Commit-ID: f45c2a079f129fa296335f2c5363852daf71f723 Gitweb: https://git.kernel.org/tip/f45c2a079f129fa296335f2c5363852daf71f723 Author: Reinette Chatre <reinette.cha...@intel.com> AuthorDate: Tue, 29 May 2018 05:57:45 -0700 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Wed, 20 Jun 2018 00:56:34 +0200
x86/intel_rdt: Protect against resource group changes during locking We intend to modify file permissions to make the "tasks", "cpus", and "cpus_list" not accessible to the user when cache pseudo-locking in progress. Even so, it is still possible for the user to force the file permissions (using chmod) to make them writeable. Similarly, directory permissions will be modified to prevent future monitor group creation but the user can override these restrictions also. Add additional checks to the files we intend to restrict to ensure that no modifications from user space are attempted while setting up a pseudo-locking or after a pseudo-locked region is set up. Signed-off-by: Reinette Chatre <reinette.cha...@intel.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: fenghua...@intel.com Cc: tony.l...@intel.com Cc: vikas.shiva...@linux.intel.com Cc: gavin.hind...@intel.com Cc: jithu.jos...@intel.com Cc: dave.han...@intel.com Cc: h...@zytor.com Link: https://lkml.kernel.org/r/14b7a6e8ab2991130a98381d7075bb254e761050.1527593971.git.reinette.cha...@intel.com --- arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c | 10 +++++++++ arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 32 +++++++++++++++++++++++++---- 2 files changed, 38 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c index 0e6210a043f0..bc79396c5dad 100644 --- a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c +++ b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c @@ -283,6 +283,16 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of, } rdt_last_cmd_clear(); + /* + * No changes to pseudo-locked region allowed. It has to be removed + * and re-created instead. + */ + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) { + ret = -EINVAL; + rdt_last_cmd_puts("resource group is pseudo-locked\n"); + goto out; + } + for_each_alloc_enabled_rdt_resource(r) { list_for_each_entry(dom, &r->domains, list) dom->have_new_ctrl = false; diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index 33088625257e..e27583f3823e 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -449,6 +449,13 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of, goto unlock; } + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED || + rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) { + ret = -EINVAL; + rdt_last_cmd_puts("pseudo-locking in progress\n"); + goto unlock; + } + if (is_cpu_list(of)) ret = cpulist_parse(buf, newmask); else @@ -651,13 +658,22 @@ static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of, if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0) return -EINVAL; rdtgrp = rdtgroup_kn_lock_live(of->kn); + if (!rdtgrp) { + rdtgroup_kn_unlock(of->kn); + return -ENOENT; + } rdt_last_cmd_clear(); - if (rdtgrp) - ret = rdtgroup_move_task(pid, rdtgrp, of); - else - ret = -ENOENT; + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED || + rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) { + ret = -EINVAL; + rdt_last_cmd_puts("pseudo-locking in progress\n"); + goto unlock; + } + + ret = rdtgroup_move_task(pid, rdtgrp, of); +unlock: rdtgroup_kn_unlock(of->kn); return ret ?: nbytes; @@ -2307,6 +2323,14 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn, goto out_unlock; } + if (rtype == RDTMON_GROUP && + (prdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP || + prdtgrp->mode == RDT_MODE_PSEUDO_LOCKED)) { + ret = -EINVAL; + rdt_last_cmd_puts("pseudo-locking in progress\n"); + goto out_unlock; + } + /* allocate the rdtgroup. */ rdtgrp = kzalloc(sizeof(*rdtgrp), GFP_KERNEL); if (!rdtgrp) {
