs + delta, p_id) - segs; + return atomic_add_return(add_wrap(segs, delta), p_id) - segs; } void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)