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 6323C35F15 for ; Wed, 15 Nov 2023 22:02:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="veG33ag0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06387C433C8; Wed, 15 Nov 2023 22:02:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700085733; bh=4iHDDRjvHrKTOU2pu7ICCRA1+ox8MImQGdpb3CL2WkI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=veG33ag0Qh1tbCaIzU6SCw9qMtavD7Y040YZF8nGmljvF8eo5G8yVZuAZFOaZ5Vw6 oxf7w/WKnZgxOphFNnF8ukPGIU0CyTGz/8bHjER+Q/lSKapgwTy1hqlA70jpv0eO9S jLjq1Cs1YISIJujn8SqutA9hpzyc6tiCL7A933qA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 018/119] tcp: fix cookie_init_timestamp() overflows Date: Wed, 15 Nov 2023 17:00:08 -0500 Message-ID: <20231115220133.176840983@linuxfoundation.org> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231115220132.607437515@linuxfoundation.org> References: <20231115220132.607437515@linuxfoundation.org> User-Agent: quilt/0.67 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: Eric Dumazet [ Upstream commit 73ed8e03388d16c12fc577e5c700b58a29045a15 ] cookie_init_timestamp() is supposed to return a 64bit timestamp suitable for both TSval determination and setting of skb->tstamp. Unfortunately it uses 32bit fields and overflows after 2^32 * 10^6 nsec (~49 days) of uptime. Generated TSval are still correct, but skb->tstamp might be set far away in the past, potentially confusing other layers. tcp_ns_to_ts() is changed to return a full 64bit value, ts and ts_now variables are changed to u64 type, and TSMASK is removed in favor of shifts operations. While we are at it, change this sequence: ts >>= TSBITS; ts--; ts <<= TSBITS; ts |= options; to: ts -= (1UL << TSBITS); Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/tcp.h | 2 +- net/ipv4/syncookies.c | 20 +++++++------------- 2 files changed, 8 insertions(+), 14 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 2be7d26434180..af67e19eba392 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -776,7 +776,7 @@ static inline u32 tcp_time_stamp(const struct tcp_sock *tp) } /* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */ -static inline u32 tcp_ns_to_ts(u64 ns) +static inline u64 tcp_ns_to_ts(u64 ns) { return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ); } diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 88d53d37fbe96..3cc22f776a313 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -43,7 +43,6 @@ static siphash_key_t syncookie_secret[2] __read_mostly; * requested/supported by the syn/synack exchange. */ #define TSBITS 6 -#define TSMASK (((__u32)1 << TSBITS) - 1) static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport, u32 count, int c) @@ -64,27 +63,22 @@ static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport, */ u64 cookie_init_timestamp(struct request_sock *req, u64 now) { - struct inet_request_sock *ireq; - u32 ts, ts_now = tcp_ns_to_ts(now); + const struct inet_request_sock *ireq = inet_rsk(req); + u64 ts, ts_now = tcp_ns_to_ts(now); u32 options = 0; - ireq = inet_rsk(req); - options = ireq->wscale_ok ? ireq->snd_wscale : TS_OPT_WSCALE_MASK; if (ireq->sack_ok) options |= TS_OPT_SACK; if (ireq->ecn_ok) options |= TS_OPT_ECN; - ts = ts_now & ~TSMASK; + ts = (ts_now >> TSBITS) << TSBITS; ts |= options; - if (ts > ts_now) { - ts >>= TSBITS; - ts--; - ts <<= TSBITS; - ts |= options; - } - return (u64)ts * (NSEC_PER_SEC / TCP_TS_HZ); + if (ts > ts_now) + ts -= (1UL << TSBITS); + + return ts * (NSEC_PER_SEC / TCP_TS_HZ); } -- 2.42.0