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 665B1264627; Tue, 8 Apr 2025 12:05:24 +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=1744113924; cv=none; b=co8hrLi6MHf+KXd/L7C0divIb2WWl7TbtP6G2oulkuqcnIZd5OSU1GH+82fo5bvNh1y7HQQ6Ei5DVw31saMzvV5sy+M8XZRNAuFDk+9cMe2uqThGcUust2O3iS1NdLr91b75P5jNcmeHZBC9UBGDzHoXR4gsbdJgqj2OC4XQiCg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744113924; c=relaxed/simple; bh=fWPPogGVH0sNXwG21E07agZCJJkOfVJFPDzUbQI/VbE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fpGHlM43vwIBbcsDtinp/02IMYHyE5oSHuB+KJ/K+bPDnbsEej4bO9vfYWE/SBf/koy8e5w96Vv09qSJT0FWayVSozNmkol5Wzg6qJmgpGxB0icOY1pl2aS63YV0Vdryxr/D/9LhkvQiihw9E9sX2JaoDKvIIc8zSn1ZuRlZz0o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JS7xzQOo; 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="JS7xzQOo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC240C4CEE7; Tue, 8 Apr 2025 12:05:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744113924; bh=fWPPogGVH0sNXwG21E07agZCJJkOfVJFPDzUbQI/VbE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JS7xzQOoqDLqgNlsoaDkSXkZ6hDRoVwXdiHcODIr2cGioX8Ovc+XuvlExEG3IppnQ 4sLYkBTvAYr4J4lEV9rOKVIUndT7F+nXhiW670ZcPiPMCLKqxhsWDj5oxxZ/cgDL/E /6J7wsLO1vVQZVPeaZ26ZMAYrP43+dSi0OH4yARs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yu-Chun Lin , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 032/154] sctp: Fix undefined behavior in left shift operation Date: Tue, 8 Apr 2025 12:49:33 +0200 Message-ID: <20250408104816.288444281@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104815.295196624@linuxfoundation.org> References: <20250408104815.295196624@linuxfoundation.org> User-Agent: quilt/0.68 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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ 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 ca8fdc9abca5f..08cd06078fab1 100644 --- a/net/sctp/stream.c +++ b/net/sctp/stream.c @@ -736,7 +736,7 @@ 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