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 CD7291C5F2D; Wed, 19 Mar 2025 14:35:20 +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=1742394920; cv=none; b=FIXIjbbNZYW3DagqgsfIH4L1B64Z0UYjpW2K+L8BRW065L/RrvPUDsvrzWCxZYoidoAh/05sQpt0W6czlQOv8rzKPqt3sc/TuhrV9oi3d8rtp+o5SOC7NplrrYzJwzUCTk6S/cnz9GZkKMnHJODCwz1qQnRftsEI9o+ACOSb3to= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742394920; c=relaxed/simple; bh=2hFThKx49oxz27PHz3w7DmRpLcx7evRFPIMWkshsjnk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VouijtTAc1NolyUJe3/HKyzHUuMtw0YveHl1uj3qwtfBm74Xd1pW0MAVLttrVCQfEPY6KYlEXa2djLRMgspIjYDAnvZo1eJMCf+2ElVK35vkqVQ6fJiDDE3J9H2LOwc9z4nvMidI7PjcdNyi/1s882c7E/JVm4tL4EyJQK/pY4c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RCsoz63+; 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="RCsoz63+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A281C4CEE4; Wed, 19 Mar 2025 14:35:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1742394920; bh=2hFThKx49oxz27PHz3w7DmRpLcx7evRFPIMWkshsjnk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RCsoz63+mdTNbzaHtRtAojbffnC1t32Tn33kvkRtEi6aNr3jDz+M6mwRssbRcbDuD AndNgzI0k/wiv8AsnHdVFja9S/7LRJhDvdnBbfphNGwtdTndXLYso0h07ILIvxsfYY W8mFYPW7KfdkyPw4623TRf9vha71pLIv82ZOef7I= 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 6.13 131/241] sctp: Fix undefined behavior in left shift operation Date: Wed, 19 Mar 2025 07:30:01 -0700 Message-ID: <20250319143030.967150625@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250319143027.685727358@linuxfoundation.org> References: <20250319143027.685727358@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 6.13-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 c241cc552e8d5..bfcff6d6a4386 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