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 162532590 for ; Sun, 22 Jan 2023 15:22:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F931C4339B; Sun, 22 Jan 2023 15:22:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1674400962; bh=/Uno6CNghRPuHpGDj4yWJHMULz9EGKGJEn1hF6JWJwQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DJfT6CEEyt7jSEyJOMxCO/tecgwwjJ6m27vnyzRvnt2SlCjxq+UeFWq0N1bVLI9qR U0QMaAi67DOcA9a81UnJsVqv8YgFHwQCuKAoxnRNyB6/UmyFF+gRJB8/VTuw2CaAIZ At5WxTBO2Ln6xaw0v2fokVixO5Cf7C9v3Z/+v/ow= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jordy Zomer , Linus Torvalds Subject: [PATCH 6.1 057/193] prlimit: do_prlimit needs to have a speculation check Date: Sun, 22 Jan 2023 16:03:06 +0100 Message-Id: <20230122150248.943178253@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230122150246.321043584@linuxfoundation.org> References: <20230122150246.321043584@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman commit 739790605705ddcf18f21782b9c99ad7d53a8c11 upstream. do_prlimit() adds the user-controlled resource value to a pointer that will subsequently be dereferenced. In order to help prevent this codepath from being used as a spectre "gadget" a barrier needs to be added after checking the range. Reported-by: Jordy Zomer Tested-by: Jordy Zomer Suggested-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- kernel/sys.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1442,6 +1442,8 @@ static int do_prlimit(struct task_struct if (resource >= RLIM_NLIMITS) return -EINVAL; + resource = array_index_nospec(resource, RLIM_NLIMITS); + if (new_rlim) { if (new_rlim->rlim_cur > new_rlim->rlim_max) return -EINVAL;