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 1E44518BC36; Wed, 19 Mar 2025 14:40:44 +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=1742395244; cv=none; b=AgRR9dQc17W0BZqjM9wjBVP7o3RWN+zMGleP3Y2eC5K/xGWwAi3CoHLgVrC3ipImWThfIZCzgFLn+u75MFHQYg7ykrIdyD3TnQn6VFngajviwpuLiPMF4ra+GoB4YvjMQawpm091cDqoAo1GXe9rLrgyvdBYboAX3x8lxVzNWQw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742395244; c=relaxed/simple; bh=BjPGh+rQ4tY1x1f1FAC0J3dj9ra8I1dSUklBrEA+tjw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dp350eUcIEcS7q7QVEiIY+twUNVoNeVNM0Ubf0ikbIP6tKnn12mYHcdmmgb+ZqSkRTl/W5TpIvajLhPbTlYlsGSOPtHLsI4m4v7EWa3k1Y397ReJL/Ze2wOMlnz7XBSg/TgHcI86prDGHHSs2N2HZP7REnYg0ANnnivEx8ipboM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dnJcbACW; 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="dnJcbACW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7079C4CEE4; Wed, 19 Mar 2025 14:40:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1742395244; bh=BjPGh+rQ4tY1x1f1FAC0J3dj9ra8I1dSUklBrEA+tjw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dnJcbACWyaBKHV9EwSXs7DzRvfHLq33NSE79TB28/vFIJ3yXFlGTGCIa/A5XamWFz r8oamuSSYShX8ba+ydSzw7r4KiErKKIhYrKGX60CS7rk0OzX+HTklTqAofgnWK72Rr aMIEj8rIxx6j8Cxs46RJQNRJsmgUZtV+gI/9yk3Y= 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 6.6 081/166] sctp: Fix undefined behavior in left shift operation Date: Wed, 19 Mar 2025 07:30:52 -0700 Message-ID: <20250319143022.209806284@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250319143019.983527953@linuxfoundation.org> References: <20250319143019.983527953@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 6.6-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