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 479B1267F55; Tue, 8 Apr 2025 11:41:17 +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=1744112477; cv=none; b=a30goNw/9eUe/JDuOkRF5i0G7Uqx6xycTX4lt8Fl7TYG13eIUd3z7pm04ndlQqVICMGogU8dyHVnVagMVp+dYn3ROS6OOpjeV2n/fq+vtOSVQ9mkUNOGMRuZQmU/TtQLblwQufb+B4hD61RY7ZH7ltqVyJ3uQVMjV21P49F3v1c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744112477; c=relaxed/simple; bh=rnOqrvysp7JUzWgGS5VYRw6rtUKvkutfZzPmMM32SMo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XYbKBR4NomCig8sen1t37pYFB+xk+Hv8kfnDWw2do03/ZBsWaBsU7RnwLGNi4wkIDHJXNhcihpaVBGPuF87E20K+VPwLzv+goiOhhUNcJzTnWY42kGVm4l1g7eFAPIk4xXkxc2XjVfYiHtLqaI57BB1ZgsZWYcP5HlLVSxqRxbg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TtgaIGSX; 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="TtgaIGSX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF6E4C4CEEC; Tue, 8 Apr 2025 11:41:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744112477; bh=rnOqrvysp7JUzWgGS5VYRw6rtUKvkutfZzPmMM32SMo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TtgaIGSXdfq5YarCxHzks3QI2GAI0P3kHe/8eqq/lCDcS9VtpB1NSGX0Z+3oBvImC wG33+qpxe4fCIGSM38y/morBAjoaoDtl1a8lzQwHHOn0TznAVFh1MG6fTBWmc46gIa QLsImzDWd2yqaor50N96UNClCeA1TBfLNLe8xz0k= 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 5.15 043/279] sctp: Fix undefined behavior in left shift operation Date: Tue, 8 Apr 2025 12:47:06 +0200 Message-ID: <20250408104827.541701645@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104826.319283234@linuxfoundation.org> References: <20250408104826.319283234@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 5.15-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 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