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 273A113A25D; Tue, 27 Feb 2024 13:44:15 +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=1709041455; cv=none; b=OlTlCO3wt+xhUobU98P/6rqIyPkB+lRXs740U7OxgDbeXBR+VxptmC2f9xlRvgw1ByxfZFebG8pBYoeFljTjh+yPJAJnrNsj0oqiUu7U6E3H2oVwg6WYrY1jFwqKiHNfMfbc6gG2KcKVMprPzDdsqkdsRtkyHTcLRWiH3AyCGGE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709041455; c=relaxed/simple; bh=OOrHrfRxqmMlCzcTN7kRrxUYyDdGYgK9kZmkiAH1cOM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nfE21zgz2jqVlQkSKWLVEnUS621iGSao/0E6dEgOj/cEoFIQUXC4lio8q4Jm5LeN6yXLwOf2eONO1jmy/AYizJ8ETsF05ikybviF0+pxKs4qJAzY0dVF82GBhe0a5I1IKatv10yH9VQVJC0RGbr43v5vWwO/wlxl3EoRg5EL9TM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CtOM72AU; 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="CtOM72AU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F9D5C433F1; Tue, 27 Feb 2024 13:44:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1709041455; bh=OOrHrfRxqmMlCzcTN7kRrxUYyDdGYgK9kZmkiAH1cOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CtOM72AU/i9INvo+OWWDhRpnjuX3lQbnTXQBZQ3YKrlvrcSW/SMTwPkBX4+ggNyaw YaudurBlJyysvhJiT72GAmwzCMdfKbLdVmTO5eqkrdN0y0ughlWwk9BasTyif0yHAR kLVsZu1DuSg529/bjdMniDBxWG3ZWXLXYbv174Ew= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Cyril Hrubis , Ingo Molnar , Petr Vorel Subject: [PATCH 4.19 11/52] sched/rt: Disallow writing invalid values to sched_rt_period_us Date: Tue, 27 Feb 2024 14:25:58 +0100 Message-ID: <20240227131548.904890318@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240227131548.514622258@linuxfoundation.org> References: <20240227131548.514622258@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cyril Hrubis [ Upstream commit 079be8fc630943d9fc70a97807feb73d169ee3fc ] The validation of the value written to sched_rt_period_us was broken because: - the sysclt_sched_rt_period is declared as unsigned int - parsed by proc_do_intvec() - the range is asserted after the value parsed by proc_do_intvec() Because of this negative values written to the file were written into a unsigned integer that were later on interpreted as large positive integers which did passed the check: if (sysclt_sched_rt_period <= 0) return EINVAL; This commit fixes the parsing by setting explicit range for both perid_us and runtime_us into the sched_rt_sysctls table and processes the values with proc_dointvec_minmax() instead. Alternatively if we wanted to use full range of unsigned int for the period value we would have to split the proc_handler and use proc_douintvec() for it however even the Documentation/scheduller/sched-rt-group.rst describes the range as 1 to INT_MAX. As far as I can tell the only problem this causes is that the sysctl file allows writing negative values which when read back may confuse userspace. There is also a LTP test being submitted for these sysctl files at: http://patchwork.ozlabs.org/project/ltp/patch/20230901144433.2526-1-chrubis@suse.cz/ Signed-off-by: Cyril Hrubis Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20231002115553.3007-2-chrubis@suse.cz [ pvorel: rebased for 4.19 ] Reviewed-by: Petr Vorel Signed-off-by: Petr Vorel Signed-off-by: Greg Kroah-Hartman --- kernel/sched/rt.c | 5 +---- kernel/sysctl.c | 5 +++++ 2 files changed, 6 insertions(+), 4 deletions(-) --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -2658,9 +2658,6 @@ static int sched_rt_global_constraints(v static int sched_rt_global_validate(void) { - if (sysctl_sched_rt_period <= 0) - return -EINVAL; - if ((sysctl_sched_rt_runtime != RUNTIME_INF) && (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) return -EINVAL; @@ -2690,7 +2687,7 @@ int sched_rt_handler(struct ctl_table *t old_period = sysctl_sched_rt_period; old_runtime = sysctl_sched_rt_runtime; - ret = proc_dointvec(table, write, buffer, lenp, ppos); + ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); if (!ret && write) { ret = sched_rt_global_validate(); --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -127,6 +127,7 @@ static int zero; static int __maybe_unused one = 1; static int __maybe_unused two = 2; static int __maybe_unused four = 4; +static int int_max = INT_MAX; static unsigned long zero_ul; static unsigned long one_ul = 1; static unsigned long long_max = LONG_MAX; @@ -464,6 +465,8 @@ static struct ctl_table kern_table[] = { .maxlen = sizeof(unsigned int), .mode = 0644, .proc_handler = sched_rt_handler, + .extra1 = &one, + .extra2 = &int_max, }, { .procname = "sched_rt_runtime_us", @@ -471,6 +474,8 @@ static struct ctl_table kern_table[] = { .maxlen = sizeof(int), .mode = 0644, .proc_handler = sched_rt_handler, + .extra1 = &neg_one, + .extra2 = &int_max, }, { .procname = "sched_rr_timeslice_ms",