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 E518E13DBB3; Tue, 27 Feb 2024 14:12:45 +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=1709043166; cv=none; b=qKecVx0BGG0Oc0s3XUNxsxMERG4clippFS8sR/sT5Mc1CLZJOD0R4nRAYLMY05mmdK0JTF2EXRr5oe58HjgnzFxenniU1nbnstykLZq82TkkbEy5XXGeGcdw27BVxQ4t1pqICKBNf2q0+J10oK2RYET7NQMHfX/0dU9iKCdmTkM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709043166; c=relaxed/simple; bh=skDAIycBV1gQzIOuNAd2fziV9pXMNJrhCCrkB/DKwvY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YIxKmisnmmRXr+mWSENiI/hY/+Rrowz2uwKDieujS6LNmfbV++0NIzX8nCNGruZXrkqliRXnY2cIbu7dbDiupG/eIrJRP5dibTLZ1W8tZ8/xVc8MnReYBNUtc5jGfcn324Oci19xTNe3EEUdlPbPe90dYMWytItJhY3X0y7H2tY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Mpus6TsF; 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="Mpus6TsF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71060C433C7; Tue, 27 Feb 2024 14:12:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1709043165; bh=skDAIycBV1gQzIOuNAd2fziV9pXMNJrhCCrkB/DKwvY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Mpus6TsF3y4/DwLncVJxXhhy2XsiZwaJQ4jpbJn2WIBGZJC9Vz55NwTPgeceeQsXo FDYJGZD8IkWUkkUxHCBMGDYcEoUVI1HPWpMv+ONFjKk8J23Rv+P8SqsAzDuqaWkDZ3 lh/tI5Se1eKEeZ8G/aFnQg7ZBrfUs7cqUHZInHNs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Cyril Hrubis , Ingo Molnar , Mahmoud Adam Subject: [PATCH 6.1 004/195] sched/rt: Disallow writing invalid values to sched_rt_period_us Date: Tue, 27 Feb 2024 14:24:25 +0100 Message-ID: <20240227131610.542549606@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240227131610.391465389@linuxfoundation.org> References: <20240227131610.391465389@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cyril Hrubis commit 079be8fc630943d9fc70a97807feb73d169ee3fc upstream. 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 Cc: Mahmoud Adam Signed-off-by: Greg Kroah-Hartman --- kernel/sched/rt.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -37,6 +37,8 @@ static struct ctl_table sched_rt_sysctls .maxlen = sizeof(unsigned int), .mode = 0644, .proc_handler = sched_rt_handler, + .extra1 = SYSCTL_ONE, + .extra2 = SYSCTL_INT_MAX, }, { .procname = "sched_rt_runtime_us", @@ -44,6 +46,8 @@ static struct ctl_table sched_rt_sysctls .maxlen = sizeof(int), .mode = 0644, .proc_handler = sched_rt_handler, + .extra1 = SYSCTL_NEG_ONE, + .extra2 = SYSCTL_INT_MAX, }, { .procname = "sched_rr_timeslice_ms", @@ -2970,9 +2974,6 @@ static int sched_rt_global_constraints(v #ifdef CONFIG_SYSCTL 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) || ((u64)sysctl_sched_rt_runtime * @@ -3003,7 +3004,7 @@ static int sched_rt_handler(struct ctl_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();