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 794B3221F18; Mon, 24 Feb 2025 11:20:49 +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=1740396049; cv=none; b=bPX1PfD13bdBGNLf5l+0+mHeToAm/SNRdp5lN/682VHUv0j+li0B55yvsJJqzYXkX+Qkyu1TmJEnkTozljq0h71dFcZ/x6d3cV82jTgt0cbp4dCwSgoehJPhaVC/6rKhKR/gGqEgJGxsDE5FLrwXpg9Vg5NnajtMNeB1wEWUOAA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740396049; c=relaxed/simple; bh=Aw1AhRCRe0h7xFMnZoKTzgHuSv27yUk9wz8rZ4NUg7Y=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=HNuN4sMSVylSyriDDjqsqURE0WXXBr4liDDCa+ewHsiagLsDZ5x+K29bHvw7Y8fjpCCtAooxVUgUNeMFdyF6xdPcxHPqDxJtrfEheRkigV0mCLHpmtQdkAJfgex6C4z439lk1ldmEtl06B6XA0zEFy/8mylK2eb1SzHOSXczkOU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DTXWYUZW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DTXWYUZW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8B1BC4CEE6; Mon, 24 Feb 2025 11:20:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740396049; bh=Aw1AhRCRe0h7xFMnZoKTzgHuSv27yUk9wz8rZ4NUg7Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DTXWYUZWcBPb9ILS2OLpZRuwRsthPm5zEVkX4bmZccwTYTfmDQNwfRSaF0syumMfb HxRpAtX74yrSu4y8SVWsY8b/SpJ5gtJkZZkKrRzYBV0Xyj9GnX9sxyIfMw0MRJvPBB qatsvBramnhEpuEtDtzIOxLZId2q0XYKaLqvx/2dmRUOzICas0hPTGuCXuBROoVtJo rnJhVOpn7o4CIekCuQfpg7IxU+yxBko33/xvfo78awvGTyA2PcOGsLs5SScQthUU+r Gm+nEcyIF/M2M8KyPGGoP1hsc4i7TEEJFCLD8OKx/jV9+eBcEWwcnsdbv7+71UBcE7 2RfAzgW4Ci1Pw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yu-Chun Lin , Jakub Kicinski , Sasha Levin , marcelo.leitner@gmail.com, lucien.xin@gmail.com, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, linux-sctp@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 6/7] sctp: Fix undefined behavior in left shift operation Date: Mon, 24 Feb 2025 06:20:29 -0500 Message-Id: <20250224112033.2214818-6-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250224112033.2214818-1-sashal@kernel.org> References: <20250224112033.2214818-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-sctp@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.15.178 Content-Transfer-Encoding: 8bit From: Yu-Chun Lin [ Upstream commit 606572eb22c1786a3957d24307f5760bb058ca19 ] According to the C11 standard (ISO/IEC 9899:2011, 6.5.7): "If E1 has a signed type and E1 x 2^E2 is not representable in the result type, the behavior is undefined." Shifting 1 << 31 causes signed integer overflow, which leads to undefined behavior. Fix this by explicitly using '1U << 31' to ensure the shift operates on an unsigned type, avoiding undefined behavior. Signed-off-by: Yu-Chun Lin Link: https://patch.msgid.link/20250218081217.3468369-1-eleanor15x@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sctp/stream.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sctp/stream.c b/net/sctp/stream.c index ee6514af830f7..0527728aee986 100644 --- a/net/sctp/stream.c +++ b/net/sctp/stream.c @@ -735,7 +735,7 @@ struct sctp_chunk *sctp_process_strreset_tsnreq( * value SHOULD be the smallest TSN not acknowledged by the * receiver of the request plus 2^31. */ - init_tsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + (1 << 31); + init_tsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + (1U << 31); sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL, init_tsn, GFP_ATOMIC); -- 2.39.5